Green cells are undergoing cell death, a cellular division-of-labor--fostering new life. Images

More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals. Just how that happened is a question that has eluded evolutionary biologists.

We've started searching our Kepler SETI observations and our analyses have generated some of our first candidate signals. Each of the signals below is shown in a pair of plots, one from an observation of Kepler Object of Interest (KOI) 817 and one from an observation of KOI-812. During an observation, we alternated between targets to enable us to rule out signals seen coming from two different places in the sky. If we see a signal coming from multiple positions on the sky, like the ones below, it is very likely to be interference. The signals below are undoubtedly examples of terrestrial radio frequency interference (RFI).

Using powerful magnets to levitate fruit flies can provide vital clues to how biological organisms are affected by weightless conditions in space, researchers at The University of Nottingham say.

IMAGE CAPTION: An illustration of what early Earth may have looked like several billion years ago. (Copyright 2011 Don Dixon/cosmographica.com)

Two University of Colorado Boulder researchers who have adapted a three-dimensional, general circulation model of Earth's climate to a time some 2.8 billion years ago when the sun was significantly fainter than present think the planet may have been more prone to catastrophic glaciation than previously believed.

This diagram compares our own solar system to Kepler-22, a star system containing the first "habitable zone" planet discovered by NASA's Kepler mission. The habitable zone is the sweet spot around a star where temperatures are right for water to exist in its liquid form. Liquid water is essential for life on Earth.

With the successful launch of the Mars Science Laboratory on Saturday, Los Alamos National Laboratory researchers and scientists from the French space institute IRAP are poised to begin focusing the energy of a million light bulbs on the surface of the Red Planet to help determine whether Mars was or is habitable.

In a finding of significance in the search for life beyond Earth, scientists have discovered what appears to be a body of liquid water the volume of the North American Great Lakes locked inside the icy shell of Jupiter's moon Europa - which could represent a new potential habitat for life.