Although it's only one part of the answer, we have come another step closer to solving the question of how life originated. Two necessary molecular ingredients of DNA and RNA have been confirmed to have originated from outer space. They join the handful of amino acids we have discovered to have been delivered to Earth on the backs of asteroids and comets. Publishing in the journal Earth and Planetary Science Letters, the team of research scientists from the US and Europe have demonstrated that uracil and xanthine are present in fragments of the Murchison meteorite and are not terrestrial in origin. Studies of the Murchison meteorite, which crashed in Australia in 1969, are routinely criticized over concerns of Earthly contamination.