Buzz Aldrin Inside The Gemini 12 Spacecraft, November 13, 1966.

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]

How Close Are We To Nuclear Fusion?

“Naysayers love to claim that nuclear fusion is always decades away — and always will be — but the reality is we’ve moved ever closer to the breakeven point and solved a large number of technical challenges over the past twenty years. Nuclear fusion, if we ever achieve it on a large scale, will usher in a new era for humanity: one where energy conservation is a thing of the past, as the fuel for our heart’s desires will literally be without limits.”

The ultimate dream when it comes to clean, green, safe, abundant energy is nuclear fusion. The same process that powers the core of the Sun could also power everything on Earth millions of times over, if only we could figure out how to reach that breakeven point. Right now, we have three different candidates for doing so: inertial confinement, magnetic confinement, and magnetized target fusion. Recent advances have all three looking promising in various ways, making one wonder why we don’t spend more resources towards achieving the holy grail of energy.

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.

Is Everything We Know About Universe Wrong?

A very interesting documentary about the Universe.

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. 

The Andromeda Galaxy (/ænˈdrɒmɨdə/), also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth.[4] It is the nearest major galaxy to the Milky Way and was often referred to as the Great Andromeda Nebula in older texts. It received its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda. Being approximately 220,000 light years across, it is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and about 44 other smaller galaxies.

The Andromeda Galaxy is the most massive galaxy in the Local Group as well.[7] Despite earlier findings that suggested that the Milky Way contains more dark matter and could be the most massive in the grouping,[12] the 2006 observations by the Spitzer Space Telescope revealed that Andromeda contains one trillion (1012) stars:[9] at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion.[13]

The Andromeda Galaxy is estimated to be 1.5×1012 solar masses,[7] while the mass of the Milky Way is estimated to be 8.5×1011 solar masses. In comparison, a 2009 study estimated that the Milky Way and M31 are about equal in mass,[14] while a 2006 study put the mass of the Milky Way at ~80% of the mass of the Andromeda Galaxy. The Milky Way and Andromeda are expected to collide in 3.75 billion years, eventually merging to form a giant elliptical galaxy [15] or perhaps a large disk galaxy.[16]

At 3.4, the apparent magnitude of the Andromeda Galaxy is one of the brightest of any Messier objects,[17] making it visible to the naked eye on moonless nights even when viewed from areas with moderate light pollution. Although it appears more than six times as wide as the full Moon when photographed through a larger telescope, only the brighter central region is visible to the naked eye or when viewed using binoculars or a small telescope.

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.