Category: Ars Technica
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Electron, heal thyself! Making curved electron beams go around barriers
Electron beams, like light, spread out when they pass through an opening. Even highly focused beams such as lasers spread over large distances, a result of the wave character of light. However, by manipulating the wave form near its source, researchers can create something known as an Airy beam, which doesn’t disperse—and in fact follows…
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New exoplanet is smaller and hotter than Mercury
We often focus on the search for Earth-like planets (whatever that means) when we talk about exoplanets: planets orbiting other stars. However, another important goal is to categorize as many planetary systems as possible, determining what kind of planets orbit what sort of stars. That catalog is gradually revealing the way planets form, and how…
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Weird supernova marks the spot of a violent outburst…and black hole
Any core-collapse supernova—the explosion of a massive star—is by nature powerful, destructive, and rare. The really dramatic supernovas have the extra effect of exploding in a non-spherical way, beaming a lot of their matter and energy along an axis. When Earth is aligned with those beams, we see the supernova as a gamma ray burst…
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High-energy cosmic rays are sped on their way by exploding stars
Where do cosmic rays originate? Cosmic rays are mostly high-energy protons from deep space that hit Earth’s upper atmosphere, creating showers of other particles that can be detected at the surface. Some of these protons are so incredibly high energy—meaning they’re moving just a whisker slower than the speed of light—that only exceptional astronomical events…
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Kaboom! A simulation shows how impacts shaped and nearly destroyed Vesta
Vesta is the second-largest asteroid in the Solar System, and recent measurements by the Dawn mission showed that it’s actually a protoplanet: a piece of planet-like material left over from the early days of our Solar System. However, Dawn is significantly non-spherical and very battered. Most notably, it has two huge overlapping craters near its…
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Playing a quantum shell game to win
The shell game is a classic con, a rigged contest meant to separate a person from their money. The quantum shell game described in a new paper is meant to elucidate the role of measurement in the outcome of an experiment, separating the quantum and classical aspects clearly. This was accomplished using measurement of the…
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Stellar epidemiology: predicting supernovas from death throes of stars
Astronomers would love to predict supernovas: knowing when and how massive stars die would reveal a great deal about them. An observation of a particular supernova with the license-platish name SN 2010mc actually began 40 days before the final explosion, giving astronomers a lot of data about the final stages of its life. This type of…
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When the reverse of reverse isn’t forward: weird symmetry in uranium compound
Typically, reversing the direction of time twice is the same as never reversing it at all. Think of running an old-fashioned filmstrip backward, then forward (not an unusual experience for those of us um…of a certain generation): the film will look the same as though you never ran it backward. However, a particular uranium compound,…
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Accelerating neutral particles on a lab bench
Most accelerators, including the big ones at CERN and RHIC, use charged particles: protons, electrons, or ions (atoms with electrons removed to make them positively charged). That’s because it’s easy to accelerate that kind of particle using electric and magnetic fields. However, neutral particles like neutrons or normal atoms can’t be accelerated by those fields,…
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Rapid cooling of semiconductors using lasers (but no sharks)
Laser cooling (also known as optical cooling) is a well-established technique…but mostly for gases. The basic idea is to disperse the thermal energy of the atoms through shining light on them: the frequency of the laser is set to be slightly lower than the energy of transition between two configurations in the atoms, so that…
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