Exoplanet collisions are common...and play key roles in solar system developement

In a Distant Galaxy, Colliding Exoplanets Are Upending What We Knew About Solar System Formation

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Solar systems form in a school of hard knocks.

Take ours, for example: Earth had barely cooled 4.5 billion years ago when it got slapped in the face by a renegade Mars-size rock, reducing both bodies to giant balls of lava. Scientists believe this cosmic collision spewed so much debris into the air that it eventually coalesced into Earth's moon — a beautiful partnership born from chaos.


Collisions like these are common in young solar systems, but become much rarer as time rolls on: Large planets fall into line and host stars either swallow or blow away smaller chunks of debris. Now, NASA astronomers think they may be witnessing a violent exception to that pattern in a solar system far, far away.