<p>My guess is that the most likely mechanism would be something like a world-war/pandemic that temporarily prevents astronomers from analyzing sky surveys and/or prevents planetary defense strategies AND a large asteroid/rogue planet that could destroy the Earth. Obviously both of these are extremely low-probability but I suspect that even their intersection would be the most likely mechanism.</p>
<p>And here's some poor quantification for you:</p>
<p>Suppose some of these disastrous wars/pandemics were: COVID-19, Spanish Flu, Black Plague, World War 1, and World War 2. They average around 3 years each, so during human history, about <span class="math-container">$(3 \text{ yrs/disaster}) * (5 \text{ disasters}) = 15 \text{ yrs}$</span> have been spent in extreme disaster. I know these numbers are very rough estimates but for a question like this, you can't expect much precision. I'll also suppose human history started around 200 000 years ago. Then,</p>
<p><span class="math-container">$$P(\text{war/pandemic})\approxeq 15/200000 \approxeq 7.5 \times 10^{-5}$$</span></p>
<p>Furthermore, let's suppose the only giant-impact in Earth's history was the moon formation event. Also, if the Earth is 4.5 billion years old, it is <span class="math-container">$(365)(4.5 \times 10^9) \approxeq 1.6 \times 10^{12}$</span> days old. Then,</p>
<p><span class="math-container">$$P(\text{earth destruction}) \approxeq 1/1.6 \times 10^{12} \approxeq 6.1 \times 10^{-13}$$</span></p>
<p>Therefore, <span class="math-container">$$P(\text{war/pandemic} \cap \text{earth destruction}) \approxeq (7.5 \times 10^{-5})(6.1 \times 10^{-13}) = 4.6 \times 10^{-17}$$</span></p>

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2023-04-03T14:29:59.970Z
Thanks Thomas.  I was initially thinking in answers for "tomorrow", where "today" is March/April 2023, but I certainly agree that averaging "today" over the near future (e.g. the next 100 years) where disasters may happen, as you have effectively done, is also a reasonable approach and very interesting.  Given the huge uncertainties, I am very happy with very rough order-of-magnitude estimates.
David Bailey
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2023-04-07T05:09:12.880Z
I tend to agree with overall concept of this answer, but the probabilities need more work.  It could be argued that two **world** wars, & very destructive ones at that, & pandemics are features of only the 20th Century. The Black Death Plagues, affected large areas over significant time periods, but they weren't global pandemics during a particular era. Also, pandemics rely on large numbers of people moving global with ease & speed over short time spans.  Applying any statistics specific to the 20th Century for the period that homo sapiens have been extant is incorrect. ...
Fred
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2023-04-07T05:12:31.053Z
Moon forming, nearly Earth destroying events, OK, but what about Chicxulub meteor type events (the so called dinosaur killer), or even smaller ones wiping out a locality?
Fred
CC BY-SA 4.0
2023-04-07T14:17:35.137Z
@Fred the meteor would have to "destroy the Earth" as per the specifications provided in the question so it excludes events where localities are wiped out. I agree that it's inaccurate to apply recent world-wide catastrophes to the entire duration of human history but then again, planetary defense systems have only existed for about 10 years, so there's really not a large enough sample size to estimate a probability with much accuracy anyways. I was erring on the safe side and trying to underestimate the probabilities.
Thomas
CC BY-SA 4.0
2023-04-03T13:54:50.750Z
2023-04-03T13:54:50.750Z
Thomas
<p>I have thought a bit more about possible mechanisms that might &quot;stop the sunrise&quot;, so I am posting my own incomplete answer in case anyone might find it pedagogically useful.</p>
<p><strong>Supervolcano</strong></p>
<p>I confirmed onthat an unexpected supervolcano eruption could not block the sun by tomorrow.  Although there is <a href="https://doi.org/10.1038/s43017-021-00191-7" rel="nofollow noreferrer" title="No single model for supersized eruptions and their magma bodies., Wilson, C.J.N., Cooper, G.F., Chamberlain, K.J. et al.  Nat Rev Earth Environ 2, 610–627 (2021)">no single model for supervolcanoes</a>, the time taken for magma to gather is far longer than a day. Also, even if a single supervolcano could unexpectedly erupt, it would take more than a day for its ash to cloud the entire Earth. For example, after the <a href="https://en.wikipedia.org/wiki/Chernobyl_disaster" rel="nofollow noreferrer">Chernobyl disaster</a>, it <a href="https://doi.org/10.1016/0265-931X(88)90055-0" rel="nofollow noreferrer" title="On the transport of Chernobyl radioactivity to eastern Canada, J.-C. Roy, J.-E. Côté, A. Mahfoud, S. Villeneuve, J. Turcotte, Journal of Environmental Radioactivity, Volume 6, Issue 2,1988, Pages 121-130">took almost two weeks</a> for the radioactive cloud to reach eastern Canada.</p>
<p><strong>Asteroid Impact</strong></p>
<p>Unlike a supervolcano, a single asteroid impact could cloud the entire Earth's atmosphere within a day because hot ejecta rains down over the entire planet, setting fires and vaporizing water. It is <a href="https://doi.org/10.5194/acp-16-13185-2016" rel="nofollow noreferrer" title="Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact, Toon, O. B., Bardeen, C., and Garcia, R.:, Atmos. Chem. Phys., 16, 13185–13212, 2016.">estimated</a> that the gases and ejecta from the 10 km <a href="https://en.wikipedia.org/wiki/Chicxulub_crater" rel="nofollow noreferrer">Chicxulub impactor</a> covered the globe within hours.  It might take a few days for a 1 km impactor.
Taking human crises into account, @Thomas's very rough <a href="https://astronomy.stackexchange.com/a/53305/47727">order-of-magnitude estimate</a> of <span class="math-container">$\sim 10^{-17}$</span>/day risk averaged over the the near future seems reasonable. Since a Chicxulub impact is sufficient, however, I think the appropriate impactor time scale is closer to 100 million years than Thomas's 4.5 billion years, giving <span class="math-container">$\sim 10^{-15}$</span>/day risk. Pretty much all answers for this question must be <a href="https://en.wikipedia.org/wiki/Fermi_problem" rel="nofollow noreferrer">Fermi estimates</a>, so a factor of two uncertainty difference in the exponent is not really significant. The answers to <a href="https://astronomy.stackexchange.com/q/39837/47727">&quot;How early could we detect an asteroid the size of the one that caused the extinction of the dinosaurs?&quot;</a> illustrate some of the challenges in estimating how much warning we might have.</p>
<p>Failures due to human crises aside, there might be some impactors that would be tough to detect, but I haven't been able yet to make a quantitative odds estimate:</p>
<ul>
<li>Interstellar objects might be missed even if current detection networks are working well. <a href="https://en.wikipedia.org/wiki/%CA%BBOumuamua" rel="nofollow noreferrer">ʻOumuamua</a> was <a href="https://astronomy.com/magazine/2020/02/our-first-interstellar-visitor" rel="nofollow noreferrer">only detected</a> a week after its closest approach to Earth, but it was likely too small to be a sunrise stopping impactor.</li>
<li>A group of smaller co-travelling objects (perhaps produced in an earlier asteroid-asteroid collision?) might be harder to detect and require less total mass to cloud the Earth if the impacts were spread over the globe.  This would be similar to <a href="https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9#Impacts" rel="nofollow noreferrer">Comet Shoemaker-Levy</a> that was a 21 piece &quot;freight train&quot; that hit Jupiter over several days.</li>
</ul>
<p><strong>Primordial Black Holes</strong></p>
<p>If <a href="https://en.wikipedia.org/wiki/Primordial_black_hole" rel="nofollow noreferrer">primordial black holes</a> exist, the probability of one colliding with the Earth is <a href="https://doi.org/10.1093/mnras/stab2239" rel="nofollow noreferrer" title="Possibility of primordial black holes collision with Earth and the consequences of this collision, Sohrab Rahvar, MNRAS 507, 914–918 (2021)">estimated by Rahvar</a> to be
<span class="math-container">$$\frac{dN}{dt} \approx 10^{-8}f\left(\frac{M}{10^{23}\mathrm{gr}}\right)^{-1}\mathrm{Gyr}^{-1}
\sim10^{-30}f\left(\frac{M_\odot}{M}\right)\mathrm{day}^{-1}$$</span></p>
<p>where <span class="math-container">$f$</span> is the fraction of dark matter made of mass <span class="math-container">$M$</span> primordial black holes, and <span class="math-container">$M_\odot$</span> is the Sun's mass.
For the <span class="math-container">$0.0001 M_\odot$</span> mass primordial black hole mentioned in the question, <a href="https://doi.org/10.48550/arXiv.2002.12778" rel="nofollow noreferrer" title="Constraints on primordial black holes,Bernard Carr et al 2021 Rep. Prog. Phys. 84 116902">Carr et al estimate</a> and upper bound of <span class="math-container">$f\lesssim 10^{-2}$</span>, giving
<span class="math-container">$\frac{dN}{dt} \lesssim 10^{-28}\mathrm{day}^{-1}$</span>, considerably less than the asteroid impact probability above.</p>
<p><strong>Sun going dark</strong></p>
<p>Although this question is primarily about <em>mechanisms</em> that could unexpectedly destroy the Sun or the Earth or block the sunlight, it is interesting that there is a current ongoing research project that simply looks for stars that disappear.
The <a href="https://vascoproject.org/" rel="nofollow noreferrer" title="Vanishing &amp; Appearing Sources during a Century of Observations">VASCO project</a> has recently searched for <a href="https://vascoproject.org/vanishing-stars/" rel="nofollow noreferrer">vanishing stars</a> and other astrophysical objects that may have disappeared.  Based on <a href="https://doi.org/10.1093/mnras/stac1552" rel="nofollow noreferrer" title="Discovering vanishing objects in POSS I red images using the Virtual Observatory, Enrique Solano, B. Villarroe and C. Rodrigo, MNRAS 515, 1380–1391 (2022)">5399 sources</a> that disappeared over <span class="math-container">$\sim$</span>70 years out of <a href="https://doi.org/10.3847/1538-3881/ab570f" rel="nofollow noreferrer" title="The Vanishing and Appearing Sources during a Century of Observations Project. I. USNO Objects Missing in Modern Sky Surveys and Follow-up Observations of a Missing Star, Beatriz Villarroel et al., The Astronomical Journal, 159:8 (19pp), 2020 January">600 million objects</a>
from the United States Naval Observatory (USNO) B1 catalog, the naive disappearance rate is <span class="math-container">$4\times 10^{-10}$</span>/day.
This is much higher than the undetected asteroid impact rate above, but it isn't a very helpful number since most (and perhaps all) of these disappearances are for sources unlike the Sun, and we expect that most (and likely all) are due to known processes e.g. <a href="https://en.wikipedia.org/wiki/Failed_supernova" rel="nofollow noreferrer">failed supernova</a> or observation artifacts. <a href="https://doi.org/10.1038/s41598-021-92162-7" rel="nofollow noreferrer" title="Exploring nine simultaneously occurring transients on April 12th 1950, Villarroel, B., Marcy, G.W., Geier, S. et al. Sci Rep 11, 12794 (2021)">Some of the disappearances</a> and the <a href="https://www.youtube.com/watch?v=X3xddkS4H80" rel="nofollow noreferrer" title="Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?, Anton Petrov, YouTube, 24 Sep 2021">sheer number</a> seem hard to explain, but the data are not yet well enough understood to set limits on specific classes of stars.</p>

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2023-04-06T14:57:32.217Z
2023-04-08T15:25:38.487Z
2023-04-08T15:25:38.487Z
David Bailey
<p>What is the most likely natural astrophysical mechanism for the &quot;Sun not rising tomorrow&quot;, consistent with our scientific knowledge today?</p>
<p><strong>Background</strong></p>
<p>The &quot;<a href="https://en.wikipedia.org/wiki/Sunrise_problem" rel="nofollow noreferrer">sunrise problem</a> - <em>What is the probability that the Sun will rise tomorrow?</em> -
is a classic probabilistic conundrum <a href="https://www.jstor.org/stable/41133850" rel="nofollow noreferrer" title="Buffon, Price, and Laplace: Scientific Attribution in the 18th Century. S. L. Zabell, Archive for History of Exact Sciences, vol. 39, no. 2, 1988, pp. 173–81.">going back</a> (at least) to <a href="https://archive.org/details/treatiseofhumann002393mbp/page/124/mode/1up" rel="nofollow noreferrer" title="A Treatise of Human Nature, page. 124, Edited by L.A. Selby-Bigge, 1888, The Clarendon Press">David Hume</a>.
It can be considered as simply a <a href="https://stats.stackexchange.com/q/576031/1562100" title="Probability of seeing sun rise tomorrow using Bayes theorem">Bayesian</a> or <a href="https://math.stackexchange.com/q/1913830/433051" title="Is consecutively-observed evidence stronger in inference?">inferential</a> <a href="https://en.wikipedia.org/wiki/Inductive_reasoning" rel="nofollow noreferrer">induction</a> question,
but as <a href="https://en.wikipedia.org/wiki/Pierre-Simon_Laplace" rel="nofollow noreferrer">Laplace</a> noted in his <a href="https://archive.org/details/philosophicaless00lapliala/page/19/mode/1up" rel="nofollow noreferrer" title="Laplace, A Page 19 of Philosophical Essay on Probabilities. Pierre-Simon (1814).  Translated by Truscott, Frederick Wilson; Emory, Frederick Lincoln. John Wiley &amp; Son and Chapman &amp; Hall.">1814 discussion</a>  of the <a href="https://en.wikipedia.org/wiki/Rule_of_succession" rel="nofollow noreferrer">rule of succession</a>, the odds of the sun rising are:</p>
<blockquote>
<p>… incomparably greater for him who, recognizing in the totality of phenomena the principal regulator of days and seasons, sees that nothing at the present moment can arrest the course of it.</p>
</blockquote>
<p>In other words, if there are no plausible physical &quot;phenomena&quot; that could &quot;arrest the course of it&quot;, simply extrapolating the fact that it has risen every day in the past grossly overestimates the chance that it will not rise tomorrow.  There have been about 1.7 trillion sunrises on <a href="https://en.wikipedia.org/wiki/Age_of_Earth" rel="nofollow noreferrer">4.54 billion year old Earth</a>, so the extrapolated odds for the Sun not rising tomorrow is <span class="math-container">$\sim 10^{-12}$</span>. Correcting for <a href="https://en.wikipedia.org/wiki/Survivorship_bias" rel="nofollow noreferrer">survivorship bias</a> may increase the odds to <span class="math-container">$\sim 10^{-11}$</span> (i.e. a <a href="https://doi.org/10.48550/arXiv.astro-ph/0512204" rel="nofollow noreferrer" title="How unlikely is a doomsday catastrophe?, Max Tegmark and Nick Bostrom, 2005">lower limit of about a billion years</a>  on the Earth's expected lifetime).</p>
<p><strong>Specification</strong></p>
<p>I consider the &quot;Sun not rising tomorrow&quot; to mean one of the following happening with less than a day's warning:</p>
<ul>
<li>The Sun turns off or is destroyed</li>
<li>The Earth stops rotating or is destroyed.</li>
<li>Something blocks the Sun's light from directly reaching any part of the Earth's surface.</li>
</ul>
<p>Mechanisms should not invoke <a href="https://www.youtube.com/watch?v=Z1Ba4BbH0oY" rel="nofollow noreferrer">bureaucratic aliens</a>, <a href="https://biblehub.com/joshua/10-13.htm" rel="nofollow noreferrer">wrathful gods</a>, <a href="https://en.wikipedia.org/wiki/Nuclear_winter" rel="nofollow noreferrer">nuclear winter</a>, <a href="https://en.wikipedia.org/wiki/Death_Star" rel="nofollow noreferrer">Death Stars</a>, <a href="https://en.wikipedia.org/wiki/Supervillain" rel="nofollow noreferrer">comic book supervillains</a>, or magic.
To keep things simple (and relevant to Astronomy SE), please consider only astrophysical mechanisms and ignore possibilities such as a government conspiracy to hide an impending catastrophe from the public, or that <a href="https://doi.org/10.1098/rspa.2020.0658" rel="nofollow noreferrer" title="Probability and consequences of living inside a computer simulation, Alexandre Bibeau-Delisle and Gilles Brassard  , 2021, Proc. R. Soc. A.47720200658">we are all in a computer simulation</a> whose funding has just been cut.</p>
<p><strong>Mechanisms</strong></p>
<p>When talking with students about uncertainty and the sunrise problem, an example mechanism I have used in recent years is that our universe may be in a <a href="https://en.wikipedia.org/wiki/False_vacuum_decay" rel="nofollow noreferrer">metastable false vacuum state</a> that could suddenly decay.  <a href="https://doi.org/10.48550/arXiv.1707.08124" rel="nofollow noreferrer" title="Scale Invariant Instantons and the Complete Lifetime of the Standard Model, Anders Andreassen, William Frost, and Matthew D. Schwartz, Phys. Rev. D 97, 056006 – Published 12 March 2018">One paper</a> estimates that the vacuum decay lifetime of the universe is <span class="math-container">$&gt;10^{65}$</span> years with 95% confidence, which roughly implies that the chance of the Sun not rising tomorrow is <span class="math-container">$\lesssim 10^{-67}$</span>.
I have trouble coming up with more likely possibilities that could sneak up on us without warning:</p>
<ul>
<li>I don't think a <a href="https://en.wikipedia.org/wiki/Supervolcano" rel="nofollow noreferrer">supervolcano</a> could unexpectedly erupt and block the atmosphere with ash <a href="https://earthsky.org/earth/super-eruptions-might-give-a-years-warning/" rel="nofollow noreferrer" title="How much warning for supervolcanoes?">without geophysicists noticing the buildup</a>. (This pretty much leaves only astrophysical catastrophes, which is why I am asking this question on Astronomy SE.)</li>
<li>Wouldn't modern sky surveys give us more than a day's notice of any incoming planet-busting asteroids, comets, or rogue planets, and wouldn't <a href="https://worldbuilding.stackexchange.com/q/225535/98864" title="What would happen if a neutron star approached the solar system?">gravitational perturbations of the solar system</a> reveal approaching rogue neutron stars or stellar-mass black holes? I wonder, however, if a loophole might exist for something like a a 0.0001 solar mass <a href="https://en.wikipedia.org/wiki/Primordial_black_hole" rel="nofollow noreferrer">primordial black hole</a>, but they may not even exist.</li>
<li>A nearby <a href="https://en.wikipedia.org/wiki/Gamma-ray_burst" rel="nofollow noreferrer">Gamma-Ray Burst</a> could perhaps make the Earth's atmosphere opaque by ionizing the Earth's atmosphere or flash boil the oceans into clouds (and would certainly kill all life capable of seeing the Sun rise).  There is an <a href="https://doi.org/10.1038/s41598-017-05796-x" rel="nofollow noreferrer" title="The Resilience of Life to Astrophysical Events. Sloan, D., Alves Batista, R. &amp; Loeb, A. , Sci Rep 7, 5419 (2017)">estimate</a> that the average chance of a Gamma Ray Burst sterilizing an earth-like planet is about <span class="math-container">$3.2\times10^{-19}$</span> per year (i.e. <span class="math-container">$\sim10^{-21}$</span> per day), but I am not sure what the odds are for the Earth itself.</li>
</ul>
<p>To repose the question succinctly: Is there some astrophysical mechanism more likely to stop the Sun from rising tomorrow than the <span class="math-container">$10^{-67}$</span> odds for vacuum decay?</p>
<p><strong>Appendix: Additional Background</strong></p>
<p>This question is already rather long, but more background may be helpful in light of the many comments.</p>
<p>The sunrise problem appears in myriad <a href="https://www.google.com/search?q=%22sunrise+problem%22&amp;source=lnms&amp;tbm=bks" rel="nofollow noreferrer">books</a>, <a href="https://www.google.com/search?q=%22sunrise+problem%22" rel="nofollow noreferrer">websites</a>, and <a href="https://www.google.com/search?q=%22sunrise+problem%22&amp;source=lnms&amp;tbm=vid" rel="nofollow noreferrer">videos</a>.
Aside from Hume and Laplace, it has been discussed by many others, including <a href="https://www.jstor.org/stable/41134121" rel="nofollow noreferrer" title="Buffon, the Certainty of Sunrise, and the Probabilistic Reductio ad Absurdum, Jeff Loveland
Archive for History of Exact Sciences
Vol. 55, No. 5 (April 2001), pp. 465-477">Buffon</a> (of <a href="https://en.wikipedia.org/wiki/Buffon%27s_needle_problem" rel="nofollow noreferrer">Buffon needle</a> fame), <a href="https://en.wikipedia.org/wiki/Richard_Price" rel="nofollow noreferrer">Richard Price</a> in his Appendix to <a href="https://doi.org/10.1098/rstl.1763.0053" rel="nofollow noreferrer" title="Page 409 of An Essay towards Solving a Problem in the Doctrine of Chances. By the Late Rev. Mr. Bayes, F. R. S. Communicated by Mr. Price, in a Letter to John Canton, A. M. F. R. S Philosophical Transactions of the Royal Society of London. 53: 370–418)">Bayes foundational essay</a>, <a href="https://en.wikipedia.org/wiki/John_Maynard_Keynes" rel="nofollow noreferrer">John Maynard Keynes</a> in his <a href="https://archive.org/details/treatiseonprobab007528mbp/page/n257" rel="nofollow noreferrer">&quot;A Treatise on Probability&quot;</a>, and <a href="https://en.wikipedia.org/wiki/Harold_Jeffreys" rel="nofollow noreferrer">Harold Jeffreys</a> in <a href="https://archive.org/details/in.ernet.dli.2015.2608/page/n125" rel="nofollow noreferrer">&quot;Theory Of Probability&quot;</a>.</p>
<p><a href="https://en.wikipedia.org/wiki/Edwin_Thompson_Jaynes" rel="nofollow noreferrer">Jaynes</a> has <a href="https://www.doi.org/10.1017/CBO9780511790423.020" rel="nofollow noreferrer" title="Probability Theory: The Logic of Science, Chapter 18.6 - Laplace’s rule of succession. Edwin Thompson Jaynes. Cambridge University Press. ISBN 978-0-521-59271-0">emphasized</a>, however, that most presentations and criticism ignore Laplace's essential caveat quoted above.</p>
<blockquote>
<p>(Laplace) is pointing out to the reader that the rule of succession gives the probability based only on the information that the event occurred n times in N trials, and that our knowledge of celestial mechanics represents a great deal of additional information. Of course, if you have additional information beyond the numbers n and N , then you ought to take it into account. You are then considering a different problem, the rule of succession no longer applies, and you can reach an entirely different answer.</p>
</blockquote>
<p>So Laplace gave the sunrise problem as an example for his Rule of Succession, and then immediately pointed out that the Rule did not apply because there was so much prior knowledge about the celestial mechanics behind sunrises.  Laplace was emphasizing that a likelihood estimate must use all available prior information.</p>
<p>The statistical part of Laplace's analysis of the sunrise problem has been discussed endlessly but the astronomical caveat has been almost completely ignored.
As far as I am aware, those who do acknowledge the caveat have never quantified the prior, perhaps in part because the typical statistician doesn't have the expertise to assess the astrophysical constraints.
This question is exactly about trying to make a better estimate of this prior.</p>
<p>Versions of this question could plausibly be asked on <a href="https://astronomy.stackexchange.com/">Astronomy</a>, <a href="https://physics.stackexchange.com/">Physics</a>, <a href="https://stats.stackexchange.com/">Cross Validated</a>, <a href="https://worldbuilding.stackexchange.com/">World Building</a>, or even <a href="https://philosophy.stackexchange.com/">Philosophy</a> Stack Exchange sites.
It is possible that answers to the question are more &quot;useful&quot; (or at least engaging) to teachers and students of scientific uncertainty, probability, and statistics, than to astronomers per se, but Astronomy SE seems more likely to have the relevant expertise to estimate the prior.
The most closely relevant research papers are in astrophysics, e.g.  <a href="https://www.nature.com/articles/438754a" rel="nofollow noreferrer" title="
Nature volume 438, page 754 (2005)">&quot;Is a doomsday catastrophe likely?&quot;</a> by <a href="https://en.wikipedia.org/wiki/Max_Tegmark" rel="nofollow noreferrer">Tegmark</a> &amp; <a href="https://en.wikipedia.org/wiki/Nick_Bostrom" rel="nofollow noreferrer">Bostrom</a>
in Nature and <a href="https://doi.org/10.1038/s41598-017-05796-x" rel="nofollow noreferrer" title="Scientific Reports volume 7, Article number: 5419 (2017)">&quot;The Resilience of Life to Astrophysical Events&quot;</a> by Sloan,  Batista, &amp; <a href="https://lweb.cfa.harvard.edu/%7Eloeb/" rel="nofollow noreferrer">Loeb</a> in Nature Scientific Reports.</p>
<p>Even simply listing poorly quantified possible sunrise-stopping mechanisms could be helpful.
It is certainly true that an unknown mechanism might actually be the most likely way that sunrises might stop tomorrow, but bounding the probability from below by listing known processes can still be very useful.</p>

CC BY-SA 4.0
2023-03-27T20:48:33.120Z
I think you struggle to get useful anwers here.  You are in tiny probability land, and weird things happen there.  For example, supervolcano are rare (say one in trillion chance) and you say that the scientists would have noticed -- but perhaps the governments have suppressed this to stop a panic... unlikely, probably not even possible, shall we say a 1-in a million chance.  So put those two together and you have 10^-18,  still much much more likely than your vacuum decay number.   And there are just too many unknowns to make estimations of such tiny probabilities useful.
James K
CC BY-SA 4.0
2023-03-27T20:55:00.283Z
Among the unknowns are the unknowns about us being completely wrong about the sun.  We say it is driven by nuclear fusion in its core.... so it can't "stop working". But perhaps we are completely wrong about that... It's not likely, it is very very unlikely, but I'd bet it is more likely than 10^-67!  And if we are completely wrong about the sun, then how can we possibly answer the question.  This is the problem of getting into tiny probablities.
James K
CC BY-SA 4.0
2023-03-27T20:55:19.443Z
A dark, very high-velocity asteroid might go unnoticed until the very last moment, especially when it comes out of the direction of the sun (100 km/s translates to 8.6 million km/day).
Zac67
CC BY-SA 4.0
2023-03-27T21:59:59.303Z
The only way to estimate probability is to take a sample size and see how many times it occured. Sample size:Every day of recorded history. Times occured:0. So, 0% probability
Starship
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2023-03-27T22:08:26.503Z
I'd bet my bottom dollar that tomorrow there'll be Sun.
notovny
CC BY-SA 4.0
2023-03-27T22:30:45.433Z
I voted this question down for the simple reason that it is not a useful question and the site's purpose is to amass useful questions and answers.  It cannot impart any useful knowledge to attempt to answer it.  Any answer could be disputed and would only be a wild estimate.
StephenG - Help Ukraine
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2023-03-27T23:15:38.373Z
@JamesK I think we will struggle, not the OP. If you had some more experience *asking questions* you'd understand the difference. It's (almost) always the people who don't ask who have the most negative comments on questions.
uhoh
CC BY-SA 4.0
2023-03-27T23:21:28.137Z
@DavidBailey it's a well-written question, +1! This site may be *inadequate* for it, and it might be considered too broad (requiring too many disparate things to be considered to find a single, correct answer) or to be a "list question". If you get too much pushback, consider flagging and asking for moderator assistance to migrate to [Worldbuilding SE](https://worldbuilding.stackexchange.com/)?
uhoh
CC BY-SA 4.0
2023-03-27T23:28:06.020Z
@Starshipisgoforlaunch The correct way to show you do not find a question useful is to vote down.  Voting to close requires choosing a reason and I'm not of the opinion any of the close reasons quite fit my view.  As uhoh points out, it's a well-written question, interesting in a away, but I just regard it as not one that a useful answer can be made for.
StephenG - Help Ukraine
CC BY-SA 4.0
2023-03-28T00:22:54.243Z
If it off-topic, dont upvote it @uhoh
Starship
CC BY-SA 4.0
2023-03-28T00:37:06.223Z
Re: the gamma ray burst. If there was a way to make the Earth's atmosphere opaque, or if every sighted creature on Earth suddenly becomes blind, a la [The Days of the Triffids](https://en.wikipedia.org/wiki/The_Day_of_the_Triffids), or even if life ceased to exist on Earth, just because a sunrise isn't seen or can't be seen doesn't mean a sun rise hasn't, won't or can't occur, it just can't be detected from the surface of the Earth. An entity in outer space observing the Earth will be able to detect if there has an anomaly in the sunrise "system' for Earth, despite on Earth blindness.
Fred
CC BY-SA 4.0
2023-03-28T01:38:51.697Z
Answers - even negative ones - might be more "useful" (or at least engaging) to teachers and students of scientific uncertainty than to astronomers per se, but Astronomy SE seemed more likely than Cross Validated SE to have the relevant expertise.
Similar questions have been considered useful enough to be worked on by some serious scientists and published in well-known journals, e.g. ["Is a doomsday catastrophe likely?"](https://doi.org/10.1038/438754a) in
Nature and
["The Resilience of Life to Astrophysical Events"](https://doi.org/10.1038/s41598-017-05796-x) in Nature Scientific Reports.
David Bailey
CC BY-SA 4.0
2023-03-28T01:39:18.847Z
@Fred Yes, "sunrise" is a ill defined concept, so I would not claim my definition of the "sun not rising" is unique or the best, but I limited my definition to give the question a chance that it might be answerable.
David Bailey
CC BY-SA 4.0
2023-03-28T01:39:41.060Z
Thanks @uhoh. I did briefly think of posting it on Worldbuilding SE, but since I am interested in an answer for the real - not a built - world, I thought Astronomy SE might have more relevant expertise. If there is no interest in answering it here, however, I might follow your suggestion and try migrating it.
David Bailey
CC BY-SA 4.0
2023-03-28T03:30:27.863Z
From https://arxiv.org/abs/0810.5515 "If the probability estimate given by an argument is dwarfed by the chance that the argument itself is flawed, then the estimate is suspect." That link was posted to this question about a low-probability event: https://physics.stackexchange.com/q/606390/123208
PM 2Ring
CC BY-SA 4.0
2023-03-28T06:08:36.977Z
The Carter catastrophe hypothesis would have it that a civilisation-ending event is on the cards quite soon.
ProfRob
CC BY-SA 4.0
2023-03-30T05:45:07.603Z
I suspect that unknown mechanisms are far more probable than any hypothetical mechanism we know about.
ProfRob
CC BY-SA 4.0
2023-03-30T13:00:35.503Z
@ProfRob I certainly agree that unknown mechanisms may be far more probable, but it is still often useful to bound probabilities from below from known mechanisms. For example, during the era when searching for proton decay was a big thing, I thought it interesting that gravitational interactions probably mean the proton lifetime is $>10^{45}$ years, even though we hoped that the actual lifetime was much, much shorter. Knowing about the neutrino floor is useful for direct Dark Matter searches.
David Bailey
<earth><rogue-planet><sunrise><gamma-ray-bursts><impact-probability>
What is the chance that the Sun will not rise tomorrow?
David Bailey
# What is the chance that the Sun will not rise tomorrow?

(Asked by: username_0 on 2023-03-27)

What is the most likely natural astrophysical mechanism for the "Sun not rising tomorrow", consistent with our scientific knowledge today?

**Background**

The "[sunrise problem](https://en.wikipedia.org/wiki/Sunrise_problem) - *What is the probability that the Sun will rise tomorrow?* -
is a classic probabilistic conundrum [going back](https://www.jstor.org/stable/41133850 "Buffon, Price, and Laplace: Scientific Attribution in the 18th Century. S. L. Zabell, Archive for History of Exact Sciences, vol. 39, no. 2, 1988, pp. 173–81.") (at least) to [David Hume](https://archive.org/details/treatiseofhumann002393mbp/page/124/mode/1up "A Treatise of Human Nature, page. 124, Edited by L.A. Selby-Bigge, 1888, The Clarendon Press").
It can be considered as simply a [Bayesian](https://stats.stackexchange.com/q/576031/1562100 "Probability of seeing sun rise tomorrow using Bayes theorem") or [inferential](https://math.stackexchange.com/q/1913830/433051 "Is consecutively-observed evidence stronger in inference?") [induction](https://en.wikipedia.org/wiki/Inductive_reasoning) question,
but as [Laplace](https://en.wikipedia.org/wiki/Pierre-Simon_Laplace) noted in his [1814 discussion](https://archive.org/details/philosophicaless00lapliala/page/19/mode/1up "Laplace, A Page 19 of Philosophical Essay on Probabilities. Pierre-Simon (1814).  Translated by Truscott, Frederick Wilson; Emory, Frederick Lincoln. John Wiley & Son and Chapman & Hall.") of the [rule of succession](https://en.wikipedia.org/wiki/Rule_of_succession), the odds of the sun rising are:

> … incomparably greater for him who, recognizing in the totality of phenomena the principal regulator of days and seasons, sees that nothing at the present moment can arrest the course of it.

In other words, if there are no plausible physical "phenomena" that could "arrest the course of it", simply extrapolating the fact that it has risen every day in the past grossly overestimates the chance that it will not rise tomorrow. There have been about 1.7 trillion sunrises on [4.54 billion year old Earth](https://en.wikipedia.org/wiki/Age_of_Earth), so the extrapolated odds for the Sun not rising tomorrow is $\sim 10^{-12}$. Correcting for [survivorship bias](https://en.wikipedia.org/wiki/Survivorship_bias) may increase the odds to $\sim 10^{-11}$ (i.e. a [lower limit of about a billion years](https://doi.org/10.48550/arXiv.astro-ph/0512204 "How unlikely is a doomsday catastrophe?, Max Tegmark and Nick Bostrom, 2005") on the Earth's expected lifetime).

**Specification**

I consider the "Sun not rising tomorrow" to mean one of the following happening with less than a day's warning:

* The Sun turns off or is destroyed
* The Earth stops rotating or is destroyed.
* Something blocks the Sun's light from directly reaching any part of the Earth's surface.

Mechanisms should not invoke [bureaucratic aliens](https://www.youtube.com/watch?v=Z1Ba4BbH0oY), [wrathful gods](https://biblehub.com/joshua/10-13.htm), [nuclear winter](https://en.wikipedia.org/wiki/Nuclear_winter), [Death Stars](https://en.wikipedia.org/wiki/Death_Star), [comic book supervillains](https://en.wikipedia.org/wiki/Supervillain), or magic.
To keep things simple (and relevant to Astronomy SE), please consider only astrophysical mechanisms and ignore possibilities such as a government conspiracy to hide an impending catastrophe from the public, or that [we are all in a computer simulation](https://doi.org/10.1098/rspa.2020.0658 "Probability and consequences of living inside a computer simulation, Alexandre Bibeau-Delisle and Gilles Brassard  , 2021, Proc. R. Soc. A.47720200658") whose funding has just been cut.

**Mechanisms**

When talking with students about uncertainty and the sunrise problem, an example mechanism I have used in recent years is that our universe may be in a [metastable false vacuum state](https://en.wikipedia.org/wiki/False_vacuum_decay) that could suddenly decay. [One paper](https://doi.org/10.48550/arXiv.1707.08124 "Scale Invariant Instantons and the Complete Lifetime of the Standard Model, Anders Andreassen, William Frost, and Matthew D. Schwartz, Phys. Rev. D 97, 056006 – Published 12 March 2018") estimates that the vacuum decay lifetime of the universe is $>10^{65}$ years with 95% confidence, which roughly implies that the chance of the Sun not rising tomorrow is $\lesssim 10^{-67}$.
I have trouble coming up with more likely possibilities that could sneak up on us without warning:

* I don't think a [supervolcano](https://en.wikipedia.org/wiki/Supervolcano) could unexpectedly erupt and block the atmosphere with ash [without geophysicists noticing the buildup](https://earthsky.org/earth/super-eruptions-might-give-a-years-warning/ "How much warning for supervolcanoes?"). (This pretty much leaves only astrophysical catastrophes, which is why I am asking this question on Astronomy SE.)
* Wouldn't modern sky surveys give us more than a day's notice of any incoming planet-busting asteroids, comets, or rogue planets, and wouldn't [gravitational perturbations of the solar system](https://worldbuilding.stackexchange.com/q/225535/98864 "What would happen if a neutron star approached the solar system?") reveal approaching rogue neutron stars or stellar-mass black holes? I wonder, however, if a loophole might exist for something like a a 0.0001 solar mass [primordial black hole](https://en.wikipedia.org/wiki/Primordial_black_hole), but they may not even exist.
* A nearby [Gamma-Ray Burst](https://en.wikipedia.org/wiki/Gamma-ray_burst) could perhaps make the Earth's atmosphere opaque by ionizing the Earth's atmosphere or flash boil the oceans into clouds (and would certainly kill all life capable of seeing the Sun rise). There is an [estimate](https://doi.org/10.1038/s41598-017-05796-x "The Resilience of Life to Astrophysical Events. Sloan, D., Alves Batista, R. & Loeb, A. , Sci Rep 7, 5419 (2017)") that the average chance of a Gamma Ray Burst sterilizing an earth-like planet is about $3.2\times10^{-19}$ per year (i.e. $\sim10^{-21}$ per day), but I am not sure what the odds are for the Earth itself.

To repose the question succinctly: Is there some astrophysical mechanism more likely to stop the Sun from rising tomorrow than the $10^{-67}$ odds for vacuum decay?

**Appendix: Additional Background**

This question is already rather long, but more background may be helpful in light of the many comments.

The sunrise problem appears in myriad [books](https://www.google.com/search?q=%22sunrise+problem%22&source=lnms&tbm=bks), [websites](https://www.google.com/search?q=%22sunrise+problem%22), and [videos](https://www.google.com/search?q=%22sunrise+problem%22&source=lnms&tbm=vid).
Aside from Hume and Laplace, it has been discussed by many others, including [Buffon](https://www.jstor.org/stable/41134121 "Buffon, the Certainty of Sunrise, and the Probabilistic Reductio ad Absurdum, Jeff Loveland
Archive for History of Exact Sciences
Vol. 55, No. 5 (April 2001), pp. 465-477") (of [Buffon needle](https://en.wikipedia.org/wiki/Buffon%27s_needle_problem) fame), [Richard Price](https://en.wikipedia.org/wiki/Richard_Price) in his Appendix to [Bayes foundational essay](https://doi.org/10.1098/rstl.1763.0053 "Page 409 of An Essay towards Solving a Problem in the Doctrine of Chances. By the Late Rev. Mr. Bayes, F. R. S. Communicated by Mr. Price, in a Letter to John Canton, A. M. F. R. S Philosophical Transactions of the Royal Society of London. 53: 370–418)"), [John Maynard Keynes](https://en.wikipedia.org/wiki/John_Maynard_Keynes) in his ["A Treatise on Probability"](https://archive.org/details/treatiseonprobab007528mbp/page/n257), and [Harold Jeffreys](https://en.wikipedia.org/wiki/Harold_Jeffreys) in ["Theory Of Probability"](https://archive.org/details/in.ernet.dli.2015.2608/page/n125).

[Jaynes](https://en.wikipedia.org/wiki/Edwin_Thompson_Jaynes) has [emphasized](https://www.doi.org/10.1017/CBO9780511790423.020 "Probability Theory: The Logic of Science, Chapter 18.6 - Laplace’s rule of succession. Edwin Thompson Jaynes. Cambridge University Press. ISBN 978-0-521-59271-0"), however, that most presentations and criticism ignore Laplace's essential caveat quoted above.

> (Laplace) is pointing out to the reader that the rule of succession gives the probability based only on the information that the event occurred n times in N trials, and that our knowledge of celestial mechanics represents a great deal of additional information. Of course, if you have additional information beyond the numbers n and N , then you ought to take it into account. You are then considering a different problem, the rule of succession no longer applies, and you can reach an entirely different answer.

So Laplace gave the sunrise problem as an example for his Rule of Succession, and then immediately pointed out that the Rule did not apply because there was so much prior knowledge about the celestial mechanics behind sunrises. Laplace was emphasizing that a likelihood estimate must use all available prior information.

The statistical part of Laplace's analysis of the sunrise problem has been discussed endlessly but the astronomical caveat has been almost completely ignored.
As far as I am aware, those who do acknowledge the caveat have never quantified the prior, perhaps in part because the typical statistician doesn't have the expertise to assess the astrophysical constraints.
This question is exactly about trying to make a better estimate of this prior.

Versions of this question could plausibly be asked on [Astronomy](https://astronomy.stackexchange.com/), [Physics](https://physics.stackexchange.com/), [Cross Validated](https://stats.stackexchange.com/), [World Building](https://worldbuilding.stackexchange.com/), or even [Philosophy](https://philosophy.stackexchange.com/) Stack Exchange sites.
It is possible that answers to the question are more "useful" (or at least engaging) to teachers and students of scientific uncertainty, probability, and statistics, than to astronomers per se, but Astronomy SE seems more likely to have the relevant expertise to estimate the prior.
The most closely relevant research papers are in astrophysics, e.g. ["Is a doomsday catastrophe likely?"](https://www.nature.com/articles/438754a "
Nature volume 438, page 754 (2005)") by [Tegmark](https://en.wikipedia.org/wiki/Max_Tegmark) & [Bostrom](https://en.wikipedia.org/wiki/Nick_Bostrom)
in Nature and ["The Resilience of Life to Astrophysical Events"](https://doi.org/10.1038/s41598-017-05796-x "Scientific Reports volume 7, Article number: 5419 (2017)") by Sloan, Batista, & [Loeb](https://lweb.cfa.harvard.edu/%7Eloeb/) in Nature Scientific Reports.

Even simply listing poorly quantified possible sunrise-stopping mechanisms could be helpful.
It is certainly true that an unknown mechanism might actually be the most likely way that sunrises might stop tomorrow, but bounding the probability from below by listing known processes can still be very useful.

**Tags:** earth, rogue-planet, sunrise, gamma-ray-bursts, impact-probability
> **Comments:**
> **username_1**: I think you struggle to get useful anwers here.  You are in tiny probability land, and weird things happen there.  For example, supervolcano are rare (say one in trillion chance) and you say that the scientists would have noticed -- but perhaps the governments have suppressed this to stop a panic... unlikely, probably not even possible, shall we say a 1-in a million chance.  So put those two together and you have 10^-18,  still much much more likely than your vacuum decay number.   And there are just too many unknowns to make estimations of such tiny probabilities useful.  
> **username_1**: Among the unknowns are the unknowns about us being completely wrong about the sun.  We say it is driven by nuclear fusion in its core.... so it can't "stop working". But perhaps we are completely wrong about that... It's not likely, it is very very unlikely, but I'd bet it is more likely than 10^-67!  And if we are completely wrong about the sun, then how can we possibly answer the question.  This is the problem of getting into tiny probablities.  
> **username_2**: A dark, very high-velocity asteroid might go unnoticed until the very last moment, especially when it comes out of the direction of the sun (100 km/s translates to 8.6 million km/day).  
> **username_3**: The only way to estimate probability is to take a sample size and see how many times it occured. Sample size:Every day of recorded history. Times occured:0. So, 0% probability  
> **username_4**: I'd bet my bottom dollar that tomorrow there'll be Sun.  
> **username_5**: I voted this question down for the simple reason that it is not a useful question and the site's purpose is to amass useful questions and answers.  It cannot impart any useful knowledge to attempt to answer it.  Any answer could be disputed and would only be a wild estimate.  
> **username_6**: @JamesK I think we will struggle, not the OP. If you had some more experience *asking questions* you'd understand the difference. It's (almost) always the people who don't ask who have the most negative comments on questions.  
> **username_6**: @DavidBailey it's a well-written question, +1! This site may be *inadequate* for it, and it might be considered too broad (requiring too many disparate things to be considered to find a single, correct answer) or to be a "list question". If you get too much pushback, consider flagging and asking for moderator assistance to migrate to [Worldbuilding SE](https://worldbuilding.stackexchange.com/)?  
> **username_5**: @Starshipisgoforlaunch The correct way to show you do not find a question useful is to vote down.  Voting to close requires choosing a reason and I'm not of the opinion any of the close reasons quite fit my view.  As uhoh points out, it's a well-written question, interesting in a away, but I just regard it as not one that a useful answer can be made for.  
> **username_3**: If it off-topic, dont upvote it @uhoh  
> **username_7**: Re: the gamma ray burst. If there was a way to make the Earth's atmosphere opaque, or if every sighted creature on Earth suddenly becomes blind, a la [The Days of the Triffids](https://en.wikipedia.org/wiki/The_Day_of_the_Triffids), or even if life ceased to exist on Earth, just because a sunrise isn't seen or can't be seen doesn't mean a sun rise hasn't, won't or can't occur, it just can't be detected from the surface of the Earth. An entity in outer space observing the Earth will be able to detect if there has an anomaly in the sunrise "system' for Earth, despite on Earth blindness.  
> **username_0**: Answers - even negative ones - might be more "useful" (or at least engaging) to teachers and students of scientific uncertainty than to astronomers per se, but Astronomy SE seemed more likely than Cross Validated SE to have the relevant expertise. Similar questions have been considered useful enough to be worked on by some serious scientists and published in well-known journals, e.g. ["Is a doomsday catastrophe likely?"](https://doi.org/10.1038/438754a) in Nature and ["The Resilience of Life to Astrophysical Events"](https://doi.org/10.1038/s41598-017-05796-x) in Nature Scientific Reports.  
> **username_0**: @Fred Yes, "sunrise" is a ill defined concept, so I would not claim my definition of the "sun not rising" is unique or the best, but I limited my definition to give the question a chance that it might be answerable.  
> **username_0**: Thanks @uhoh. I did briefly think of posting it on Worldbuilding SE, but since I am interested in an answer for the real - not a built - world, I thought Astronomy SE might have more relevant expertise. If there is no interest in answering it here, however, I might follow your suggestion and try migrating it.  
> **username_8**: From https://arxiv.org/abs/0810.5515 "If the probability estimate given by an argument is dwarfed by the chance that the argument itself is flawed, then the estimate is suspect." That link was posted to this question about a low-probability event: https://physics.stackexchange.com/q/606390/123208  
> **username_9**: The Carter catastrophe hypothesis would have it that a civilisation-ending event is on the cards quite soon.  
> **username_9**: I suspect that unknown mechanisms are far more probable than any hypothetical mechanism we know about.  
> **username_0**: @ProfRob I certainly agree that unknown mechanisms may be far more probable, but it is still often useful to bound probabilities from below from known mechanisms. For example, during the era when searching for proton decay was a big thing, I thought it interesting that gravitational interactions probably mean the proton lifetime is $>10^{45}$ years, even though we hoped that the actual lifetime was much, much shorter. Knowing about the neutrino floor is useful for direct Dark Matter searches.  

---

## 2 answers

### Answer by username_10 on 2023-04-03. Score: 3

My guess is that the most likely mechanism would be something like a world-war/pandemic that temporarily prevents astronomers from analyzing sky surveys and/or prevents planetary defense strategies AND a large asteroid/rogue planet that could destroy the Earth. Obviously both of these are extremely low-probability but I suspect that even their intersection would be the most likely mechanism.

And here's some poor quantification for you:

Suppose some of these disastrous wars/pandemics were: COVID-19, Spanish Flu, Black Plague, World War 1, and World War 2. They average around 3 years each, so during human history, about $(3 \text{ yrs/disaster}) \* (5 \text{ disasters}) = 15 \text{ yrs}$ have been spent in extreme disaster. I know these numbers are very rough estimates but for a question like this, you can't expect much precision. I'll also suppose human history started around 200 000 years ago. Then,

$$P(\text{war/pandemic})\approxeq 15/200000 \approxeq 7.5 \times 10^{-5}$$

Furthermore, let's suppose the only giant-impact in Earth's history was the moon formation event. Also, if the Earth is 4.5 billion years old, it is $(365)(4.5 \times 10^9) \approxeq 1.6 \times 10^{12}$ days old. Then,

$$P(\text{earth destruction}) \approxeq 1/1.6 \times 10^{12} \approxeq 6.1 \times 10^{-13}$$

Therefore, $$P(\text{war/pandemic} \cap \text{earth destruction}) \approxeq (7.5 \times 10^{-5})(6.1 \times 10^{-13}) = 4.6 \times 10^{-17}$$

> **Comments:**
> **username_0**: Thanks Thomas.  I was initially thinking in answers for "tomorrow", where "today" is March/April 2023, but I certainly agree that averaging "today" over the near future (e.g. the next 100 years) where disasters may happen, as you have effectively done, is also a reasonable approach and very interesting.  Given the huge uncertainties, I am very happy with very rough order-of-magnitude estimates.  
> **username_7**: I tend to agree with overall concept of this answer, but the probabilities need more work.  It could be argued that two **world** wars, & very destructive ones at that, & pandemics are features of only the 20th Century. The Black Death Plagues, affected large areas over significant time periods, but they weren't global pandemics during a particular era. Also, pandemics rely on large numbers of people moving global with ease & speed over short time spans.  Applying any statistics specific to the 20th Century for the period that homo sapiens have been extant is incorrect. ...  
> **username_7**: Moon forming, nearly Earth destroying events, OK, but what about Chicxulub meteor type events (the so called dinosaur killer), or even smaller ones wiping out a locality?  
> **username_10**: @Fred the meteor would have to "destroy the Earth" as per the specifications provided in the question so it excludes events where localities are wiped out. I agree that it's inaccurate to apply recent world-wide catastrophes to the entire duration of human history but then again, planetary defense systems have only existed for about 10 years, so there's really not a large enough sample size to estimate a probability with much accuracy anyways. I was erring on the safe side and trying to underestimate the probabilities.  

---

### Answer by username_0 on 2023-04-06. Score: 1

I have thought a bit more about possible mechanisms that might "stop the sunrise", so I am posting my own incomplete answer in case anyone might find it pedagogically useful.

**Supervolcano**

I confirmed onthat an unexpected supervolcano eruption could not block the sun by tomorrow. Although there is [no single model for supervolcanoes](https://doi.org/10.1038/s43017-021-00191-7 "No single model for supersized eruptions and their magma bodies., Wilson, C.J.N., Cooper, G.F., Chamberlain, K.J. et al.  Nat Rev Earth Environ 2, 610–627 (2021)"), the time taken for magma to gather is far longer than a day. Also, even if a single supervolcano could unexpectedly erupt, it would take more than a day for its ash to cloud the entire Earth. For example, after the [Chernobyl disaster](https://en.wikipedia.org/wiki/Chernobyl_disaster), it [took almost two weeks](https://doi.org/10.1016/0265-931X(88)90055-0 "On the transport of Chernobyl radioactivity to eastern Canada, J.-C. Roy, J.-E. Côté, A. Mahfoud, S. Villeneuve, J. Turcotte, Journal of Environmental Radioactivity, Volume 6, Issue 2,1988, Pages 121-130") for the radioactive cloud to reach eastern Canada.

**Asteroid Impact**

Unlike a supervolcano, a single asteroid impact could cloud the entire Earth's atmosphere within a day because hot ejecta rains down over the entire planet, setting fires and vaporizing water. It is [estimated](https://doi.org/10.5194/acp-16-13185-2016 "Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact, Toon, O. B., Bardeen, C., and Garcia, R.:, Atmos. Chem. Phys., 16, 13185–13212, 2016.") that the gases and ejecta from the 10 km [Chicxulub impactor](https://en.wikipedia.org/wiki/Chicxulub_crater) covered the globe within hours. It might take a few days for a 1 km impactor.
Taking human crises into account, @Thomas's very rough [order-of-magnitude estimate](https://astronomy.stackexchange.com/a/53305/47727) of $\sim 10^{-17}$/day risk averaged over the the near future seems reasonable. Since a Chicxulub impact is sufficient, however, I think the appropriate impactor time scale is closer to 100 million years than Thomas's 4.5 billion years, giving $\sim 10^{-15}$/day risk. Pretty much all answers for this question must be [Fermi estimates](https://en.wikipedia.org/wiki/Fermi_problem), so a factor of two uncertainty difference in the exponent is not really significant. The answers to ["How early could we detect an asteroid the size of the one that caused the extinction of the dinosaurs?"](https://astronomy.stackexchange.com/q/39837/47727) illustrate some of the challenges in estimating how much warning we might have.

Failures due to human crises aside, there might be some impactors that would be tough to detect, but I haven't been able yet to make a quantitative odds estimate:

* Interstellar objects might be missed even if current detection networks are working well. [ʻOumuamua](https://en.wikipedia.org/wiki/%CA%BBOumuamua) was [only detected](https://astronomy.com/magazine/2020/02/our-first-interstellar-visitor) a week after its closest approach to Earth, but it was likely too small to be a sunrise stopping impactor.
* A group of smaller co-travelling objects (perhaps produced in an earlier asteroid-asteroid collision?) might be harder to detect and require less total mass to cloud the Earth if the impacts were spread over the globe. This would be similar to [Comet Shoemaker-Levy](https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9#Impacts) that was a 21 piece "freight train" that hit Jupiter over several days.

**Primordial Black Holes**

If [primordial black holes](https://en.wikipedia.org/wiki/Primordial_black_hole) exist, the probability of one colliding with the Earth is [estimated by Rahvar](https://doi.org/10.1093/mnras/stab2239 "Possibility of primordial black holes collision with Earth and the consequences of this collision, Sohrab Rahvar, MNRAS 507, 914–918 (2021)") to be
$$\frac{dN}{dt} \approx 10^{-8}f\left(\frac{M}{10^{23}\mathrm{gr}}\right)^{-1}\mathrm{Gyr}^{-1}
\sim10^{-30}f\left(\frac{M\_\odot}{M}\right)\mathrm{day}^{-1}$$

where $f$ is the fraction of dark matter made of mass $M$ primordial black holes, and $M\_\odot$ is the Sun's mass.
For the $0.0001 M\_\odot$ mass primordial black hole mentioned in the question, [Carr et al estimate](https://doi.org/10.48550/arXiv.2002.12778 "Constraints on primordial black holes,Bernard Carr et al 2021 Rep. Prog. Phys. 84 116902") and upper bound of $f\lesssim 10^{-2}$, giving
$\frac{dN}{dt} \lesssim 10^{-28}\mathrm{day}^{-1}$, considerably less than the asteroid impact probability above.

**Sun going dark**

Although this question is primarily about *mechanisms* that could unexpectedly destroy the Sun or the Earth or block the sunlight, it is interesting that there is a current ongoing research project that simply looks for stars that disappear.
The [VASCO project](https://vascoproject.org/ "Vanishing & Appearing Sources during a Century of Observations") has recently searched for [vanishing stars](https://vascoproject.org/vanishing-stars/) and other astrophysical objects that may have disappeared. Based on [5399 sources](https://doi.org/10.1093/mnras/stac1552 "Discovering vanishing objects in POSS I red images using the Virtual Observatory, Enrique Solano, B. Villarroe and C. Rodrigo, MNRAS 515, 1380–1391 (2022)") that disappeared over $\sim$70 years out of [600 million objects](https://doi.org/10.3847/1538-3881/ab570f "The Vanishing and Appearing Sources during a Century of Observations Project. I. USNO Objects Missing in Modern Sky Surveys and Follow-up Observations of a Missing Star, Beatriz Villarroel et al., The Astronomical Journal, 159:8 (19pp), 2020 January")
from the United States Naval Observatory (USNO) B1 catalog, the naive disappearance rate is $4\times 10^{-10}$/day.
This is much higher than the undetected asteroid impact rate above, but it isn't a very helpful number since most (and perhaps all) of these disappearances are for sources unlike the Sun, and we expect that most (and likely all) are due to known processes e.g. [failed supernova](https://en.wikipedia.org/wiki/Failed_supernova) or observation artifacts. [Some of the disappearances](https://doi.org/10.1038/s41598-021-92162-7 "Exploring nine simultaneously occurring transients on April 12th 1950, Villarroel, B., Marcy, G.W., Geier, S. et al. Sci Rep 11, 12794 (2021)") and the [sheer number](https://www.youtube.com/watch?v=X3xddkS4H80 "Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?, Anton Petrov, YouTube, 24 Sep 2021") seem hard to explain, but the data are not yet well enough understood to set limits on specific classes of stars.


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