Category: Ars Technica
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Cannibal binary star could explain mysterious nova-like outbursts
A mystery: an unknown star, too faint to notice, suddenly expanded to a huge size, increasing in brightness to become one of the most luminous stars known. This star doesn’t even have a real name, just a “license plate” catalog number: V838 Monocerotis, indicating that it’s a not very important star in the constellation the…
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Turning graphene into an AC/DC quantum ratchet
Just as a ratchet allows rotation in one direction but not the other, quantum ratchets break the symmetry of a microscopic system to facilitate preferential motion in one direction or another. Graphene is a two-dimensional hexagonal lattice of carbon atoms. As such, it’s highly symmetrical, but beneath that lurks a potentially exploitable hidden asymmetry. If…
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In Soviet Russia, material compresses *you*
Most solids compress when squeezed, though the effect isn’t very large for most technologically important materials (metals, ceramics, and so forth). A few rare materials exhibit negative compressibility: they expand in the direction the force is exerted, though again the effect is small. However, researchers figured out a way to produce extraordinarily large negative compressibility,…
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Boosting solar cell efficiency with wires smaller than the wavelength of light
Researchers working on the next generation of photovoltaic solar cells—cells that convert sunlight directly into electrical current—are looking toward exotic materials (which are expensive) or more common substances, but use subtler methods to extract energy. A new study used a basic semiconductor material, already in use in solar cell research, but made it into a…
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Straight outta Compton…
(This was my original title for my article, but my editors evidently didn’t like it. I guess I’m too old school. Ahem. Moving right along.) As you may know, quantum physics shows that matter has both a wavelike and particle-like character. When you combine quantum physics and special relativity, you find that a particle at…
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4,096 miniature antennas on a chip send shaped light
Phased arrays consist of multiple antennas, all driven from a single source. By combining the output from all those antennas, you can make the light very directional, or give it a particular shape. Typically, phased arrays use radio light: big radar installations use them, as does the Very Large Array (VLA) of radio telescopes. A…
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Maybe you could be the one to discover the next Earth
The orbiting Kepler observatory has been a remarkably successful project since its inception. By watching one small patch of the sky continuously, Kepler has enabled astronomers to discover upward of 2300 possible exoplanets—planets orbiting other stars. While many of those candidates likely are not actually planets, follow-up observations have confirmed 854 exoplanets as of December…
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Bad news for some planets in binary star systems?
How quickly things can change in science: just a few years ago, we were barely able to talk about the diversity of planetary systems. Now, we are able to distinguish between planets orbiting in tight binary systems from those in wide binaries. Additionally, exoplanets in tight binaries can orbit either both stars together (circumbinary, or Tatooine-like…
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Why do half of Andromeda’s satellite galaxies orbit in a plane?
Our local group of galaxies—known imaginatively as the Local Group—has two huge galaxies: the Milky Way and M31, also known as the Andromeda Galaxy. Both of these galaxies are large enough to have a number of satellites, including the substantial Magellanic Clouds and M33 (Triangulum Galaxy). However, most satellites are dwarf galaxies, very faint and…
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