Ask Ethan #103: Have We Solved The Black Hole Information Paradox?

A wormhole, or Einstein-Rosen Bridge, is a hypothetical topological feature that would fundamentally be a shortcut connecting two separate points in spacetime that could connect extremely far distances such as a billion light years or more, short distances, such as a few feet, different universes, and in theory, different points in time. A wormhole is much like a tunnel with two ends, each in separate points in spacetime.

For a simplified notion of a wormhole, space can be visualized as a two-dimensional (2D) surface. In this case, a wormhole would appear as a hole in that surface, lead into a 3D tube (the inside surface of a cylinder), then re-emerge at another location on the 2D surface with a hole similar to the entrance. An actual wormhole would be analogous to this, but with the spatial dimensions raised by one. For example, instead of circular holes on a 2D plane, the entry and exit points could be visualized as spheres in 3D space.

10 things you should know about black holes

“At this point in time, we are certain that black holes exist, we know where they are, how they form, and how they’ll eventually, on timescales of 10^67 years and up, cease to exist. But the details of where the information that went into them goes are still up for grabs, and that’s one of the problems unique to black holes among all objects in the Universe.”

Earlier this week, Stephen Hawking shook up the world when he announced that he had uncovered the solution to the black hole information paradox at a conference in Stockholm. When particles fall into (or create) a black hole, information is encoded on the black hole’s surface, but when the black hole decays into radiation, that information appears to be lost, as the radiation is thermal. But perhaps the information is stored on the event horizon, and can be encoded into the outgoing radiation thanks to the interplay of gravitation and matter. Details should be forthcoming in a paper to be released next month by Hawking, Malcom Perry and Andrew Strominger.

Forget the past, live the present, dream the future.

Maritina Christofilakou

A galaxy cluster or cluster of galaxies is a structure that consists of anywhere from hundreds to thousands of galaxies bound together by gravity.[1] They are the largest known gravitationally bound structures in the universe and were the largest known structures in the universe until the 1980s when superclusters were discovered.[2] One of the key features of clusters is the intracluster medium or ICM. The ICM consists of heated gas between the galaxies and has a temperature on the order of 7-9 keV. Galaxy clusters should not be confused with star clusters such as open clusters, which are structures of stars within galaxies, as well as globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as groups of galaxies rather than clusters of galaxies. The groups and clusters can themselves cluster together to formsuperclusters.

Buzz Aldrin inside the Gemini 12 spacecraft, November 13, 1966.

(NASA/University of Arizona)

A new study of fossilized dinosaur embryos suggests that the young of these prehistoric animals were slow to develop, with some spending up to sixth months inside their eggs before hatching. Detailed in the journal Proceedings of the National Academy of Sciences, this drawn-out development cycle not only surprised scientists—it may have contributed to the downfall of the dinosaurs.

“We know very little about dinosaur embryology, yet it relates to so many aspects of development, life history, and evolution,” said study co-author Mark Norell, Macaulay Curator of Paleontology at the American Museum of Natural History. “This work is a great example of how new technology and new ideas can be brought to old problems.”

Using a combination of computed tomography (CT) scanning and powerful microscopes, Norell and colleagues from the University of Calgary and Florida State University examined the teeth of fossilized dinosaur embryos in unprecedented detail, shining new light on specimens about which not much is known.

Read more about this new research on the blog. 

Spleens are strange organs, located on the upper-left side of the abdomen behind the stomach. They’re about the size and shape of an orange wedge, if the orange was squishy and full of blood. They’re relatively fragile, and because they contain so much blood, injuries can become serious.

A very informal poll of NPR employees, friends and random Uber drivers reveals that most people don’t have any idea what spleens are for. If they did know anything about spleens, it was this: You don’t need one to live.

The deep red, squishy spleen has been relegated to the organ bargain-basement, something to be cut out and discarded along with the appendix and wisdom teeth. But the spleen is seriously underrated, and we would like to give it a chance to redeem itself.

Meet The Spleen, The Strange Little Organ That Can Multiply

Image: Science Source

Stephen Hawking: 'If you feel you are in a black hole, don’t give up. There’s a way out.'

All is not lost if you fall into a black hole – you could simply pop up in another universe, according to Stephen Hawking.

The celebrated physicist has a new theory about where lost information ends up after being sucked into a black hole, a place where gravity compresses matter to a point where the usual laws of physics break down.

In a public lecture in Stockholm, Sweden, Prof Hawking said: “If you feel you are in a black hole, don’t give up. There’s a way out.” He said he had discovered a mechanism “by which information is returned out of the black hole”.

He was speaking at the KTH Royal Institute of Technology, where the Nordic Institute for Theoretical Physics (Nordita) is hosting the Hawking Radiation Conference dedicated to examining the mystery of the “information paradox” – a conundrum concerning what happens to things swallowed by black holes.

Information about the physical state of something disappearing into a black hole appears to be completely lost. But according to the way the universe works, this should be impossible. Even information falling into a black hole ought to end up somewhere.

According to Hawking, it does – in one of two ways. Either it is translated into a kind of “hologram” on the edge of the black hole, or it breaks out into an alternative universe.

In his lecture, reported in a blog from the KTH Royal Institute of Technology, he said: “The existence of alternative histories with black holes suggests this might be possible. The hole would need to be large and if it was rotating it might have a passage to another universe. But you couldn’t come back to our universe. So although I’m keen on space flight, I’m not going to try that.

“The message of this lecture is that black holes ain’t as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole both on the outside and possibly come out in another universe.”

Hawking is director of research at Cambridge University’s department of applied mathematics and theoretical physics.

• This article was amended on 27 August 2015. An earlier version said the KTH Royal Institute of Technology was hosting the conference.

Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but would account for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, on radiation, and on the large-scale structure of the universe. Dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics.

Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.[2][3] Thus, dark matter is estimated to constitute 84.5% [note 1] of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total mass–energy content of the universe.[4][5][6]