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Hypergrid 1.5: Building the Metaverse, one grid at a time
by Gwyneth Llewelyn|Published August 24, 2010 |7 Comments
Linden Lab has announced at the SLCC their continuing support of the open source efforts: the launch of Snowstorm, the project for a new viewer (based on the Snowglobe 2.X codebase) which will get Lindens and third-party volunteer developers working much, much closer together to develop what Philip Linden hopes to be the ultimate viewer, or, as he says these days, "to bring Linden Lab back to the lead in innovation and technology". Tateru Nino has already commented a bit on the change of strategy; I have to humbly confess that I'm not familiar enough with the Scrum methodology to comment if it's the best way to deal with a fast pace of development that includes a lot of external developers. Still, some things look interesting: for instance, in theory at least, the Emerald team could branch off one fork of the Snowstorm code to implement their spell-checking functions, manage it as if it were their own personal in-house project, release a build for open testing by any resident, and after a few weeks, commit it back to the main code — and this would become an "official" Snowstorm release (which will happen every other week). Sounds reasonable? Well, yes; it's also a way to get more people to help out Linden Lab to fix bugs, now that they have fired so many developers (but they still have 175 working at LL on 15 different teams, says Philip).
On the other hand, the other major open source project at Linden Lab, intergrid connectivity, seems to have been dropped, possibly indefinitely. This is indeed bad news. Around this time, the IETF should have been able to come up with some relatively final standards for the intergrid protocol VWRAP. But if Linden Lab drops their commitment to it, the future is not very bright. On the other side of the coin, we have the OpenSimulator community with its amazing Hypergrid protocol, currently at its 1.5 incarnation, and which is simply mindboggling in the way it operates.
I had to try it out for myself 🙂
An image is better than a thousand words, a video is better than a million…
The best way, I guess, is to show a video, and this is what I've done. Please understand that pretty much everything you will see runs on low-to-average hardware and connectivity. After you watch it, some explanations are due…
On the above video, I mostly wanted to make three points. First, and perhaps the most important point, it works. And it works way better than I imagined. Secondly, that OpenSim, in spite of its insanely fast pace of development, is still very flaky — some might compare it to what Second Life did in 2002 or early 2003: most things work some of the time, but failure is usually catastrophical. And thirdly, we're slowly getting all the pieces assembled together: with every new iteration of OpenSim, it comes closer to become what people have in mind when thinking of a true Metaverse — lots of virtual worlds, each running independently of each other, but all joined together in a chaotic weave of interconnections between each other. While some of the steps shown on the video might not be very impressive yet, the underlying technology is everything we have been hoping that Linden Lab developed and that we asked from them as early as 2006 or so. It's more than merely a "proof of concept" or a "nice prototype": now we can actually use it, even though patience is required — the technology is at the alpha stage, and will remain so for many, many years.
You'll see that I often stop to type strange links in chat, and then click on them. This is how Hypergrid teleporting is implemented, and it's viewer-independent; it also works on the SL viewers. For instance, while a link to a sim on LL's SL Grid is simply secondlife://Beta Technologies/128/128/40 (if you copy this and paste it on your viewer, you can click on the link, and teleport there), for links on OpenSim grids, you just add the grid URI: e.g.
secondlife://opensim.betatechnologies:8002/Beta Technologies/128/128/40
should allow you to teleport from any OpenSim grid with Hypergrid 1.5 to my company's sim on our own grid. The secondlife: tag just describes the protocol, not the grid. So, yes, there are ways to distinguish grids pretty easily: the login URI is unique for every grid.
Some background on the underlying technology
Let's scroll back to the beginning. Linden Lab's Second Life Grid® is a technology based on a set of fixed assumptions. There is a large array of central servers (which nobody outside the 'Lab knows what they are or how they're configured). Then there is a vast number of some 5,000+ servers, all using relatively similar configurations (servers of the same class have similar hardware specs, and they all run the same software), which, in turn, run the simulator software (sims), each region running on its own virtual machine (4-16 can run on a single server, although semi-official rumours claim that LL has been experimenting with higher density of CPUs, and may have one day 64 openspace regions on a single server). All this is automated: from the installation of the operating system to the region simulator, it's all done with point-and-click configuration to set them up when someone buys a region from the Land Store.
Things started to become confusing when Linden Lab started to move out of a single co-location facility. Now all of a sudden, some sims would be running outside the network where the central servers were. Apparently, the addresses of those servers are hard-coded in some way, so the solution was to create first a VPN between co-location facilities (which are a software-based solution to make external servers "look like" they are in the same physical network), and, later, to simply run fibre between the co-location facilities, effectively placing the servers once more in the same physical network.
Some comments made by the engineers (like this explanation by FJ Linden, which followed a more thorough description of how the grid is physically implemented) explained that some co-location facilities actually ran some of the central asset servers: Dallas and Phoenix apparently have their own central servers, while Washington DC has not. It's not clear if they're just clones of each other and kept in sync (like during an earlier implementation). Also, thanks to HTTP downloads of assets, implemented last week, now the core of all requests to the asset servers can be pushed into the Amazon S3 cloud, saving precious bandwidth, and providing Linden Lab an increased layer of reliability — Amazon S3 is way more stable than LL's own setup, merely because that's the core service they provide, and cloud technology is currently the best known way to provide almost infinite redundancy.
Nevertheless, what is important in this picture is that all of the Second Life Grid runs on an unified system. There is just a single architecture for the whole grid. Of course, individually, there are thousands of servers to track down, but all work pretty much the same way.
Now contrast that with the rest of the Internet! Each system, each network, each computer, each node is different. Servers and active network devices have all sorts of possible configurations. From smartphones to high-end routers, from home-run Web servers on old hardware to complex cluster solutions and massively parallel supercomputers, to cloud computing — each system is uniquely managed, and each architecture is different. Google might have more servers than Amazon or Microsoft, and although their specs are the same on all of Google's co-location facilities around the world, their configuration has nothing to do with what their competitors have — and vice-versa. There is no "standard" way of connecting servers and networks to the Internet-at-large, except for one thing: they all speak the same protocols.
The difficulty that Linden Lab had when they started moving servers to a different co-location facility was that their architecture was never planned to be anything but uniform. Merely having "two locations" introduced a new layer of complexity that was never foreseen. Sims, although pretty much independent from each other, were designed to work in the same network and connect to the same central servers. Everything was designed from the ground up having one grid in mind.
The heterogeneous OpenSim
Enter OpenSim deployment. Just like the Internet, there is no one-size-fits-all technical solution to implement them. It runs (at least) on Windows, Mac, and Unix back-ends — in fact, on anything that runs Mono. And several different Mono versions are possible (although early ones might simply not compile OpenSim). Servers can be co-located at high-end data centres with unlimited bandwidth, or behind corporate/academic firewalls, or just underpowered PCs in a basement connected to a home ADSL solution — or run from your laptop. OpenSim can be configured as a standalone version, or have separate central servers. The whole range of configurations include standalone sims connected to external central servers, all central servers on a single machine or on separate ones (that includes moving the database servers out for increased performance and reliability), or Hypergrid-connecting several servers which are technically under the same grid, but actually have separate storage on different places. Servers hosting sims are not limited to a single location: they can be spread around the campus, or even around the world, according to needs or capabilities. For instance, a multi-campus, multi-department university or corporation might have sets of servers running at each department, but keep the central servers for all the organisation on the main data centre. Or each department might have their own central servers. Or students (or employees) might just add their own regions running from their own desktops and connect "on demand" at will. Finally, unlike some have claimed in the past, all this can be made secure, using passwords and encryption to make sure that only allowed regions are actually interconnected with each other.
But it's not just about running OpenSim in the same organisation. Thanks to Hypergrid, you can interlink different grids from completely different organisations. You set the level of trust you wish: you can set aside some public regions on your grid and allow everybody to teleport to them; or you can conditionally allow just incoming teleports from grids you trust; or simply shut the whole world out of your grid. Hypergrid links are actually just URLs, and, like on the Web, if you know the link, and it allows incoming users from other grids, you can then teleport to them. The analogy to the Web is really almost flawlessly implemented.
It has a twist, though, one that was not implemented on the Web as Tim Berners-Lee designed it. Avatars are not simply "dumb viewers". They carry identity with them: a name, their origin (the grid they come from), and, of course, the avatar's precious inventory. The equivalent on the Web would be the ubiquity of identity providers (Facebook logins, for example) where your profile data is "carried" with you when you log in to a third-party site with a Facebook login. The difference is that on the Web there are no standards (OpenID and Oauth are two attempts to standardise the process, but the Web is not consensual about a single protocol to deal with identity — you just have to deal with a multiplicity of different identity providers, and support as many as you wish). Also, "identity" on the Web is rather limited in what is stored: mostly just the name, email address, and sometimes the profile picture is carried from one website to the other.
On the metaverse, the avatar and its inventory — plus the 2D profile info — are part of the identity as well. And Hypergrid 1.5 neatly addresses it quite well. You really have to experience it to get fascinated. All your inventory comes with you when you log in to another grid, but your items are not immediately available to the other grid even though you see them in your inventory — you need them to be rezzed first. When you do that, the item is tagged with your creator tag (even across grids!) and with a set of permissions you assign to it. Similarly, if you buy content on a foreign grid, and teleport back home, it gets stored in a special new system folder called "My Suitcase". These flag content from external grids, which are available on the foreign grid central servers, and which only move to your region if you rezz them.
Two other layers of absolute coolness have been designed into the system. One, of course, is what content is allowed to be transferred. You can configure OpenSim to not allow any content to move out of your grid. Similarly, you can prevent content from other grids to be brought into yours. While critics might say that this doesn't cover all possible options, it goes a long way to implement minimal protection. Obviously that a grid owner can see a rezzed object and copy it directly from the database, and you can't prevent that from happening — but that's exactly the same argument as being impossible to prevent your avatar and attachments and rezzed objects to be copybotted on the Second Life Grid. There is simply no way to prevent that from happening.
But at least you have some control. If you do not rezz an object in a foreign grid, nobody can get that object forcefully out of your inventory — exactly like on the Second Life Grid. A visible object, of course (just like in SL), can always be copied illegally.
Giving OpenSim users the same kind of content protection that they get in Second Life (not more, not less) has made some content creators be bold enough to start selling that content on some OpenSim grids. And when I say "selling" I really mean a working economy with the possibility to exchange virtual money with so-called real money. And working across grids, too. All this is not only possible, but it has been fully implemented by the Austrian company VirWoX, who run a money exchange for several grids and for Second Life as well. This actually means that yes, you can transfer L$ to a few OpenSim grids… or use any of the many payment services (including bank transfers!) to put some money there. The important thing is that even though your "favourite" grid is not among the ones listed, you can still get "Open Metaverse Currency" dollars, and just teleport to a grid which accepts them, shop there, and go back to your "home grid". The underlying technology has been co-developed with the University of Graz, and dozens of more grids are currently beta-testing the concept, so I imagine that the list will grow — as will the number of "competing" exchanges, of course.
Something you won't see on the video is testing voice or cross-grid profiles. Voice is quite interesting. As some of you might now, Linden Lab uses Vivox as their voice provider, probably because Vivox has a lot of experience with providing VoIP for games and virtual worlds. Well, you can buy a license to use Vivox with OpenSim too. But you have far more options. OpenSim supports open source VoIP providers as well, Freeswitch being currently the more popular choice, but it's not the only one. The interesting aspect of voice is that you can interconnect VoIP switches with each other and with the phone network. So, yes, this means that in theory you can talk on the phone with someone in OpenSim, much like the (now closed) AvaLine service once provided by Linden Lab. Depending on the technology used, spatial sound (like in SL) might even be supported as well.
Then there is cross-grid messaging, cross-grid profiles, and a lot of other services that can optionally be provided across interconnected grids. They require special plugins and a backend server to deal with them (popular options include SimianGrid, which is a separate project, but well integrated into OpenSim. The beauty of the technology is that it's all Web-based with neat APIs. This means that all can call functions from remote servers pretty easily.
So… to recap, this is all that works in OpenSim these days: intergrid teleportation with cross-grid content transfer, with permissions and creation tags; groups; inter-grid profiles and communication; voice with telephony integration. Not too bad! And it still manages to do all of that fully compatible with the latest official SL viewers. If you use a tweaked viewer like the ones from realXtend, you can even get meshes; and some minor things, like saving WindLight settings on each sim, or having prims over 10 m, also work nicely. As does sim backup and inventory backup… and so forth.
Not everything is bright and shiny, though. The major difference these days is the comparatively low stability of OpenSim. It's far too easy to crash sims. Dealing with a lot of avatars in the same place is also not so easy as in SL: performance degrades very quickly. Overall, it looks and feels like SL in 2003, even though OpenSim replicates pretty much everything that SL supports today (active work is being done on supporting HTML-on-a-prim as well), except perhaps for the more complex land and group operations, and adds a lot of extra features.
Then there is the whole issue of configuration. Although you can install the Diva Distro or the OSGrid distro (which will preconfigure your sim to immediately join OSGrid, one of the uncountable independent grids out there, and one of the oldest and most popular) on Linux, Windows and Mac users have no equivalent solution. It means a lot of time to learn how to properly do it, and documentation is sparse and mostly incomplete: OpenSim's eternal "alpha" stage of development means that getting help for it is hard, and usually done via IRC or the official mailing lists, and on some independent forums. Some grid operators also offer a degree of technical support. But it's still hard, compared to using any other Internet application server.
And that's just for a standalone server. Creating your own grid, specially if it's for more than just a quick test, is overwhelmingly complicated: you not only require good system administration skills, but also a thorough understanding of the actual codebase, and the way all components interact. These days, 13-old kids can easily turn their home PCs into a full-fledged Web server (or games server!) by just installing a few packages according to a "recipe" — and the defaults will be good enough to get reasonable performance. It's just when you need to deal with dozens of thousands of daily hits on your webserver that you need to worry about tweaking the system.
With OpenSim, except for quick tests on standalone servers, it means dealing with the architecture from the very first day — unless you couldn't care less about installing OpenSim but just about using it.
But even becoming merely a "user" is not as easy as in Second Life. There are literally thousands of grid operators. Although all could theoretically be integrated with each other, in practice not all have Hypergrid 1.5 enabled. A few grids still support Hypergrid 1.0, which has far less features and has little IP protection (it was a great way to test the concept, though!). Ironically, the larger the grid, and the more popular it is, the less likely their operators will turn on Hypergrid, or even have the sims updated to the latest versions. While I might just be mean, I think they do it on purpose — very likely for the same reason that LL has abandoned interoperability: they want to capture their own share of users, not let them roam freely across grids, since their revenues come, like LL, from tier costs and eventually from their internal economy server, and the more registered avatars they have on their grid, the better.
This means that some events happening on one popular OpenSim grid might be available only to the users registered on that grid, and be closed to the others. Of course most grids are open and allow easy creation of avatars — but then it means starting all over again.
Imagine a Web where in theory everybody was using HTTP for the protocol and HTML for rendering the web pages… but in some cases you could only reach the page if you were a specially registered user on that website. That's pretty much what all those OpenSim grids have: all are potentially reachable via Hypergrid, but only some actually allow it. It feels strange… until you remember that Facebook, LinkedIn, Plaxo, etc. work similarly: only registered users that are friends of each other get full access to each other's pages. Visitors, finding one of those pages througha a Google or Bing search, will just get limited access (or no access at all).
Once you've logged in, and even teleported across a few grids, there comes another obvious problem: search. OpenSim allows all sorts of hooks to enable content to be exposed to external search engines (similar to what LL does on the SL Grid, where you can, indeed, search for residents' profiles on Google, if they're checked to allow publishing on the Web). But this doesn't work that well — yet. There is no "universal" intergrid search: at best, you can search for groups (works well with an external module) and residents on the grid you have registered with. Map search works very well inside the grid you're currently on. However, you can't search for, say, a specific sim which you remember to have visited once but have no clue on which grid it was.
Content search doesn't work at all, at least definitely not on the standard OpenSim installation — many grid operators offer either an in-world search or, just like XStreetSL/SL Marketplace, they simply have their own web-based marketplaces. I haven't tested if they can actually deliver content across grids; my guess is that you have to be logged in on the grid where the content is hosted, or the delivery will fail (but your money will be gone!). No, there isn't yet an "intergrid marketplace", although I can imagine that soon someone will attempt to do that. It shouldn't be too hard: once you've designed your marketplace for a grid, and thoroughly tested it to see if it works well, it should be able to deliver content on any grid where you can place one of those merchant boxes. Each grid is usually identified with different tags from the perspective of the programming, and it's easy to figure out which sim on which grid hosts the merchant box.
Some things which we take for granted actually work differently, and in unexpected ways. For instance, if you IM someone from your grid who is offworld, and your grid operator has enabled IM-to-email, you might get the IM on your email (sometimes it doesn't work… don't ask me why). But if you are online on your grid, and your friend is on a different one, this won't trigger IM-to-email. Giving items is also a bit tricky. You cannot give someone else an item unless you are both logged in on the same grid, no matter what your original grid is. And I don't think that befriending people works across grids, although, granted, I haven't tried that often enough. So there is not yet an intergrid presence system. Since, however, most of the underlying communication layers have been moved to Web-based calls, I imagine that cross-grid presence might get theoretically implemented in a future release of Hypergrid.
As a side-note, one of the projects that Philip announced as part of their priorities is fixing their whole presence mechanism. Although this might sound absurd to many, there is really just one communication protocol: IM, which is asynchronous and uses UDP messaging. Sending L$ is a specially-formatted IM (that's why you never know if the money reaches the destination, it's not an atomic transaction!); so are content transfers, and, of course, group chat. When someone comes online, an IM is sent to every friend who has you on the list saying "X is online" (that's why it's always a good idea to turn that setting off — it will dramatically improve your SL experience!). Everything are IMs! Until recently, even IMs sent across sims would be implemented, well… you guessed: with IMs between servers. 🙁 (Note: I understand that this might have changed recently)
OpenSim is a bit more clever. While the client requires IMs, group chat, money, and content transfers to be received as IMs (and sends them as IMs to the grid), the server is up to the OpenSim developers. What they do is to have the sim funnel all those messages to a "Messaging Service", and distribute it from there. At the sim level, you can configure some special hooks to allow messages to go elsewhere; one of the first popular modules for OpenSim was to hook it up with an IRC server, where sims and groups become channels and personal IMs just become private IRC messages. The beauty of that is that IRC, although old, is a very familiar protocol which has long passed the test of time and is known to be able to handle nicely millions of users in a distributed way.
Nothing requires using a SL-compatible "Messaging Server", though. You can totally replace it by something else — say a Jabber/XMPP server, and redistribute presence, messages, money, and content via a XMPP federation. Hook it up with GTalk, and with a plugin, you could in theory send content and L$ from GTalk to an OpenSim grid and vice-versa 🙂 This separation of layers exists in OpenSim since, oh, 2007, I guess; LL is just starting to do the same thing for their own grid…
So I can imagine that it should be easy to replace the current Messaging Server by something that works across grids. After all, they already did that for profiles, too.
Nevertheless, the same caveat applies: while in the future some grid operators might allow their own Messaging Servers to talk to others, some may not. You can see a pattern here… although OpenSim allows a lot of nice extra features, and all recent versions implement them neatly (or at least provide hooks to allow them), that doesn't mean that the grid operators actually enable them. As more and more people register for an OpenSim grid, possibly lured by the ease of jumping across grids, and start adding friends here and there, and buying content on some grids and bring them to others, they might soon find out that each grid works slightly differently than others. My typical example is the Animation Overrider: only in OpenSim 0.7.X I got one version consistently working fine (I understand some people have simpler variants which have been working for a long time). In theory, I should be able to use my AO on any grid I can teleport to using Hypergrid 1.5, because only OpenSim 0.7 supports that; however, many grids haven't yet upgraded to 0.7, or have their specially-tailored version of OpenSim, and the AO might not work on those. In Second Life, a scripted device bought anywhere will work on any sim. On OpenSim, you never know if things will work or not on other grids…
In a sense, what we will need in the future is some sort of "OpenSim Consortium" — an organisation of grid operators — that establish some guidelines on the minimum set of features to be offered to all OpenSim users, so that people don't get any nasty surprises about what they should expect to work. To be honest, that won't happen soon. Many have hoped that this "consortium" would actually be led by Linden Lab, IBM, Intel, and the remaining charter members of VWRAP — which is, for all purposes, based on LL's own ideas on how intergrid teleporting should work, with a lot of encryption code to establish authentication and authorisation tokens contributed by IBM. The problem is, as said, that LL dropped that effort. VWRAP is also insanely complex to implement compared to Hypergrid, although, to be honest, all OpenSim installations are actually able to use the very first implementation of the protocol, then named "Open Grid Protocol", which did allow teleports from LL's Preview Grid to any OpenSim grid (without any content transfer — not even your avatar would show up! — and you couldn't add items to your inventory). OGP was really just a proof of concept; LL doesn't even support it any longer, even for testing purposes, although Snowglobe still has all the code for it.
Also, it's important to understand that each grid operator has their own terms of services, and in most cases, they bear little resemblance to LL's own. Content acquired on one grid that has a strong commitment to protecting intellectual property can be theoretically bought and brought to grids that have no such commitment, and if something fails (like the permission system breaking), there is no guarantee that the grid operator will do anything about it — or even care. There is no universal Abuse Report system, and not all grid operators implement their own systems. Being rude to someone on one grid and getting banned does not mean that the same avatar cannot jump to other grids — or create an account elsewhere and use Hypergrid teleporting to come back to the original grid where they had been originally banned. Even more importantly, not all grids have the same paranoid US fear of contaminating young people's minds with the power of virtual worlds; ReactionGrid, for instance, allows K-12 kids to freely mingle with adults on the same grid, without any restrictions (except the ones imposed by the sim owners themselves). Puritans will be quite frustrated to know that non-US grids can allow legitimate casino operators to establish in-world gambling legally, and there is nobody that can prevent that (of course, illegitimate casino operators will be punishable by local laws, but it's highly unlikely that the grid operators won't be affected by that — they will just need to take down the illegitimate casino operators to comply with a court order, and go on with their business as usual). Put it simply, for the better or the worse, Linden Lab's Terms of Service do not apply to any other grid except LL's own. For some this might be a paradise; for others, a nightmare come true…
Every time Linden Lab makes another drastic announcement which will outrage a chunk of the resident community, we get a new round of self-styled prophets that announce LL's (and SL's) upcoming end. This gets so frequent that Philip even mentioned it on his SLCC keynote speech! The truth is, LL is not going anywhere, and SL is probably going to outlast all those doomsday prophets, and we have nothing to worry about.
Nevertheless, it's true that changing conditions might push more and more users out of Second Life — not because it "fails" or "ends", but because their tolerance of LL's constant blunders and fiascos has faded, and they are ready to move elsewhere. Universities and even businesses, although for different reasons (e.g. costs) might not see any point in remaining in SL any longer. However, all of them enjoy the "Second Life experience" and are not necessarily interested in going to a completely different virtual world (or go play Facebook games instead). Content creators, for example, might have accumulated over the years a lot of content and patiently acquired a skill set which took them a lot of time to develop, and they're reluctant to drop everything and start from scratch on an unfamiliar virtual world where everything is different and nothing can be re-used (not even their reputation!).
OpenSim is the choice for all of those people who love Second Life but hate Linden Lab. Of course it requires some patience with OpenSim, too. Although OpenSim sports many features that Second Life doesn't have, some of them — like grid interconnection — Linden Lab has completely wiped out of the picture, it's a far less stable and complete product, subject to many caveats. Even though setting up a sim from a pre-configured distribution might make the setup effort simple enough, actually maintaining an OpenSim grid that supports the same level of social interaction as LL's own Second Life is extremely hard (if not even impossible!), and requires high-end servers on tier 1 co-location facilities — not old PCs on someone's home — and expert system administrators with a lot of expertise in OpenSim development to keep everything working smoothly. That combination of skill and hardware is not so easy to find at most grid operators and only a limited number of grids can actually boast of providing a service which is good enough for more than casual use.
Ultimately, the choice for 2010 is still leaning mostly towards SL as the better choice — no matter how much we blame SL for the constant crashing and inventory loss and utter lack of customer support, it's far, far superior than the best of all OpenSim grids (which is still an alpha product, even though it's impressive). People selling their land in SL and leaving in fury for OpenSim full of expectations that they'll get pretty much the same experience will be immensely disappointed. Not to mention that only a tiny fraction of the content is available on OpenSim… even though it grows, and it gets better all the time, most of the best experienced content creators are still on SL and afraid to open shop on OpenSim.
But on the other side of the coin, if you just wish to join a virtual world which works most of the time, have patience to endure glitches and low performance, can be far cheaper in land, and doesn't subject you to LL's whims and ToS, OpenSim is the perfect choice for you.
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Brazil: According to UN and IACHR one environmentalist or land rights activist killed every week for 15 years
Protest in Brasilia against the killing of indigenous people
In its Annual Report for 2016, Front Line Defenders reported the killings of 281 human rights defenders in 25 countries. Fifty-nine of those killings took place in one country – Brazil. Of those killed in 2016, 49% were working to defend land, environmental or indigenous rights.
This is consistent with a pattern of killing in Brazil over decades.
A recent joint statement by the offices of the UN High Commissioner for Human Rights and the Inter American Commission for Human Rights (IACHR) said that, "Over the last 15 years, Brazil has seen the highest number of killings of environmental and land defenders of any country, up to an average of about one every week. Indigenous peoples are especially at risk." According to a 2015 report by the Brazilian NGO Conselho Indigenista Missionario (Indigenous Missionary Council or Cimi), 390 Guarani-Kaiowá leaders were killed between 2003 and 2014.
That statement is shocking enough, but when you do the math this means a figure of 780 environmental and land rights activists have been killed in that period. The vast majority of these cases are never properly investigated and it is rare for any perpetrator to be brought to justice.
This figure is backed up by research by the Commissâo Pastoral da Terra ( the Pastoral Land Commission, CPT), which shows that "since 1985, 1,833 peasants and leaders of the struggle for agrarian reform have been assassinated in conflicts over land, while during the same period of time large land estates have grown by 375%".
This is the background against which HRDs, defending the rights of their communities, are routinely killed with total impunity. While the numbers are shocking and grab our attention, what is of equal concern is the response of the Brazilian government. Rather than taking action to protect the rights of indigenous and peasant communities the government is instead actively trying to limit the legal protections they currently enjoy.
According to the UN and IACHR "Against this backdrop, Brazil should be strengthening institutional and legal protection for indigenous peoples, as well as people of African heritage and other communities who depend on their ancestral territory for their material and cultural existence. It is highly troubling that instead, Brazil is considering weakening those protections".
As noted in the joint statement, "A number of draft laws establishing general environmental licensing that would weaken environmental protection were being circulated in Congress on Friday 2 June. For example, the proposed legislation would remove the need for environmental licenses for projects involving agri-business and cattle ranching, regardless of their size, location, necessity, or impact on indigenous lands or the environment".
A recent inquiry by a group of congressmen who are supporters of the agribusiness called for the abolition of FUNAI, the National Indian Foundation, which is the Brazilian government body that establishes and carries out policies relating to indigenous peoples.
If killings on this scale took place in one incident it would be called a massacre. But because the victims are poor campesino or indigenous people living in remote rural areas there is tacit acceptance of this climate of violence which is further exacerbated by the violent response of the state itself.
The Brazilian government should be held to account for its failure to take any meaningful action to end this culture of killing or to protect human rights defenders.
Chile: "The bullet that killed Luis Marileo was fired a long time ago"
Comunidad Cacique José Guiñón, Ercilla.
On Saturday 10 June, Luis Marileo and a friend, Patricio Gonzáles, were shot dead in a dispute with Ignacio Gallegos Pereira, the occupier of a large estate and former sergeant with the Carabineros ( National Police). Luis Marileo was a human rights defender working to protect the rights of the Mapuche people. According to an eye witness, the two men had entered the disputed land to recover a horse which had escaped. While Gallegos Pereira claims to have been acting in self defence, medical reports suggest that the two men were shot in the back.
While the Spanish empire never managed to defeat the Mapuche and their territorial rights were recognised under numerous treaties, those rights have been consistently undermined both under the Pinochet regime and following the return to democracy. For years, members of the Mapuche people have reported that they have suffered from police violence, torture and ill-treatment, legal persecution, stigmatisation and criminalisation because of their human rights work.
Anti-terror legislation has been used to target Mapuche activists who are routinely smeared as being involved in violent and criminal activity. The Public Prosecutor's Office has targeted human rights organisations, including Amnesty International, in an attempt to discredit their work to support social organisations and indigenous communities in Chile.
Luis Marileo has a long record of activism defending the rights of the Mapuche people. At the age of 8 he was injured in a police raid on his home. When he was sixteen he was arrested under the anti-terror legislation (the first person to be targeted under this legislation) and spent 7 months in prison, even though he was a minor. He was finally released because there was no evidence to link him to the crimes of which he was accused. In 2013, he was sentenced to 10 years and one month in prison, charged with the murder of landowner Héctor Gallardo, a charge which he always denied. During his time in prison he took part in several hunger strikes to protest at the use of secret witnesses in ordinary civil cases. After three years he was released on provisional liberty.
The killing of Luis Marileo and Patricio Gonzales is consistent with a pattern of entrenched discrimination, defamation and violence against Mapuche activists.
"Ayer fue asesinado Luis Marileo, pero la bala que lo mató fue disparada hace mucho antes, fue disparada desde el momento en que los gobiernos de la Concertación (hoy Nueva Mayoría) y la Derecha, optaron por la criminalización del movimiento, optaron por marcar con fuego las vidas de los niños y jóvenes de comunidad", publicaba Claudio Alvarado Lincopi.
"Yesterday Luis Marileo was shot dead but the bullet that killed him was fired a long time ago; it was fired when the authorities in Concertación (now called Nueva Mayoría) and La Derecha decided to criminalise the movement and to mark out with fire the lives of children and young people in the community", said Claudio Alvarado Lincopi.
Colombia: Failed by the state – HRD shot dead in second attempt on his life
At 7pm on Wednesday, 7 June 2017, Bernardo Cuero Bravo was at home with his family watching a football match on television, when two unknown men arrived at his home in Malambo, Atlántico province. Pretending that they were looking for an apartment that was supposedly for rent in the area, they enticed him out onto the patio where they shot him 4 times in front of his wife. He died instantly.
Bernardo was president of the local Junta de Acción and was also a member of the Asociación Nacional de Afrocolombianos Desplazados (Afrodes). Afrodes represents members of the Afrocolombian community who have been displaced because of the conflict in the region. He was also an active member of the Mesa de Víctimas de Malambo y del Atlántico.
Several years ago Bernardo had survived an earlier attempt on his life. At that time his case was brought to the Inter-American Commission on Human Rights, which instructed the government of Colombia to provide protective measures for him and the other members of Afrodes. He was provided with a bullet proof jacket and a cell phone but a year ago these were withdrawn.
Given the frequent threats to which he was being subjected, Bernardo had repeatedly asked for protection from the state, but this was never provided. Afrodes has lodged numerous complaints about threats against their members in Cali, Cartagena, Bogotá y Soacha.

redpajama_set_name: RedPajamaCommonCrawl


Division IX groups seven IEEE Societies: Aerospace and Electronics Systems (AES), Geoscience and Remote Sensing (GRS); Information Theory (IT), Intelligent Transportation Systems (ITS), Ocean Engineering (OE), Signal Processing (SP), Vehicular Technology (VT). Since 2013 the Division IX Societies have identified a common technical interest in the activities related to the use of technology for improving the Quality of Life of people. In this frame, the Division has recently identified a common topic to work on: Synthesizing Environmental Information (SEI). The scope of SEI is to extract and utilize knowledge on the E-environment in order cope with the environmental issues (global and local scales) with a systematic and timely engineering design approach, and a SoS (System of Systems) framework. One of the goals is also to bring together scholars and practitioners in eScience and in engineering to develop a framework for building an optimal knowledge infrastructure for researchers working on the core scientific issue of earth system dynamics – one which has immense importance for the future management of our planet. The Session will present the topic "Synthesizing Environmental Information", the contributions therein from the Division Societies, the related activities on CollabratecTM and future perspectives.
This event is organised jointly by the European Commission and ESA to present an update of the Sentinel 2A European Copernicus mission and first examples of images acquired in the first month of operations of the satellite. Key international and European users will present their plans for using Sentinel 2 data in the various fields of applications including agriculture, land forestry, wetlands, glaciers and Coastal and Inland waters.
In 2011, and again in 2013, President Obama issued a directive to US Government agencies to identify 500 MHz of the radio spectrum for possible reallocation to the wireless industry. Such a reallocation poses a potential threat to active sensing (satellite SAR, altimeters and scatterometers, as well as radar astronomy and ionospheric radars). Prompted by NASA, the National Research Council established The Committee on Active Sensing to (a) document the societal and environmental contributions of active sensing, (b) evaluate the recent rise in radio frequency interference (RFI) and (c) offer recommendations to US Government agencies. This presentation is a summary of the recommendations issued by the Committee to Government agencies, the scientific community, and the wireless telecommunication industry.
Objective: The focus of this working group is to identify an approach for inter-comparison of data from the three L-band sensors SMOS, AQUARIUS and SMAP leading to merged data sets. This will include definition of techniques and reference sites to be used for this purpose. Initially, some issues fundamental to the understanding of L-Band remote sensing, such as sensor calibration, need to be addressed. In the long run this working group aims toward merged and validated data products using commonly agreed upon standards. It will need to be decided at what level the merging of data should occur (i.e. brightness temperatures or science products such as soil moisture and ocean salinity).
This presentation will introduce the opportunities, which the EU-funded Marie Skłodowska-Curie Actions offer to researchers of all stages to spend some time abroad (Europe and beyond) in order to carry out ground-breaking research. It will guide the audience through the three ways of participating: (i) by applying directly to a vacancy in a project, (ii) by applying for an individual fellowship or (iii) by joining a consortium of European Researchers to exchange staff between different countries and/or sectors (academic and private).
This presentation will introduce the European funding opportunities in the Horizon 2020 programme relevant for the remote sensing community to develop innovative technologies and operational concepts 'from idea to demonstration', using earth observation data for scientific, public or commercial purposes. It will inform the audience about the upcoming calls and rules for applicants on the part of Horizon 2020 focusing on Space Research – Earth Observation, Societal Challenge 7 relating to secure societies and the opportunities for the development of Future and Emerging Technologies.


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Healthy societies
Tackling the challenges of Thailand's aging population
"Thailand's population is rapidly aging and will have a huge impact on all of us." said Siriwan Aruntippaitune, Expert on the Elderly at Thailand's Department of Older Persons (DOP), "Many entities, including the media are frequently raising this topic to the public, however, most of us, especially the working age population, are unaware of the various challenges we are going to face very soon" she continued.
The founding of the DOP in 2015 under the Ministry of Social Development and Human Security of Thailand demonstrates that the Thai government is increasingly taking population aging seriously. Since 2005, Thailand has become an aging society which means 10 percent of its population is over 60 years of age. In addition, the older population grows by around four percent a year as people are living longer, while the birth rate is declining.
In 2015, according to research by the Foundation of Thai Gerontology Research, Thailand has around 11 million aging people, accounting for 16 percent of the population. It is expected that by 2021, the proportion of Thailand's aging population will reach 20 percent, making the country a complete aged society.
Facing the inevitable future
Siriwan stated that health issues are the key challenges for the elderly in Thailand, "We are facing a challenge relating to demand of care for around 200,000 people who have become vulnerable. This group needs special support in their daily lives, relative to their physical condition. Thailand's Ministry of Public Health recently completed the development of its long-term care plan for the vulnerable group and has started developing a concrete policy to manage care manager and caregiver manpower," she said.
Both reactive and preventive care should be implemented simultaneously to tackle Thailand's aging situation in time, according to Siriwan. Health literacy must be promoted widely so that the public are aware of unhealthy lifestyle and nutritional habits that lead to illness. Medical expenses have an effect on not only personal finance but also the country's financial system.
"Most Thai people are still unprepared and lack retirement planning knowledge," Siriwan added, "According to recent data from the Bank of Thailand, Thai Generation Y (18-35 years old) are not equipped to save for retirement. Most are spending more than they earn, leading to debt. If they do not develop solid financial habits, they will face financial issues upon retirement," she said.
Fostering a healthy aging society
To address Thailand's rapidly aging population and its impact on individuals, the economy and society as a whole, Siriwan asked all public and private sectors to join forces.
"All sectors can help by sharing their knowledge and resources to support a long-term care system for the country. The Bank of Thailand and The Stock Exchange of Thailand, for example, have been running a campaign promoting retirement saving. The government-funded OTOP (One Tambon, One Product) has been supporting entrepreneurial efforts to improve their income. Thailand now needs an NGO leader to represent the rights and well-being of the elderly."
To respond to the challenge of Thailand's aging population, The Pfizer Healthy Aging Society Project was launched last year, implemented by Pfizer Foundation Thailand and Kenan Foundation Asia. The project aims to establish a sustainable preventive health care approach for pre-seniors and seniors to support quality aging in Thailand. Siriwan added, "This is a good initiative from Thailand's commercial and NGO sectors. Health literacy building will help improve the quality of life of the elderly, while addressing health issues which are the key challenge for Thailand's aging society today. I believe that the pilot implementation will help us gain new insights to extend the work to other areas in the future."
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... sometimes the story was a tiny little snippet, sometimes it meandered on for quite some time. i tried to capture gestures of each story to keep things mysterious and interesting.
Good stuff! I like that concept!


Karl Tatler Estate Agents & Lettings has won the Feefo Gold Service award, an independent seal of excellence that recognises businesses for delivering exceptional experiences, as rated by real customers.
Karl Tatler Estate Agents & Lettings cleared the criteria of collecting at least 50 reviews between January 1st 2018 and December 31st 2018, with a Feefo service rating of between 4.5 and 5.0. Overall throughout 2019 they collected 871 reviews, with an impressive 4.7 out of 5 achieved.
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I'm trying to do a nested sorting, I have sales based on Category and container...is it possible to get the sales sorted by category..when I do a combined field the sales get sorted with in the group of container and category..is it possible to remove the container from the grouping and just sort based on category from high to low. I have attached a sample workbook.
Hi Michel Caissie Thanks for the reply..but if we do in this we are loosing the grouping right..i meaning the Category is repeated for individual row..is there any workaround to keep the original layout and sort it..once again thanks for the help..
Before going in detailed explanation, is this what you are looking for ?
If not, can you mockup the expected values.
And can you read version 9.3 files ? I don't have your version.


text:
Why is chemistry unpredictable?
Disclaimer: I am not a chemist by any means, and I only have knowledge limited to what I learned in my university's Chemistry III course. Basic understanding of everything up to valence electron orbitals.
Why is there no set of rules to follow which can predict the product of chemical reactions? To me, it seems that every other STEM field has models to predict results (physics, thermodynamics, fluid mechanics, probability, etc) but chemistry is the outlier.
Refer to this previous question: How can I predict if a reaction will occur between any two (or more) substances? The answers given state that empirical tests are the best way we've gotten to predict reactions, because we can discern patterns or "families" of reactions to predict outcomes. Are we only limited to guessing at "family" reactions?
In other words, why am I limited to knowing my reactants and products, then figuring out the process? Can I know the reactants, hypothesize the process, and predict the product?
If the answer is "It's complicated", I would enjoy a push in the right direciton - like if valence orbitals actually do help us predict, or any laws of energy conservations etc, please give me something which I can go research.
physical-chemistry experimental-chemistry theoretical-chemistry process-chemistry
Redwolf Programs
Tyler MTyler M
$\begingroup$ Your best bet would be to look at the field of theoretical chemistry which has various branches of study as highlighted in the above link. Basically, if you are given a set of reactants and products, then you can have a huge number of combinations of atoms simply by looking at all possible arrangments of atoms. But, you can significantly narrow down your options by looking at lower potential paths (which are made from ab initio calculations), simulating movements of the nuclei (molecular dynamics), theoretical kinetics and so on. $\endgroup$
– Yusuf Hasan
$\begingroup$ BTW, just a digression: You said chemistry is the "outlier" in STEM. I have a gut feeling that maybe biology (which is also a part of STEM) may not be "predictive" enough for you as well, at least when you start out with the subject. Biology and chemistry together form an integral part of STEM, so it may be worth pondering over their seemingly "empirical" nature ;) $\endgroup$
$\begingroup$ Chemistry is neither a set of easy rules, neither set of empirical knowledge to memorize. Or, it it both, intertwined in a wild mixture of both extremes. Most non chemists are too impatient to recognize many patterns, that are hybrids of rules and evidence. $\endgroup$
– Poutnik
$\begingroup$ doi.org/10.1016/j.drudis.2018.02.014 $\endgroup$
$\begingroup$ It's not unpredictable. It is just complex... sometimes to a point it is easier to just try (many times) and see instead of calculating something. $\endgroup$
– fraxinus
First of all, I'd ask: what do you admit as "chemistry"? You mentioned thermodynamics as being a field where you have "models to predict results". But thermodynamics is extremely important in chemistry; it wouldn't be right if we classified it as being solely physics. There is a large amount of chemistry that can be predicted very well from first principles, especially using quantum mechanics. As of the time of writing, I work in spectroscopy, which is a field that is pretty well described by QM. Although there is a certain degree of overlap with physics, we again can't dismiss these as not being chemistry.
But, I guess, you are probably asking about chemical reactivity.
There are several different answers to this depending on what angle you want to approach it from. All of these rely on the fact that the fundamental theory that underlies the behaviour of atoms and molecules is quantum mechanics, i.e. the Schrödinger equation.*
Addendum: please also look at the other answers, as each of them bring up different excellent points and perspectives.
(1) It's too difficult to do QM predictions on a large scale
Now, the Schrödinger equation cannot be solved on real-life scales.† Recall that Avogadro's number, which relates molecular scales to real-life scales, is ~$10^{23}$. If you have a beaker full of molecules, it's quite literally impossible to quantum mechanically simulate all of them, as well as all the possible things that they could do. "Large"-ish systems (still nowhere near real-life scales, mind you — let's say ~$10^3$ to $10^5$) can be simulated using approximate laws, such as classical mechanics. But then you lose out on the quantum mechanical behaviour.
So, fundamentally, it is not possible to predict chemistry from first principles simply because of the scale that would be needed.
(2) Small-scale QM predictions are not accurate enough to be trusted on their own
That is not entirely true: we are getting better and better at simulating things, and so often there's a reasonable chance that if you simulate a tiny bunch of molecules, their behaviour accurately matches real-life molecules.
However, we are not at the stage where people would take this for granted. Therefore, the ultimate test of whether a prediction is correct or wrong is to do the experiment in the lab. If the computation matches experiment, great: if not, then the computation is wrong. (Obviously, in this hypothetical and idealised discussion, we exclude unimportant considerations such as "the experimentalist messed up the reaction").
In a way, that means that you "can't predict chemistry": even if you could, it "doesn't count", because you'd have to then verify it by doing it in the lab.
(3) Whatever predictions we can make are too specific
There's another problem that is a bit more philosophical, but perhaps the most important. Let's say that we design a superquantum computer which allowed you to QM-simulate a gigantic bunch of molecules to predict how they would react. This simulation would give you an equally gigantic bunch of numbers: positions, velocities, orbital energies, etc. How would you distil all of this into a "principle" that is intuitive to a human reader, but at the same time doesn't compromise on any of the theoretical purity?
In fact, this is already pretty tough or even impossible for the things that we can simulate. There are plenty of papers out there that do QM calculations on very specific reactions, and they can tell you that so-and-so reacts with so-and-so because of this transition state and that orbital. But these are highly specialised analyses: they don't necessarily work for any of the billions of different molecules that may exist.
Now, the best you can do is to find a bunch of trends that work for a bunch of related molecules. For example, you could study a bunch of ketones and a bunch of Grignards, and you might realise a pattern in that they are pretty likely to form alcohols. You could even come up with an explanation in terms of the frontier orbitals: the C=O π* and the Grignard C–Mg σ.
But what we gain in simplicity, we lose in generality. That means that your heuristic cannot cover all of chemistry. What are we left with? A bunch of assorted rules for different use cases. And that's exactly what chemistry is. It just so happens that many of these things were discovered empirically before we could simulate them. As we find new theoretical tools, and as we expand our use of the tools we have, we continually find better and more solid explanations for these empirical observations.
Let me be clear: it is not true that chemistry is solely based on empirical data. There are plenty of well-founded theories (usually rooted in QM) that are capable of explaining a wide range of chemical reactivity: the Woodward–Hoffmann rules, for example. In fact, pretty much everything that you would learn in a chemistry degree can already be explained by some sort of theory, and indeed you would be taught these in a degree.
But, there is no (human-understandable) master principle in the same way that Newton's laws exist for classical mechanics, or Maxwell's equations for electromagnetism. The master principle is the Schrödinger equation, and in theory, all chemical reactivity stems from it. But due to the various issues discussed above, it cannot be used in any realistic sense to "predict" all of chemistry.
* Technically, this should be its relativistic cousins, such as the Dirac equation. But, let's keep it simple for now.
† In theory it cannot be solved for anything harder than a hydrogen atom, but in the last few decades or so we have made a lot of progress in finding approximate solutions to it, and that is what "solving" it refers to in this text.
orthocresol♦orthocresol
Let me contribute two more reasons which make chemistry hard to analyse from a purely theoretical standpoint.
The first one is that, viewed very abstractly, chemistry essentially relies on the study of geometry in very high-dimensional spaces, and even from a purely mathematical point this can be extremely difficult. An important part of chemistry is bond breaking and bond formation, which is behind most reactions. This turns out to require knowledge of the vibrational modes of a molecule. For a general molecule with $N$ atoms, there are $3N - 6$ vibrational modes. Each of these vibrational modes are a "spatial dimension" in what is called phase space. In principle, if we knew the potential energy in every point of the phase space for a molecule, we would know virtually everything there is to know about how it might react. For an idea of what this looks see, see the figure below:
Source: https://www.chemicalreactions.io/fundamental_models/fundamental_models-jekyll.html
Unfortunately, there is simply too much space to explore in very high-dimensional objects, so it's very difficult to get a picture of it as a whole. Also disappointingly, almost all of this space is "tucked away in corners", so it is also very difficult to get a reliable picture of the whole space by looking at small bits of it at a time. This has been called "the curse of dimensionality". Something as simple as benzene ($\ce{C6H6}$) has a $\mathrm{3 \times 12-6 = 30}$-dimensional vibrational phase space (though this particular phase space is highly symmetric, as benzene itself has a high symmetry). Now consider a general reaction which requires two reagents, and forms one product:
$$\ce{A + B -> C}$$
Each of the three molecules has its own phase space, and combining them all together means adding all the number of dimensions of each. In this view, a chemical reaction is nothing but a particular set of trajectories of points (for each atom) in the combined phase space of all molecules, such that the potential energy of the system is locally minimised throughout the trajectory. As such, one would easily find themselves trying to describe trajectories in objects with over 100 dimensions. Few people talk about chemistry at this level of abstraction because it is so complex, but it is a conceptual hurdle in describing chemistry "exactly". Thankfully, there is research into it, such as the CHAMPS collaboration.
The second complication is that, while many important reactions are direct reactions like the one shown above, in the general case, what really exists is a network of reactions, potentially forming a complicated, highly interconnected graph with dozens or even hundreds of intermediates and possible products (graph vertices) and as many reaction arrows connecting them (graph edges). The field of chemical reaction network theory uses graph theory to study these networks. It appears that some of the problems they grapple with are NP-hard.
Source: https://www.mis.mpg.de/stadler/research/chemical-reaction-networks.html
Of course, this second issue compounds on the first!
So given these two dizzyingly complex problems, even from a purely mathematical standpoint, how can we do chemistry at all? Well, with enough experimental parametrization (e.g. equilibrium constants, rate constants, enthapies and entropies of formation, etc.) and approximations, you can drastically simplify the description of a system. Fortunately, even after throwing away so much detailed information, we can still make decent predictions with what is left. You really should count ourselves lucky!
Nicolau Saker NetoNicolau Saker Neto
$\begingroup$ This is a really insightful and absolutely fantastic answer and extremely helpful to those outside of or not immersed in chemistry. I see stable manifolds in satellite trajectories and in papers about them in Chaos but never stopped to think of how general the concept was. Instead of doing what I was supposed to today I will go hide somewhere and (try to) read all of your linked sources :-) $\endgroup$
$\begingroup$ @uhoh There are a number of articles studying chemical oscillators (which can display mathematical chaos) from a reaction network theory perspective. That alone is probably quite a rabbit hole to go down. You have my blessing! $\endgroup$
– Nicolau Saker Neto
$\begingroup$ And all of that only to describe reactions that occur on 1 electronic state. Photo-induced reactions can involve multiple electronic states which also requires accurate description of the coupling of all states. $\endgroup$
– Hans Wurst
Parts of chemistry have predictability but the combinatorial complexity of what is possible leaves a large amount of space for things that don't follow the rules
Some of the ways chemistry differ from physics in unpredictability are an illusion. Take gravity, for example. There is a strong rule–sometimes described as a law–that all objects near the surface of the earth fall with the same acceleration. That is a cast iron rule isn't it? Apparently not. Flat pieces of paper and feathers don't fall as fast as cannon balls and the exact way they fall is very unpredictable. "But we know why that is, don't we?" Yes, a bit, it is air resistance. But that doesn't enhance the predictability at all as any useful prediction would have to solve the equations for fluid flow and there is a $1m prize for even proving that those basic equations even have a solution all the time.
Arguably, physics is only predictable in school where only idealised versions of real problems are considered.
And it is unfair that chemistry is completely unpredictable. A good deal of physical chemistry is quite like physics in its laws and predictions.
I suspect that you are talking about general organic and inorganic chemistry where there are many predictable properties of compounds but a dictionary full of exceptions to even simple rules.
Or synthetic chemistry where reactions sometimes work but often don't. But, there are plenty of chemical reactions that work fairly reliably (Grignard reactions make C-C bonds fairly reliably with many compounds; Diels Alder reactions create two at once with predictable stereochemistry.)
But this predictability is limited by a fundamental problem: the unfathomably large variety of possible compounds that could be made. Take a ridiculously small subset of possible compounds: all those that can be made just from carbon and hydrogen using only single bonds and disallowing any rings. For simple compounds where the 3D nature of the compounds does not interfere by constraining their existence in real space (atoms have finite volumes in 3D space and can't overlap in real structures) these are mathematically equivalent to simple trees (or the carbon skeleton is: we assume the hydrogens fill out the remaining bonds so each carbon ends up with 4). at the point where 3D space becomes a constraint on which can exist, there are already about 25k distinct possible compounds and by the time you get to 25 there are more possibilities than all the chemicals that have ever been characterised in the history of chemistry.
And this is for very constrained rules for making the compounds that use only two elements and deny a huge variety of interesting structures.
The real issue making chemistry apparently complex is that unfathomably large combinatorial variety of possible chemicals that might exist. In such a large space there is very little possibility that simple rules will always work. And this complexity is just about the possible structures. There are a very large number of reactions that get you from one structure to another and those add another midbuggeringly large layer of complexity.
And this, I think, is the reason why many find chemistry so hard to generalise about. There are simply too many possible things that can exist and even more possible ways to make them for any simple set of rules to always work. And I thought physicists had a problem not being able to fully solve the Navier Stokes equations.
Predictabilty is essentially determined by the level of detail you need to accurately model the phenomenon you're trying to predict. Models that require little detail to capture the phenomenon of interest typically can give reliable predictions, while those requiring enormous detail typically cannot.
The level of detail needed is determined by the complexity of the system, and the fineness at which you wish to model it; the amount of detail needed to model a complex system can be reduced if you only wish to make coarse-grained predictions.
This is true for all the sciences—biology, chemistry, physics, and geology. Thus, in this fundamental way, they all have the same predictability. I.e., there is no fundamental difference in the nature of prediction among these fields. Allow me to illustrate:
Physics:
Bending of light from a distant star by the sun's gravitational field. Predictable. Requres very little detail to model the phenomenon accurately: Just the mass of the sun, and the assumption that the distant star is a point particle at a distance much greater than the earth-sun distance.
The temperature of the sun's corona. Not yet predictable. This problem requires far more detail to model correctly. The system is so complex that we don't have a model to predict the temperature of the sun's corona, and thus can't explain why the corona is far hotter than the surface of the sun.
Chemistry:
Osmotic presure of a highly dilute solution. Predictable. Requires very little detail to model the phenomenon accurately: Just the concentration of the solute.
Folding of long (1000's of nucleotides) RNAs. Coarse-grained predictions (the relative radius of gyration) can be made; fine predictions (the ensemble-average probability of each individual base pair) cannot be made (at least not reliably).
Biology:
Possible blood types (O, A, B, AB) of offspring, and their odds. Predictable. Requires only the blood type of each parent.
Size at which cells divide. Not yet predictable. Cells are enormously complex, and thus a model capable of predicting this would require enormous detail.
Granted, there is a practical difference among the fields, in that physics has more phenomena that can be predicted with simple models than chemistry, and chemistry more than biology, because as one goes from physics → chemistry → biology, one is typically studying successively higher levels of organization of matter. But I regard that as practical difference rather than a fundamental one.
theoristtheorist
$\begingroup$ Reminds me of Rumsfeld's famous "known unknowns and unknown unknowns". Another classic example: the weather. In some cases it is not detail that matters (nonlinear dynamics), in fact accurate simple models can fail to provide useful predictions even when all parameters are known exactly. $\endgroup$
– Buck Thorn ♦
"it seems that every other STEM field has models to predict results (physics, thermodynamics, fluid mechanics, probability, etc) but chemistry is the outlier"
This is only partially true, but there are areas of all of those fields where predictive power is difficult in practice due to the complexity of the system and convolution of features. In simplified cases, yes, we can do quite well, but once the systems grow in size and complexity, we do less well.
Physics is a good example of this. The laws of mechanics are quite well-understood. But how well can you handle a chaotic 3-body system? There may be features that are predictable, but not probably not the entire system.
With thermodynamics, how well do we handle mesoscopic systems? Computationally, they can be quite difficult. In thermodynamics, we're able to deal with this complexity by discarding features that we don't care about to focus on bulk properties that rapidly converge in ever-larger systems, but we can't handle the entire system.
Fluid mechanics. OK. We have Navier-Stokes. Have you tried solving Navier-Stokes? Entire volumes have been written about how to deal with Navier-Stokes, and we still don't have great understanding of all of its features.
Probability. This is trickier to talk about, but I think the difficulty and complexity is building an underlying probabilitistic model. When you build your machine learning model, there are generally hyper-parameters to set. What makes a good hyper-parameter and how do you pick one? Just the one that works?
The thing with chemistry is that real-life examples are already incredibly complex. Pick any reaction you want. Liquids or solids? You're already dealing with bulk properties, phase interfaces, and boundary effects. Or solutions and solution effects. Gases? Once you have non-trivial reactions, how many atoms are there? How many electrons? Now, consider the fact that your typical organic reaction involves compounds with tens or hundreds of atoms in solution. There may be multiple models of reactivity, some productive, some not. And in the laboratory, reactions can be quite sensitive to any number of reaction conditions, which a generalized reactivity model does not begin to account for.
But in chemistry, as with the other disciplines, we aim to find simplifications that allow us to deal with complexity. We've been able to find patterns of reactivity, which are somewhat general but don't capture the full complexity of the system.
ZheZhe
There are some great answers to this question already, but I'd like to provide a more practical boots-on-the-ground answer from my own perspective as an organic chemistry PhD who did computational chemistry on the side.
Most fields at their cutting edge are unpredictable
It has been my observation that when you come up against the frontier of what is possible, progress comes by and large only through a long grinding process of Trial and Error. When a breakthrough in understanding is made and the process all of a sudden becomes easy, rapid progress is made until things become hard again. This is true of all sorts of complex projects. The theory helps you along so far, but at some point you have to go off the beaten track and make your own way.
Chemistry gets mathematically hard, fast
Someone who's completing their undergraduate in a STEM field is likely to have a bit of a skewed impression of the first fact, because they will have already reached that point of unpredictability with chemistry but not with physics. It takes a long time to learn the differential equations associated with things like mechanics, stress-strain, heat transfer, fluid dynamics, electromagnetism and quantum fields. These topics often have solutions for idealised situations that are amenable to being written on paper in closed form.
The (comparative) simplicity of these solutions along with the difficulty of learning the necessary maths along the way may give the undergrad physicist the mistaken idea that this is what all physics is like. Hard-but-tractable differential equations that yield elegant solutions. In reality once you get past the idealised conditions physics becomes much more about computer simulation and experimentation.
In contrast, the equations that describe what happens in the flask (kinetics and thermodynamics) go from trivial to mind-bendingly difficult with only a little bit of added complexity. Other answerers have gone into this part in more detail, so I won't talk but about it here. Suffice to say I spent many fruitless hours of my education trying to find a generalised maths approach to the problems I was facing.
In practice, at least for organic chemistry, the main objective is to synthesise compounds from other compounds, typically complex ones from simple ones. The theory sort of devolves into a broad, massive decision tree.
Want to make intermediate A? try reaction B, if that doesn't work try reaction C. C normally works for this kind of thing, so if it's not working, check that your reagents are pure. You could try D but that's likely to deprotect the other side of A.
Systematic studies of certain reaction patterns exist, and they can certainly be helpful. Take the substitution patterns of aromatic rings, for instance. Using a bit of orbital theory, you can predict the outcome of reactions on aromatic rings based on what's already on the ring and in what position. But again, these studies were done on simple substrates and may not necessarily apply to whatever synthetic behemoth you're working on.
Lab work is hard
Finally on to the practical aspect. Chemical reactions may fail for any number of reasons that aren't theoretical. There's basic stuff like the cleanliness of your equipment and the purity of your reagents. You can lose heaps of your material by choosing the wrong solvents to work up (extract the product from the reaction mixture) with. Most of the material has gone into the aqueous layer without you knowing it, and you've either discarded it (rookie mistake) or it's degraded or turned into something else before you realised.
Then there's the more subtle stuff. The reaction might only work with one particular stir bar because it was impregnated by a palladium catalyst at some point. Reactions often need rigorous exclusion of oxygen and water to work, but occasionally you actually need some oxygen present to make it go, and the only way you'd ever find this out is by noticing the sloppily set up reactions always seem to perform better than the rigorous ones. You have one bottle of reagent from the sixties from a company that no longer exists, and once that's used up, the new bottle of the same reagent just doesn't work (this one happened to me). The surface of your glassware is slightly too acidic for your reaction, and you need to silanise it to get it to work (also happened to me). Some reactions don't work because your country is just too damn humid. The procedure you're following was written by a student desperate to impress/placate their adviser, and the yields are inflated. Your current lot of acetonitrile solvent is lower quality because China shut down their polluting acrylonitrile plants in order to improve the air quality in preparation for the Olympics. And so on and so forth.
Chemistry as a subject is very bitsy and messy. The best chemists I've known often had excellent memories. But all subjects tend to be messy and bitsy once you get past the basic theory and into the fine details.
IngolifsIngolifs
To me, it seems that every other STEM field has models to predict results (physics, thermodynamics, fluid mechanics, probability, etc) but chemistry is the outlier.
What about structural engineering? Within that field, it's quite easy to predict the strength of a beam of known material and dimension, like a steel I-beam or dimensional lumber. But what about some new material, like a composite of toothpicks embedded in Elmer's glue?
Whether the material is steel or toothpick-glue composite, couldn't one "just" predict the strength from more basic physical properties?
Well yes, but that would be very complex. But I think more importantly, that wouldn't be structural engineering anymore. It would be some more basic field of physics.
You argue chemistry is "unpredictable" because reactions are described by rules and patterns rather than being derived from first principles. I posit these rules and patterns are chemistry. Without them, you no longer have chemistry. So chemistry is "unpredictable" (in your sense) by definition.
This isn't unique to chemistry, really. Most fields of study are based on the application of more pure fields, adding their own rules and patterns to enable higher-level reasoning about more complex systems:
Phil FrostPhil Frost
The answer is dimensionality reduction: a reaction has billions and billions of atoms interacting with one another, but we create analogies to the interactions using just a few symbols which we manipulate using rules; a symbolic analogy of countless atoms interacting, but this process implies loss of information about reality. The simpler the analogy, the higher the loss of information and the less accurate the analogy. The results of symbol manipulation will differ from the reality of the reaction. The average of a set of numbers is a good example: you reduce a set of n dimensions onto a single dimension. There is a loss in information.
Another example: Newtonian physics did not predict what scientist saw with the famous Double Slit experiment. The moment that happens, the rules and symbols you use to make predictions(like the yield of a chemical reaction) become useless. So, it's not that Chemistry is unpredictable, the symbols we use to make predictions about chemistry are not good enough. The only way to make 100% accurate predictions is to simulate every single atom and subatomic particle and be certain the rules we use to define the interactions are 100% analogous to what happens in reality. We know this to be impossible due to the uncertainty principle.
Quantum chemistry has much more complex models that are a better analogy to a reaction, thus it is a *better predictor, but never 100% accurate.
Any basic text in Organic Chem has a table of contents.So for a given transformation such as reduction it will list reagents( the chemicals or conditions,eg heat ,light,that appear above the arrow connecting reactants with products) For a simple reactions such as the sodium borohydride reduction of acetone to isopropanol I have absolute faith that if I carry this out in the laboratory it will work.If it didn't work I would check the labels on the reagent bottles and confirm the identity/purity of the chemicals used.If these checked out and the reaction still failed ,it would be in the category of dropping an apple and watching it ascend up toward the sky.It is not a matter of a failed opinion.Now if I change the substrate to a large polyfunctional molecule,the analogous reduction may not occur at all or yield a highly rearranged product.Retroanalysis may provide a rationale but for the bench chemist doing the reduction,it is an opinion as to whether it is worth trying the reaction in the first place.
Bob MoriartyBob Moriarty
Simply put, it is because we don't have complete or near complete understanding of the forces that drive chemical reactions, every few atoms added to the structure of the compounds will add new forces and layers of complexity that we haven't accounted for in our simple 300 years of chemistry knowledge. You can sense this when you learn the theories show their limitation at some point where complexity surfaces (for instance Lewis, Huckel ... etc).
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Dare To Lead Buddy Read Discussion. This is further proof that sometimes finding the intersection of two very different reading tastes doesn't have to be difficult! @definitelyra suggested we read this one, and she knows us well. Curtis loves leadership books, and Chelsey has read some @brenebrown. Listen to our conversation to find out what we thought of the book and how we might apply the concepts for ourselves.
Announcement: We're releasing two episodes in April, 4/9 and 4/23 because we're prepping to move. Then we'll be on hiatus for the month of May. We'll still post Patreon content here.


Last fall I was asked by my sister to do the bridal portraits her sweet, soon-to-be daughter-in-law. It is a tradition in the South to have bridal portraits shot months before the wedding, and have one or more of the portraits on display at the wedding reception.
I have shot one wedding, but never a bridal portrait. I really wanted to say no, but I eventually gave in and tried to approach it as a learning experience I could share here at EE in the future.
This post is not about prepping for a bridal portrait shoot, or all the things I learned from the experience. Instead I want to focus on one particular shot and share what I did to capture it.
The church was small and quaint, but it did not have a large variety of places to pose the bride. I had not seen the church before (they live five hours away from me), so I had to think on my feet.
There was a large doorway at the front of the church, with some lovely colors in the background. I decided to pose the bride in the middle of it, and have her turn to look back at me. When I shot without flash, I metered for her and could get a nice shot, however it blew out (extremely overexposed) the foliage behind her. Thankfully I had brought my flash and a slew of reflectors.
I positioned my sister behind me, holding the reflector in the air a bit. My Nikon SB910 flash was put on the camera and turned to point at the reflector. When the shutter was released and the flash fired, the light bounced off the reflector and onto the bride.
Why bounce the flash and not point it right at her? By bouncing the flash off the reflector, it softened the light and prevented harsh shadows that often come with direct flash.
Below is one of the shots taken in that position. It is pretty much straight-from-camera (I did pull down the highlights in Lightroom to recover some clipping). Notice the carpet of the church, then the wood of the deck outside.
UNEDITED image to show true background and location.
The image at the top is one that was printed for the reception. I editing in Lightroom, then Photoshop Elements. You can see I removed/covered the driveway that was behind her. Next is an Instagram shot of the other portrait she had at the reception. I will talk about that shot in a separate post.
Below is an graphic showing where I was in relation to the bride, and where my sister was with the reflector. The graphic is NOT to scale. 😉 If you are brand new to the world of flash, check out the beginners guide to using flash post I wrote a while back.
This was very useful, I have used flash to lift the light or maybe fill in the light or balance the light with a bright background but bouncing the flash from behind me is something I am going to practice right away! Thanks for sharing!
Thanks for this, Amanda! The finished portrait is lovely. Would you consider doing an editing tutorial for us? I would love to see how you successfully covered up the driveway to the right of her. Yours looks so natural-mine always looks botched up!
Mindy, I just did a quick tutorial showing the same technique I used to remove the driveway. Hope it helps.
Please so a video demonstrating cloning and cleaning up a scene. I have the worst time blending in a cloned area.
Jennifer, I just did a quick tutorial showing the technique I used I removed the driveway. Different picture, same steps. Hope it helps.
I have never thougth of using the reflector like that! Did you use a white reflector so that the light stayed soft?
Adn your edit is beautiful! I read the article about fillping the background, what a time saver!!
How did you allow for the beautiful ambient light?
Thank you. I love all your tutorials and help!


The surrounding wall of the Tomb is 500 meters long and it is almost a perfect circle. The diameter of the Tomb is 158.4 meters and this is the standard of Deinokratis. It was him that constructed the walls of Alexandria, which are 15.840 meters long. This beautiful surrounding wall, which is almost intact, reaches 3 meters high and is covered by cornice. The marbles come from the island of Thassos.
More than 500 missing pieces from the surrounding wall have been found near the place where the Lion of Amphipolis sits. More than 100 stones were discovered just a couple of days ago in Lake Kerkini, where the pieces were transferred in 1936 by the company Ulen, who were in-charge of the construction for the Dam at Kerkini.
The marble of the Wall was brought from the island of Thassos and is in almost perfect condition.
The photo depicts the base of the wall, the blocks of marble and the base of the wall, just behind the wall. It's impressive to look at the top, to realize the actual depth of the excavations.
The surrounding wall is covered by an amazing cornice which looks almost intact, even if it was constructed 2.300 years ago.
As we can see in the photo, the perimeter consists of multiple levels of stone. Total height of the perimeter wall is 3 meters.
Photographers are covering the visit of the Greek Prime Minister.
Photo taken during the excavations of the 500-meter perimeter wall of the tumulus.
Large blocks of white marble are surrounding the tomb of Amphipolis.
The wall consists of limestone blocks clad in marble. The marbles come from Thasos, an island of North Aegean. It's the same type of marble used for the sculpture of Lion of Amphipolis.
Part of the high wall (3 meters height, 500 meters circumference), during the early excavations in 2013.


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JAEY'S COURSE UPDATE APRIL 2021
JAEY'S COURSE UPDATE, APRIL 2021
Spring greetings from the Golf Course as April passes by. As ever I will start with the weather, the main driving force behind everything happening out there. Spring usually throws a curve-ball at us, some years it is hot and dry like 2020, others we have ferocious winter storms like 'The Beast from the East' in 2018. This year we have had a cold, dry spell running for the entire month.
The monthly rainfall total was sitting on 1mm until 28 April when we had 14mm overnight before a further 9mm later in the day giving us a month total of 24mm, under half our expected figures for the month. In addition to this, the predominant wind direction was either easterly or northerly which always brings dry, cold air to us from beyond Scandinavia. The result of these systems was an unprecedented run of frosty mornings, a total of 22 out of the 30 days of April. The BBC reported that 2021 was the frostiest April for 60 years.
Now, these conditions are not really conducive to growing most plants, so it has been a challenging spell particularly on surfaces that we have been trying to push a bit of growth into for recovery from winter. The good news is that regular inputs of basic nutrition have been facilitating some slow growth and decent recovery from both winter damage and current traffic as the afternoon temperatures start rising. The positive point about the weather conditions of April has been the amount of high-quality sunlight available to the plants, benefitting both plant metabolism and soil temperatures in the pm hours.
We have left the greens height of cut at 5mm for the month to keep any further stress on the turf to a minimum but as overnight temperatures start to rise we will reduce this by half a mm at a time before settling in at 4mm for the season. Our main challenge at the moment is growing out the moss that has been treated and is currently sitting quite stressed. As growth picks up the existing turf plants will push through and fill in these patches with strong turf colonies. All fertility so far has been through liquid feeds but as soon as soil temperatures rise, we will be applying a granular feed which will give them a push along.
To a lesser degree, poa seedhead season is almost upon us but as our bentgrass proportions have risen this is becoming less of an issue than a few years ago. The greens will look patchy as the poa produces white seeds and it will lose some of its foliage colour as this process follows through.
Culturally we will continue regular grooming with the verticutting units, twice-weekly rolling for smoothing and maintaining our height of cut. Until then we have no option but to have patience and wait for the weather to work in our favour.
ACADEMY BUNKERS
April has presented us with a golden opportunity to undertake some other work while growth has been slow and the team have renovated three of the Academy bunkers by renewing the drainage, rebuilding the edging and renewing the sand. Our bunker sand supply has been very unreliable with supply disrupted by heavy rainfall flooding quarries in October and December and then by equipment failure at the quarry subsequently. In response to these issues, I have sourced an alternative sand to trial, and this has been used in the Academy bunkers.
The 3rd greenside bunker on the Academy has had a major re-shape to accommodate teaching with both more flat base for shot making and more sand face to catch sand splash and reduce the impact on the banking and the green surface.
Finally, please keep an eye on your pitchmarks and repair as many as you can, we have had very high levels of pitchmark damage over the last month. Great to see everyone out on the course again, fingers crossed for a positive future.
Yours in sport,
Jaey Goodchild
Head Greenkeeper


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Young star Amy Carter becomes fifth Thunder signing
By Manchester ThunderIn 2019 SquadPosted September 11, 2018
Amy Carter has signed a two-year contract, keeping her at Manchester Thunder until 2020.
The 19-year-old had a breakthrough season in the Black and Yellow dress in 2018, putting in a number of Player of the Match performances for the senior side.
Carter, who is currently studying medicine at university, was also named u21 Coaches' Player the Year.
The centre-courter capped off a successful season, personally, with a call-up to the England Roses Fast5 squad.
Amy said: "I'm really pleased to sign for the next two seasons with Thunder.
"I really want to push on, make the final and win the whole thing this year.
"I'm looking forward to seeing all the brilliant Thunder fans out there again next season."
Manchester Thunder managing director Debbie Hallas is pleased to have a young talent commit her future to Thunder.
"Amy Carter has already been with the club for a number of years and we have watched her develop into a fine young player," Debbie said.
"She had a great season for us last year and really showed what she can do on the court.
"We are looking forward to seeing her game improve even further and it's a testament to her ability and character to see her get the call-up to the international squad."
KT returns for 10th season
Thunder sign Rebekah Airey from Loughborough Lightning


WLS555 Onboard Weighing System – Scale and Control Inc.
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What is your go-to outfit for summer? Our stylists loves to experiment with prints and bright colors, so we wanted to offer them something completely edgy. If you already own some of the classics, try out something a little different. From classic baby blue and white pinstripes, to edgier monochrome plaids, we picked out some pieces that will suit anyone at any budget.