A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma (a thin, fuzzy, temporary atmosphere) and sometimes also a tail. Occasionally, they will collide with planets such as the Earth. New research from Lawrence Livermore National Laboratory scientists shows that comets that crashed into Earth millions of years ago could have produced amino acids – the building blocks of life. Amino acids are critical to life and serve as the building blocks of proteins, which are linear chains of amino acids.