## Friday, January 14, 2005

### Greetings from Saturn's moon

This ESA/NASA project for 3+ billions dollars

will hopefully be probing Titan, a moon of Saturn, momentarily. The probe (Huygens) has landed successfully and it should be sending data to the spaceship (Cassini). Freeman Dyson has kind of predicted - and let me emphasize that his analyses are based on a very rational thinking, although the assumptions are far-fetched - that sophisticated plants will parabolic leaves that collect solar radiation may live somewhere around there. But even if the more boring scenarios, or - as others would say - if the common sense prevails, one could get some interesting pictures for the prize of 2+ LHC colliders.

1. Let me just remark that Dyson is definitely not a crack pot. He gave a seminar about his ideas in Cambride and he is well aware of the fact that his ideas here are extremely far fetched and that it is unlikely that they are true. But he makes the nice observation that if there were life in the outer regions of the solar system that draws its energy from the sun, it should have large sun light collectors. Their area has to grow with the square of the distance from the sun to collect sufficient energy. It just turns out that therefore the amount of light reflected back to sun is thus _independant_ of their distance to the sun and thus they might be observable (if existant) if one look exactly away from the sun.

According to Dyson, hunters in scandinavia use this this trick: They point a flash light into the dark and if there is some aninal that looks into the light its eyes reflect the light back to the hunter and she can find the animals this way.

Dyson has some other speculations about life in the liquid oceans under some thick layer of methan ice on some moon of Saturn or Jupiter (Titan?), is that what you are refering to?

2. "Dyson has some other speculations about life in the liquid oceans under some thick layer of methan ice on some moon of Saturn or Jupiter (Titan?), is that what you are refering to?"

I think you mean saline water ocean under water ice, on the Europa moon of Jupiter.

Quoting http://www.space.com/scienceastronomy/solarsystem/europa_ocean_000824.html:
"Data collected earlier this year by the Galileo spacecraft has now generated what some scientists are calling virtually undeniable evidence that Jupiter’s moon Europa has a significant water ocean churning beneath its icy surface.

The data, which was collected by Galileo’s magnetic-field-detecting instruments when the spacecraft flew close to the icy moon, showed that there is an electrically charged layer of some substance stirring possibly as close as 4.7 miles (7.5 kilometers) below the moon’s ice crust."