See the first photos of September's majestic total lunar eclipse.
The greatest challenge facing astrobiologists is that there is only one planet known to us that has life. Of all the bodies of the Solar System, only Earth has a dense atmosphere, liquid water on its surface, and the organic chemistry that supports life. However, these conditions did not exist billions of years ago when Earth was still young. While the nebula from which the planets formed was rich in volatile elements, the high temperatures in the inner Solar System largely prevented them from condensing, leaving them mostly in a gaseous state.
