Superbugs from Hell - Evolution Re-Visited

If there is, or was, life on Mars, then it raises a fascinating possibility. Back in the early history of the Solar System, the heavy bombardment that made conditions on the planets so dangerous for surface life would also have kicked vast numbers of rocks out into space. Many Mars rocks must have reached Earth during our planet's history, and many ejected Earth rocks will have hit Mars. Could hardy superbugs dwelling within these rocks have hitched a ride through space and taken up residence on arrival?

Current evidence strongly suggests the answer is yes, and that Earth and Mars cross-contaminated each other billions of years ago. It's even conceivable that life began on Mars and travelled to Earth some time later in meteorites, colonising our planet when conditions eventually became favourable. If so, we are all descended from Martians!

The Garden of Eden - Revisited

Tantalising though these developments are, the problem remains of how the first living cell formed. What chemical magic triggered the vital spark? Whether the key process happened on Mars, Earth, or both, the puzzle of the chemical genesis of life is still unsolved. Armed with the new ideas, however, researchers are now focusing their efforts on the chemistry of hot rocks infused with sea water. Might the gases exuded by a planet's crust offer a more potent mix than those of the primordial atmosphere? Could the pores in ocean basalt play the role of tiny crucibles, in one of which was forged that microbial Adam long, long ago? Some scientists think so, and are increasingly hopeful that the key steps will soon be understood.

In many cultures the underworld has long been associated with the realm of the dead. For Christians, it is the traditional location of Hell, a place of fire and brimstone, and eternal torment. How ironical if the torrid, sulphurous depths actually harboured the cradle of life. Far from being Hell, the broiling bosom of our planet might well turn out to have been the true Garden of Eden.

For more information

Video: Birth of the Earth [Firstscience presents]
How was the Earth created? Our planet now supports a huge diversity of living creatures requiring very special conditions, but what was the series of events that brought this unique set of conditions together?

Video: Was Darwin Wrong? [FirstScience presents]
From the air to the depths of the oceans our planet teems with life. To some, it's a miracle – but can science explain the diversity of animals and plants?