Ancient Planets

03_Sussman_WA_Stromatolites_1211_05122Another day, another major development in humanity’s rapidly advancing search for Life elsewhere in the universe. You’ll recall from previous posts that scientists have discovered more than 1,700 exoplanets orbiting distant stars over the past few years. Now comes news that astrophysicists have discovered five Earth-sized terrestrial exoplanets that are more than 11 billion years old. The discovery has a couple implications. First, scientists have long assumed that stellar material must pass through at least two generations in order to forge the heavy elements of which terrestrial planets, and life, are comprised. The discovery that planets coalesced relatively soon after the Big Bang (13.8 billion years ago) means that we may need to rethink our most basic assumptions about planetary formation. Second, the discovery means that life could have sprouted when the universe was still in its infancy. After all, scientists believe that life appeared on Earth relatively soon after the planet coalesced (4.6 billion years ago). If our sample size of one is any indication, and the same proved true for any one of these five planets, then there could be life forms in the galaxy that are more than twice as old as life on Earth. Pretty heady stuff. To learn more, check out the links here (paywall), here, and here. Meanwhile, if you want to learn more about the oldest living things on Earth (and, so far as we know, in the Universe), check out Rachel Sussman’s fascinating research at this link.