Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.
New Scientist: One of the primary methods used to encrypt information involves the generation of large, nonreproducible random numbers that serve as the key. Because purely numerical algorithms can be reproduced, physical processes are often used as the basis for the keys. Now Jeffrey Lee and Gerald Cleaver of Baylor University in Waco, Texas, have shown that the cosmic microwave background (CMB) radiation left over from the Big Bang can be one of those processes. The reason the CMB works as a random-number generator is that measurements made by one observer of the strength of the signal from a specific area of the sky can never be duplicated exactly by another observer, even when made in exactly the same way at exactly the same time. Several measurements can then be combined to generate a large random number. Because of the expense and logistics involved in operating a radio telescope, however, only governments or large organizations would have the necessary resources to use cosmology as an encryption method.
Ars Technica: As is becoming tradition at CERN's Large Hadron Collider (LHC) at this time of year, the proton–proton collisions that were used to find the Higgs particle have been put on hiatus so heavy-ion collisions can be studied. On 25 November, the LHC began firing lead nuclei against each other and immediately achieved record levels of collision energy. The resulting quark–gluon plasma provides glimpses into the nature of the strong force, which binds quarks into hadrons and governs hadron interactions. In previous years when the LHC has switched to heavy-ion collisions, the data have served to verify work previously done at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory in New York. This year's collisions will extend that work and perhaps reveal more evidence about recently discovered pentaquarks or other theoretical and unexpected particles.
The Independent: Although dark matter can't be seen, its existence is inferred from its gravitational effects on visible matter. According to models created by Gary Prézeau of NASA's Jet Propulsion Laboratory and his colleagues, unlike regular matter, dark matter can pass through planets, and as it does, it gets squeezed into networks of "ultradense filaments." Those filaments are hair-like, with densely concentrated roots and thinner ends that extend away from the planets. Prézeau says that modeling the dark matter could provide clues about where to look for it. To maximize the chance of detecting it, he proposes sending probes into orbit around other, more massive planets, such as Jupiter, where the network of such dark-matter hairs is likely to be denser.
Ars Technica: A wide range of animals use Earth's magnetic fields to migrate every year, but the mechanism by which they detect those fields has been unclear. Now Chinese researchers have identified a protein in the Drosophila fruit-fly genome that binds to iron, which can detect polarity. Called the Drosophila magnetoreceptor protein, dMagR is found inside cells that have light-sensing proteins called cryptochromes, used by birds to identify magnetic field lines. The resulting complex is capable of detecting the polarity, intensity, and inclination of Earth's magnetic field and has an inherent magnetic moment. The researchers also found the same complex in humans as well as in other animals, such as pigeons and mole rats.
Ars Technica: This morning, Blue Origin announced that yesterday it launched its New Shepard rocket to an altitude of 100.5 km and returned it safely to the launch site. It is the first rocket to achieve this task. The ability to reuse hardware could cut the costs of access to space or high-altitude flight substantially. Space X has been working on a similar technique for the first stage of its Falcon 9 rocket, but has had only limited success. Blue Origin's New Shepard combines a booster with a pressurized crew capsule, and its video of the launch suggests that the company intends to use New Shepard for space tourism: Passengers riding in the crew capsule would be lifted into space for a brief period of weightlessness, then the capsule would deploy a parachute before returning to Earth.
New Scientist: Maximizing the amount of material that can be included in space launch cargos is a significant task—boxes and other items have already been converted into flat sheets that take up less space in the cargo and can be assembled in orbit. Lynn Rothschild of NASA's Ames Research Center and her colleagues have now gone one step further by taking the plastic sheets out of the equation entirely. They genetically engineered Escherichia coli bacteria to produce polystyrene and P(3HB) plastics. After the plastic is processed into sheets, a black marker is used to draw lines on them; when the sheets are placed under IR light, the dark areas contract and the sheets fold along the lines. The team also experimented with attaching Bacillus spores to cellulose strips that are strategically placed on the plastic. The spores expand and contract based on changes in humidity, causing the plastic to bend. Further work is needed to make the process practical. Intentionally sending E. coli bacteria to space is risky, however, because they could contaminate the food supplies.