Astronomers are learning much more about how planets are created. They now have a growing collection of new observations of other planets in other planetary systems. Some of those systems are very young and still not finished forming. Some others push the envelope of what scientists thought was even possible. The astronomers are combining this new data with powerful new computer simulations, allowing them to explore just what it takes to build a stable planetary system from a collapsing cloud of stardust.
One new feature: when solar systems are first formed around baby stars, some orbits are more crowded than others. Just like on a busy freeway, there are “planet pileups” and “planet deserts", rush hours and empty stretches, and it takes a little time to get the traffic jams all sorted out.
Computer simulations have helped reveal plausible explanations for phenomena that have long puzzled astronomers, like why the gas giants Jupiter and Saturn ended up just where they are, or why rocky planets like Mercury, Venus, Earth, and Mars ended up where they are closer to the Sun.
Read the full article.