Now this may be an impossible problem. We can study astrobiology and we can investigate how life might have formed, but no one was there taking notes when life formed. But by insight on this, you can at least look at what the starting materials were. So that's what Stardust is going to do, look at the starting materials, what was around in the solar system before life existed on Earth. That's an appropriate thought, Brownlee said.
Comets are a vehicle that brings organic materials to the Earth.
Many of the carbon atoms in our bodies were in comets early in the history of the solar system. So one of the bylines of the Stardust mission is that we are stardust. Our bodies are actually made of stardust. Science aside, there's a hint of romanticism about this mission.