Images from the cosmic delivery room
Images of newborn planets, still embedded in gas and dust, challenge our previous theories on the formation of the celestial bodies.
Thousands of exoplanets are now known - and in most cases they are arranged differently than in our solar system. Here the small rocky planets are close to the sun, while large gas planets drift further out through space. The majority of exoplanet systems discovered to date do not show such a clear pattern. Things have gotten even more complicated since researchers started observing protoplanetary disks directly. "We see all kinds of structures there," says US astronomer Kate Follette from Amherst College in the US state of Massachusetts. The timing also seems to be different than long suspected: "Even in discs that we thought were too young for planets to form, they seem to be forming."
Interestingly, the prevailing theory of the birth of our solar system goes back to Immanuel Kant. In 1755, the German philosopher imagined that the sun and its planets could have formed from a nebula of gas and dust. Researchers still see it in a similar way today: According to this, the sun emerged from the collapsing part of a molecular cloud, the material of which produced several stars. For a while, the sun was still surrounded by a ring of gas and dust, which slowly cooled and condensed into growing granules. The latter then formed larger and larger bodies and finally asteroid-sized objects called planetesimals, from which the planets ultimately formed …