extraterrestrial life

Are we alone in the Universe? There are billions of stars in our galaxy, and 100 billion galaxies in our Universe. We don't know how many planets there are, or how many of these planets might have life on them. We've found some planets outside our solar system, but none seem to have conditions needed for life.

Evidence: so far, there is no evidence of life anywhere in the Universe but on Earth
Current Research: we're looking for extra-solar planets, searching for water on other planets in the solar system, monitoring radio waves from deep space, and learning to recognize what life might be like elsewhere by studying life in
extreme environments on Earth
Importance: to help us understand our origins and who our neighbors might be

Image credits: main image, © AMNH/Jim Steck and Daryl Collins; Neil Tyson: AMNH.