Where are all the (intelligent) aliens?
Calculations say there should be evidence of alien life in our own solar system!
On the Habitability of the Kepler 16 System
George Lucas dreamed of a planet with two suns. Now that Kepler scientists have found such a planet, the question arises: can it support life?
Where in space are the faster-than-light neutrinos?
Several weeks ago, the OPERA experiment announced that they had measured neutrinos travelling faster than the speed of light. The neutrinos, which traveled from CERN to the Gran Sasso Laboratory, arrived at the detector 60 nanoseconds earlier than light (with statistical errors of 6.9 ns and systematic errors of 7.4 ns).
Wishy-Washy Water World
When we dream of other worlds, there is one thing that drives our fantasies of life above all else: water. Most organisms on Earth rely on this molecule for survival. Although we might imagine life forms that do not require water, planets with water are the most obvious places to search for life—or at least for life as we know it.Thus, the discovery of the first potential “water world” in 2009 was a turning point in exoplanet science. At the time, I was a senior at Harvard University working with David Charbonneau, whose team and their robotic telescopes discovered the super-Earth GJ 1214b when it transited its star. In a Nature publication, Dave describes the discovery.The planet is just the right density to be made entirely of water. However, the discovery of GJ 1214b only suggests its watery nature; the planet could have a dense, rocky core and a large but light atmosphere of hydrogen and helium instead.To distinguish between these possibilities, several groups have performed transmission spectroscopy. This technique measures the starlight that passes through the planet’s atmosphere while the planet transits its star. By measuring the light transmitted at different wavelengths, it is possible to construct a spectrum of the planet’s atmosphere. Absorption and emission lines in the spectrum can reveal chemicals in the atmosphere.Counter-intuitively, the scientists studying GJ 1214b are not looking for spectral lines due to water. Models show that adding water vapor to the atmosphere of GJ 1214b would flatten the spectrum, smearing out all features. However, a high layer of clouds could also produce such a spectrum, so a flat spectrum does not...