Astrobiology is the study of life in space, like on other planets or moons, or even outside of the solar system. Astrobiologists study how life began and evolved on Earth, and how it might exist in other places. They use mathematics, chemistry, and physics to figure out the conditions necessary for life, and to search for signs of it. Astrobiologists often work with biologists and astronomers to understand the big picture of life in the universe.