Tuesday, October 26, 2004

Cassini- Huygens Mission to Saturn

In about 3 hours, Cassini-Huygens spacecraft will fly to within 200 miles of the surface of Saturn's moon Titan. Titan is really huge- bigger than Mercury or Pluto- and its atmosphere (a moon with an atmosphere!) may resemble that of the early Earth.
I do not have a full grasp of the pros and cons, but I have seen arguments that during the earliest days of the solar disk that would later become our solar system, the vicinity of Earth's current orbit would too hot to contain complex organic molecules, or evenwater (as ice). This line of thought proposes that ice and organics coalesced into planetoids further out, at Jupiter's orbit and beyond, and were much later thrown inward by the slingshot gravitational actions of the growing Jupiter and Saturn. Others were thrown out to create the current Oort cloud, the orbital source of new comets.
Thus early Earth (and early proto-life) may have been supplied with materials similar to those still in cold storage on Titan. I believe the two limitations of this scenario are that planetoid collisions with the forming Earth would have had huge energy, and would probably incinerate the kind of molecules we associate with life. Secondly, Titan has had its own geological history over the last 4 By and may be cratered or gravitationally modified. However, combined with observations of new comets I think we can get a picture of what raw materials were available on Earth during the emergence of life.

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