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Archive for Science & Space

 

Astronomers to peer into a black hole for first time with new Event Horizon Telescope

April 3, 2017 Alan Science & Space No comments On April 5-14 2017, the team behind the Event Horizon Telescope hopes to test the fundamental theories of black-hole physics by attempting to take the first ever image of a black hole’s event horizon (the point at which theory predicts nothing can escape). By connecting a global array of radio telescopes together to form the equivalent of a giant Earth-sized telescope – using a technique known as Very Long Baseline Interferometry and Earth-aperture synthesis – scientists will peer into the heart of our Milky Way galaxy where a black hole that is 4m times more massive than our sun – Sagittarius A* – lurks.

Source: Astronomers to peer into a black hole for first time with new Event Horizon Telescope 

Study reveals substantial evidence of holographic universe

February 5, 2017 Alan Science & Space No comments 

Source: Study reveals substantial evidence of holographic universe

We just got the first real evidence of a strange quantum distortion in empty space

December 4, 2016 Alan Science & Space No comments For the first time, astronomers have observed a strange quantum phenomenon in action, where a neutron star is surrounded by a magnetic field so intense, it’s given rise to a region in empty space where matter spontaneously pops in and out of existence.

Called vacuum birefringence, this bizarre phenomenon was first predicted back in the 1930s, but had only ever been observed on the atomic scale. Now scientists have finally seen it occur in nature, and it goes against everything that Newton and Einstein had mapped out.

“This is a macroscopic manifestation of quantum field,” Jeremy Heyl from the University of British Columbia in Canada, who was not involved in the research, told Science. “It’s manifest on the scale of a neutron star.”

An international team of astronomers led by Roberto Mignani from INAF Milan in Italy made the discovery while observing a neutron star called RX J1856.5-3754 that’s 400 light-years from Earth.

Neutron stars are the crushed cores of massive stars that collapsed under their own weight when they ran out of fuel, and exploded as a supernova.

They’re made of some of the most dense material in the Universe – just 1 teaspoon of the stuff would weigh 1 billion tons on Earth – and their crust is 10 billion times stronger than steel.

Neutron stars also have the strongest magnetic fields in the known Universe – astronomers predict that the strongest neutron star magnetic fields are nearly 100 trillion times stronger than Earth’s.

These magnetic fields are so ridiculous, they’re thought to affect the properties of the empty space surrounding a neutron star.

According to quantum electrodynamics (QED) – a quantum theory that describes how light and matter interact – it’s predicted that space is actually full of ‘virtual particles’ that pop in and out of existence and mess with the activity of light particles (photons) as they zip around the Universe.

These virtual particles aren’t like regular physical particles like electrons and photons, but are fluctuations in quantum fields that have similar properties to a regular particle – the big difference being that they can appear and vanish at any point in space and time.

In regular empty space, photons aren’t affected by these virtual particles, and travel without interference.

But in the empty space near the incredibly intense magnetic field of a neutron star, these virtual particles are ‘excited’, and they have a dramatic effect on any photons passing through.

“According to QED, a highly magnetised vacuum behaves as a prism for the propagation of light, an effect known as vacuum birefringence,” Mignani explains in a press release.

“This effect can be detected only in the presence of enormously strong magnetic fields, such as those around neutron stars,” adds team member Roberto Turolla from the University of Padua in Italy.

As Jay Bennett reports for Popular Mechanics, the researchers directed the world’s most advanced ground-based telescope, the European Southern Observatory’s Very Large Telescope (VLT), at their neutron star, and observed linear polarisation – the alignment of light waves influenced by electromagnetic forced – in the empty space around the star.

“This is rather odd, because conventional relativity says that light should pass freely through a vacuum, such as space, without being altered,” says Bennett.

“The linear polarisation was to such a degree (16 degrees, to be precise) that the only known explanations are theories of QED and the influence of virtual particles.”

You can see an illustration of this at the top of the page, where light coming from the surface of a neutron star (on the left) becomes linearly polarised as it travels through the vacuum of space on its way to the observer on Earth (on the right).

The next step now is for the observations to be replicated in another scenario to know for sure that vacuum birefringence is what we’re looking at here, and if that’s the case, we’ve got a whole new phenomenon to investigate in the field of quantum mechanics.

“When Einstein came up with the theory of general relativity 100 years ago, he had no idea that it would be used for navigational systems. The consequences of this discovery probably will also have to be realised on a longer timescale,” Magnani told New Scientist.

The research has been published in Monthly Notices of the Royal Astronomical Society, and you can access it for free at arXiv.org.

Source: We just got the first real evidence of a strange quantum distortion in empty space – ScienceAlert

It’s official: NASA’s peer-reviewed EM Drive paper has finally been published

November 21, 2016 Alan Science & Space No comments After months of speculation and leaked documents, NASA’s long-awaited EM Drive paper has finally been peer-reviewed and published. And it shows that the ‘impossible’ propulsion system really does appear to work.

The NASA Eagleworks Laboratory team even put forward a hypothesis for how the EM Drive could produce thrust – something that seems impossible according to our current understanding of the laws of physics.

And now we finally have those results.

The new peer-reviewed paper is titled “Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum“, and has been published online as an open access ‘article in advance’ in the American Institute of Aeronautics and Astronautics (AIAA)’s Journal of Propulsion and Power. It’ll appear in the December print edition.


The scientific community is also notoriously unconvinced about the propulsion system – just yesterday a Motherboard article on the EM Drive was deleted by the moderators of the popular subreddit r/Physics because they “consider the EM Drive to be unscientific”.

But is the first peer-reviewed research ever published on the EM Drive, which firmly takes it out of the realm of pseudoscience into a technology that’s worth taking skeptically, but seriously.

The next step for the EM Drive is for it to be tested in space, which is scheduled to happen in the coming months, with plans to launch the first EM Drive having been made back in September.

read full article: http://www.sciencealert.com/it-s-official-nasa-s-peer-reviewed-em-drive-paper-has-finally-been-published 

Hubble detects giant ‘cannonballs’ shooting from star

October 6, 2016 Alan Science & Space No comments 

Read more at: http://phys.org/news/2016-10-hubble-giant-cannonballs-star.html#jCp

Source: Hubble detects giant ‘cannonballs’ shooting from star

Time crystals might exist after all

September 11, 2016 Alan Science & Space No comments Although spontaneously broken time-translation symmetry has never been observed before, almost every other type of spontaneous symmetry breaking has been. One very common example of a spontaneously broken symmetry occurs in magnets. The laws of nature do not impose which side of a magnet will be the north pole and which will be the south pole. The distinguishing feature of any magnetic material, however, is that it spontaneously breaks this symmetry and chooses one side to be the north pole. Another example is ordinary crystals. Although the laws of nature are invariant under rotating or shifting (translating) space, crystals spontaneously break these spatial symmetries because they look different when viewed from different angles and when shifted a little bit in space.

In their new study, the physicists specifically define what it would take to spontaneously break time-translation symmetry, and then use simulations to predict that this broken symmetry should occur in a large class of quantum systems called “Floquet-many-body-localized driven systems.” The scientists explain that the key aspect of these systems is that they remain far from thermal equilibrium at all times, so the system never heats up.

The new definition of broken time-translation symmetry is similar to the definitions of other broken symmetries. Basically, when the size of a system (such as a crystal) grows, the time taken for a symmetry-breaking state to decay into a symmetry-respecting state increases, and in an infinite system the symmetry-respecting state can never be reached. As a result, symmetry for the entire system is broken.

“The significance of our work is two-fold: on one hand, it demonstrates that time-translation symmetry is not immune to being spontaneously broken,” said coauthor Bela Bauer, a researcher at Microsoft Station Q. “On the other hand, it deepens our understanding that non-equilibrium systems can host many interesting states of matter that cannot exist in equilibrium systems.”

According to the physicists, it should be possible to perform an experiment to observe time-translation symmetry breaking by using a large system of trapped atoms, trapped ions, or superconducting qubits to fabricate a time crystal, and then measure how these systems evolve over time. The scientists predict that the systems will exhibit the periodic, oscillating motion that is characteristic of time crystals and indicative of spontaneously broken time-translation symmetry.

Source: Time crystals might exist after all

Also: sciencealert.com

The wizard war in orbit: Early American signals intelligence satellites 

Is the black hole at our galaxy’s centre a quantum computer?

April 9, 2016 Alan Science & Space No comments

After you die, your body’s atoms will disperse and find new venues, making their way into oceans, trees and other bodies. But according to the laws of quantum mechanics, all of the information about your body’s build and function will prevail. The relations between the atoms, the uncountable particulars that made you you, will remain forever preserved, albeit in unrecognisably scrambled form – lost in practice, but immortal in principle.

There is only one apparent exception to this reassuring concept: according to our current physical understanding, information cannot survive an encounter with a black hole. Forty years ago, Stephen Hawking demonstrated that black holes destroy information for good. Whatever falls into a black hole disappears from the rest of the Universe. It eventually reemerges in a wind of particles – ‘Hawking radiation’ – that leaks away from the event horizon, the black hole’s outer physical boundary. In this way, black holes slowly evaporate, but the process erases all knowledge about the black hole’s formation. The radiation merely carries data for the total mass, charge and angular momentum of the matter that collapsed; every other detail about anything that fell into the black hole is irretrievably lost.

Hawking’s discovery of black-hole evaporation has presented theoretical physicists with a huge conundrum: general relativity says that black holes must destroy information; quantum mechanics says it cannot happen because information must live on eternally. Both general relativity and quantum mechanics are extremely well-tested theories, and yet they refuse to combine. The clash reveals something much more fundamental than a seemingly exotic quirk about black holes: the information paradox makes it aptly clear that physicists still do not understand the fundamental laws of nature.

But Gia Dvali, professor of physics at the Ludwig-Maximilians University of Munich, believes he’s found the solution. ‘Black holes are quantum computers,’ he says. ‘We have an explicit information-processing sequence.’ If he is correct, the paradox is no more, and information truly is immortal. Even more startling, perhaps, is that his concept has practical implications. In the future, we might be able to tap black-hole physics to construct quantum computers of our own.

Read full article: Is the black hole at our galaxy’s centre a quantum computer? | Aeon Essays

Einstein’s gravitational waves ‘seen’ from black holes

February 11, 2016 Alan Science & Space No comments 

The research, by the LIGO Collaboration, has been published today in the journal Physical Review Letters.

Gravitational waves: A triumph for big science

The merger radiated three times the mass of the sun in pure gravitational energy.

“We have detected gravitational waves,” Prof David Reitze, executive director of the LIGO project, told journalists at a news conference in Washington DC.

“It’s the first time the Universe has spoken to us through gravitational waves. Up until now, we’ve been deaf.”

Source: Einstein’s gravitational waves ‘seen’ from black holes – BBC News

The bizarre reactor that might save nuclear fusion

October 23, 2015 Alan Science & Space No comments Read more: The bizarre reactor that might save nuclear fusion | Science/AAAS | News
