Solar System Date of Birth Determined

Invisible Pink Unicorn writes "UC Davis researchers have dated the earliest step in the formation of the solar system — when microscopic interstellar dust coalesced into mountain-sized chunks of rock — to 4,568 million years ago, within a range of about 2,080,000 years. In the second stage, mountain-sized masses grew quickly into about 20 Mars-sized planets and, in the third and final stage, these small planets smashed into each other in a series of giant collisions that left the planets we know today. The dates of these intermediary stages are well established. The article abstract is available from Astrophysical Journal Letters."