Atom & Cosmos

Moons may be common, plus transforming neutrinos, new comet images and more in this week’s news

Rosetta captures first comet image
The European Space Agency’s Rosetta mission, set to become the first craft to observe a comet close up for an extended period of time, has taken its first images of Comet Churyumov-Gerasimenko. At a distance of 163 million kilometers,from the craft, the comet appears only as a faint point of light, but the glimpse confirms that the onboard camera is operating. Rosetta won’t catch a second look at this pristine relic from the solar system’s formation for another 31 months, when the solar-fueled craft awakens from an energy-conserving period of hibernation that began June 8. In November 2014, the craft will release a small lander onto the comet’s icy nucleus. —Ron Cowen

Black holes, galaxies linked in time
New observations suggest that black holes and galaxies have grown in tandem throughout cosmic history, not just in recent times as previous studies had shown. Ezequiel Treister of the University of Hawaii in Honolulu and his colleagues used observations of X-rays, which penetrate the shrouds of gas and dust that bury many early black holes, to find that these beasts were more common and grew faster than thought in galaxies that existed when the universe was less than a billion years old. Future observations of such early growth are likely to reveal which of two scenarios for the origin of supermassive black holes is correct, the researchers report in the June 16 Nature. —Ron Cowen

Moons galore
Just as Earth comes with a relatively big moon, more than one in 12 Earthlike planets may host a similarly big satellite that helps stabilize the planet’s rotation. New calculations of collisions among the embryonic solar system’s debris suggest that a pairing like the Earth and moon isn’t as uncommon as scientists had thought, a team from the University of Zurich in Switzerland and the University of Colorado at Boulder write in an upcoming Icarus. The gravitational pull of a big nearby moon helps keep a planet from tilting too much on its axis, allowing climate to remain relatively hospitable for life. —Alexandra Witze

First muon neutrino transformation
Japan’s Super-Kamiokande has become the first detector to find evidence that muon neutrinos transform into electron neutrinos, researchers announced June 15. (Neutrinos can oscillate among three types, or “flavors”: electron, muon and tau.) The finding gives physicists a new way to explore possible differences in how neutrinos and antineutrinos carry out these transformations, which might explain why the universe ended up with so much more matter than antimatter. Between January 2010 and March 2011, when it was halted by the Japanese earthquake, Super-Kamiokande found that six out of 88 muon neutrinos in a beam traveling 295 kilometers had transformed into electron neutrinos. —Ron Cowen

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