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Space

Frigid Brown Dwarf Found Only 7.2 Light-Years Away 142

Posted by Soulskill from the interstellar-stalker-hiding-in-the-bushes dept.
An anonymous reader writes "Astronomer Kevin Luhman just found the 7th closest star to the sun. It's a mere 7.2 light-years away, discovered using NASA's Spitzer and WISE telescopes. How could it exist so close for so long without us knowing? It's a brown dwarf — barely a star at all. 'Brown dwarfs are star-like objects that are more massive than planets, but not quite massive enough to ignite sustained fusion in their cores. Hydrogen fusion is what powers the Sun, and makes it hot; it's the mighty pressure of the Sun's core that makes that happen. Brown dwarfs don't have the oomph needed to keep that going.' This small almost-star is downright chilly at around 225-260 Kelvin. That's -48 to -13 C (or -54 to 9 F). As Phil Plait points out, that's not much different from the temperature in the freezer in your kitchen. He adds, 'It implies this object is very old, too, because it would've been a few thousands degrees when it formed, and would take at least a billion years to cool down to its current chilly temperature. It's hard to determine how old it actually is, but it's most likely 1-10 billion years old. It has a very low mass, too, probably between 3 and 10 times the mass of Jupiter. That's pretty lightweight even for a brown dwarf. And here's another amazing thing about it: It might be a planet. What I mean is, it may have formed around a star like a planet does, then got ejected by gravitational interactions with other planets.'"
Science

Making Graphene Work For Real-World Devices 18

Posted by Soulskill from the more-better-faster-lighter-cheaper dept.
aarondubrow writes: "Graphene, a one-atom-thick form of the carbon material graphite, is strong, light, nearly transparent and an excellent conductor of electricity and heat, but a number of practical challenges must be overcome before it can emerge as a replacement for silicon in electronics or energy devices. One particular challenge concerns the question of how graphene diffuses heat, in the form of phonons. Thermal conductivity is critical in electronics, especially as components shrink to the nanoscale. Using the Stampede supercomputer at the Texas Advanced Computing Center, Professor Li Shi simulated how phonons (heat-carrying vibrations in solids) scatter as a function of the thickness of the graphene layers. He also investigated how graphene interacts with substrate materials and how phonon scattering can be controlled. The results were published in the Proceedings of the National Academy of Sciences, Applied Physical Letters and Energy and Environmental Science."
Science

Fossils of Earliest Known Pterosaur Found 18

Posted by Soulskill from the death-from-the-skies dept.
damn_registrars writes: "A fossil of the earliest known Pterosaur flying reptile was found recently in China. Named Kryptodrakon progenitor, it was described in a paper published yesterday in the journal Current Biology (abstract). Its wingspan was about a meter and a half, very small compared to its evolutionary descendents, whose wingspan reached over 10 meters. 'The pterosaurs remained largely unchanged for tens of millions of years — with characteristics like long tails and relatively small heads — and none became very big. But later during the Jurassic period, some developed anatomical changes that heralded the arrival of a new branch called pterodactyloids that eventually replaced the more primitive forms of pterosaurs. Many of these pterodactyloids had massive, elongated heads topped with huge crests, lost their teeth and grew to huge sizes. Perhaps the defining characteristic of the group is an elongation in the bone at the base of the fourth finger called the fourth metacarpal, and Kryptodrakon is the oldest known pterosaur to have this advance, the researchers said.'"

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