Earth sows its seeds in space

February 23, 2004 | Source: Nature Science Update

Deep-frozen spores that spread life in space (the Panspermia concept) could survive if they can escape the Sun’s gravity more quickly. And that might happen if the rocks they sit on are first ground to dust, says William Napier, an astronomer at the Armagh Observatory in Northern Ireland.

The pressure of sunlight can quickly blow grains this small out of the solar system and such a grain could travel about six light years from Earth in 70,000 years, far enough to reach other stars. We could be surrounded by a huge “biodisk” of frozen organisms floating on grains of rock that wander in and out of our solar system.

Earth should spread its seed widest when we pass through a giant molecular cloud, a mass of dusty material from which stars are born. This has happened about five times since life appeared on Earth and could also account for how the Earth wound up hosting life.