From Mark McWilliams:

Re: Moon systems, not planets, may be place to find aliens (Feb. 19): Higher life as we know it requires liquid water so any intelligent life to develope on one of these moons would require a moon about the size of Earth.

I enjoyed your article on the search for life on moons except I believed it was a little deceptive in that it implyed that intelegent life might be able to move from one small moon to another.

I did a study / display in a multidisciplinary class in college and in my research a planet as small as Mars is not likley to have much/any liquid water on it. Mars is about half the diameter of Earth (actually a tiny bit more). Based several calculations to figure volume, mass, atmospheric pressure and such it is my belief that Mars has NEVER had much liquid water on it if it ever had any.

This idea was first based on the idea that on Earth as you gain altitude water boils at a lower temperature due to the lower air pressure. I don’t remember how I figured that water would boil at about 45 degrees Fahrenheit (actually a bit less) but it had to due to the atmospheric pressure on Mars which is a small fraction (about 1%) that of Earths. I don’t remember how I got that number at this time But I know I either confirmed it or had the calculations checked by a teacher who would have promply pointed out any errors. Based on this, water on Mars can only exist in a liquid form on the surface at temperatures between 32 and 45 degrees Fahrenhiet and it would escape the planet at a about 100 degrees Fahrenhiet. Higher life as we know it requires liquid water so any intelligent life to develope on one of these moons would require a moon about the size of Earth.

The whole display I made ended up being on the uniqueness of the Planet Earth. How small it is and the space between planets & how no other planet in our solar system comes close to supporting life. The model could only display the inner solar system with the Sun being 60 inches in Diameter and Earth being 1/2 an inch and the moon 1/8th inch & 1 foot away & Earth about 450 feet from the sun. The idea that the moon plays a very important part in life on Earth by keeping the Earths core molten (due to gravitaional forces) which helps create the magnetosphere keeping harmfull radiation from us.

The search/discovery of extrasolar planets is based on the idea of gravitational pull on the star by the planet(s). THis idea may mave some yet unforseen flaws in it and I would like those with the tools and ability to study our own star to see if they can confirm Jupiter which should be large enough at 1/10 the diameter &. 001% the mass of the Sun.

I hope this wasn’t long/boring/whatever & I hope to see an article about the search for life on Europa some time in the near future. I believe that you do not need to drill through the ice but examine the ices on the surface to see if there is evidence of life under the ice.