What makes a planet habitable

Artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System.

Which of Earth's features were essential for the origin and sustenance of life? And how do scientists identify those features on other worlds?A team of investigators with array of expertise ranging from geochemistry to planetary science to astronomy published this week an essay in Science urging the research community to

Life May Have Evolved Before Earth Finished Forming

Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist's conception.

Life may have arisen in our solar system before Earth even finished forming.Planetesimals, the rocky building blocks of planets, likely had all the ingredients necessary for life as we know it way back at the dawn of the solar system, said Lindy Elkins-Tanton, a planetary scientist at Arizona State University (ASU).And