Are we all Martians?

But others think that primitive life could have reached our planet aboard a meteorite that crashed on Earth billions of years ago – and which could have originated from Mars. At one point, extremely hot temperatures on the red planet cooled down and were conducive to life. Rocks from the asteroid belt often collided with Mars, causing pieces of the planet to launch into space, and the sun’s gravity could have pulled them to Earth. The study of a famous Martian meteorite found in Antarctica in 1984 showed that the meteorite had not been heated to inhospitable temperatures when it was dislodged from the planet – in fact, it never reached a temperature above 40 C (104 F).

But could microbes and bacteria inside these meteorites have survived the extreme turbulence of their journey through space? An experiment by an international team of scientists has recently shown that they could withstand the impact. They collected colonies of micro-organisms and placed them in rocks similar to the ones found on Mars, and then simulated the pressure caused by a landing on Earth. Explosives were used to fire a steel plate at the rocks at pressures of up to 45 billion pascals – a real crush considering that the pressure in a car tire is about 200,000 pascals. Surprisingly, the bacteria survived pressures as high as 10 billion pascals.

Although this is far from proof that life came from Mars, it is another piece of evidence in its favour. There is not much research done on the origin of life, despite it being such a profound topic and seemingly a fundamental one if we are to truly understand nature. Since it’s unlikely that science will be providing us with concrete answers anytime soon, I guess we must satisfy ourselves with the fact that we’re here – and that we could indeed be Martians.

For more information

Video: Birth of the Earth [Firstscience presents]
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Video: Close Encounters [Firstscience presents]
Has planet Earth ever had a close encounter with aliens? We investigate some of the most popular and controversial scientific topics of our time.

The Guardian - Microbe experiment suggests we could all be Martians http://www.guardian.co.uk/uk_news/story/0,,1989431,00.html

SPACE.com - Panspermia: Spreading Life Through the Universe http://www.space.com/searchforlife/seti_panspermia_030724.html