Atom & Cosmos

How to hunt for extraterrestrials, plus cosmic bursts, horseshoe orbits and more in this week's news

Cosmic burst source fingered
New simulations affirm that two dead stars merging into a black hole can shoot out some of the universe’s most powerful eruptions. These “short gamma-ray bursts” unleash in under a second the energy the Milky Way emits in one year. Using supercomputer simulations, an international research team watched two neutron stars spiral into each other and collapse into a black hole surrounded by a doughnut of material threaded with a superstrong magnetic field. As the doughnut coalesced, the magnetic field reorganized itself, becoming 1,000 times stronger than the stars’ original fields and forming a pair of funnels that could launch the high-energy jets associated with such bursts, the researchers propose in the May 1 Astrophysical Journal Letters. —Camille Carlisle

Too darned quiet
A researcher has a new suggestion about why it’s so hard to find advanced extraterrestrial life: They’re afraid to advertise. Adrian Kent of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, suggests that intelligent species might reasonably worry about the dangers of self-promotion and incline toward discretion rather than broadcasting their presence. He notes that evolutionary selection tends to extinguish species that conspicuously broadcast their habitat. Kent posted his study online April 5 at —Ron Cowen

Searching for E.T. miners
Earth-based observers might be able to see the evidence of asteroid mining by distant civilizations, an international team proposes. If an advanced civilization depleted resources on its own planet and began mining nearby asteroids, the team argues in an upcoming International Journal of Astrobiology, the chemical composition, shape and size distribution of objects would change in the parent star’s debris disk, the dusty disk continually replenished when asteroids and their fragments collide. Although such signatures are not unique to mining, they would indicate that a nearby star system should be examined more closely for signs of life. —Ron Cowen

A less lively Titan
Wind, rain and erosion can account for all surface features on Saturn’s moon Titan, with no evidence of icy volcanism — cold material erupting from beneath the surface, images taken by the Cassini spacecraft reveal. Researchers who had thought that some land forms were created by icy volcanism proposed that such activity might provide a supply of liquid water for organisms that would have access to the moon’s abundant supply of organic compounds. The lack of volcanism also suggests that Titan’s hydrocarbon lakes can’t be replenished by an underground source and will dry up — perhaps in some 30 million years — NASA scientists report in the April Icarus. —Ron Cowen

Asteroid in a horseshoe orbit
A newly discovered object that has hewed close to Earth’s path for at least the last 250,000 years is the largest of only three asteroids with an orbit that resembles a horseshoe as viewed from Earth. Asteroid 2010 S016 is either a leftover from the formation of the inner planets or a refugee from the main asteroid belt between the orbits of Mars and Jupiter. The object could shed light on planet formation in the inner solar system, researchers at the Armagh Observatory in Northern Ireland report in an upcoming Monthly Notices of the Royal Astronomical Society. —Ron Cowen

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