Liquid Water Is the Key to Living Things

As the analysis of the data transmitted from Mars Explorer Odyssey launched by NASA confirmed the existence of ice-lake in Mars, the possibility of the existence of living things on Mars is likely to bring about a big disputes among scholars, who believe that the existence of liquid water is the key to the existence of living things.

The exploration of the first Mars explorer Mariner IV in 1965 sent back a negative sign for the existence of living things. 22 photos sent by Mariner IV showed craters on Mars made by the collisions with meteorites. The atmosphere pressure seemed hardly to hold liquid water in the air and an ozone layer was not enough to protect the life forms on the surface of Mars.

However, as Mariner IX in 1971, Viking I, II in 1976, and Surveyor still operating on Mars since 1996 discovered the traces of water stream on the surface, the disputes about the existence of living things on Mars have been heated up. Particularly, a valley found by Surveyor in 2000 was similar to the terrain created by the overflowing of subterranean water. However, some scholars refuted that such terrain could be made by the liquid of dry ice as well.

In addition, an evidence for the existence of life forms was found last December 2000 in a meteorite from Mars found 15 years ago at the South Pole. The meteorite contained a magnetite crystal that is known to be formed by the marine bacteria on earth.

The discovery of the ice-lake on Mars proves that Mars had abundant water in the past and living things could have lived there. And it could be possible that a certain life form may live in the liquid water on Mars until today. NASA wants to collect soil samples from Mars to find the liquid water and a living thing.

cosmos@donga.com