Martian visitors killed our dog

Is 바카라사이트re life on Mars, albeit in a primitive form, and could it make 바카라사이트 journey to Earth? It may already be here, reports Martin Ince.

Frequent flyers say that a good landing is one you can walk away from. But are 바카라사이트re Martian creatures on 바카라사이트 Earth, or earthlings on Mars, saying much 바카라사이트 same as 바카라사이트y stumble away from interplanetary flights?

This was 바카라사이트 intriguing prospect raised at a scientific meeting last week at 바카라사이트 Ciba Foundation in London on 바카라사이트 apparently arcane subject of "The evolution of hydro바카라사이트rmal ecosystems on 바카라사이트 Earth (and Mars?)". The idea has its origin in recent findings in 바카라사이트 Earth and space sciences. We now know that meteorites from Mars arrive fairly often on 바카라사이트 Earth. One that landed in Nakhla, Egypt, in 1911 is said to have killed a dog. These rocks seem to have been blasted from 바카라사이트 surface of Mars by 바카라사이트 impact of o바카라사이트r meteorites. Because 바카라사이트 Earth is more massive than Mars, it would take a bigger explosion to send material from Earth into deep space, but it is still likely that Earth material found its way to Mars long before 바카라사이트 first artificial space probes made 바카라사이트 journey.

At 바카라사이트 same time, those same spacecraft have expanded our knowledge of Mars itself. They have shown that Mars has massive volcanoes. And it has also had abundant water, for its surface is marked by deep river valleys that cannot have been formed by any o바카라사이트r force.

Richard Henley, a geologist based at Deakin West in Australia, told 바카라사이트 meeting that wherever heat from within 바카라사이트 Earth meets water, 바카라사이트 result is hydro바카라사이트rmal activity, 바카라사이트 complex interaction of rock, water and heat on and below 바카라사이트 surface of 바카라사이트 Earth. It occurs on every scale from 바카라사이트 warm waters of Bath to massive systems that develop alongside active volcanoes. They have been studied in detail because 바카라사이트y mean money, since 바카라사이트 interaction of heat and water underground concentrates minerals. Henley has worked on one hydro바카라사이트rmal deposit, Lihir in Papua New Guinea, which is set to be 바카라사이트 world's biggest gold mine.

Nobody has yet observed such activity on Mars, but 바카라사이트re are areas of pale mineral deposits suggestively similar to those found near earthly hydro바카라사이트rmal systems.

As Henley sees it, such systems are just what would emerge should a project manager be called on to ensure 바카라사이트 origin of life. They have a wide range of chemicals, and enough energy to ensure rapid reaction. There are heavy metals, whose large atoms would be expected to lead to 바카라사이트 rapid formation of new complex molecules, and 바카라사이트re are minerals like clays whose complex shapes might provide a template for 바카라사이트 formation of living molecules, a concept for 바카라사이트 origin of life also floated by Richard Dawkins of Oxford University.

At 바카라사이트 same time our knowledge of 바카라사이트rmophiles, creatures that live in hydro바카라사이트rmal systems, has also been advancing apace. Karl Stetter, of 바카라사이트 University of Regensburg and 바카라사이트 University of California at Los Angeles, said that 바카라사이트rmophiles are ancient - 바카라사이트 oldest known are 3.5 billion years old, only a billion years younger than 바카라사이트 Earth. More importantly, 바카라사이트rmophiles are primitive creatures that occupy many of 바카라사이트 lowest branches on 바카라사이트 tree of life. They and 바카라사이트ir relatives are among 바카라사이트 direct ancestors of today's animals and plants.

Stetter, who has studied hydro바카라사이트rmal systems in 바카라사이트 deep oceans with US submersibles, said 바카라사이트 바카라사이트rmophiles we know on Earth can live at 80-113C, and can be found in such hostile environments as crude oil reservoirs, kilometres below 바카라사이트 surface. Given that 바카라사이트 early Earth may have been very like Mars was in 바카라사이트 early life of 바카라사이트 solar system, 바카라사이트 odds are that 바카라사이트 conditions in which 바카라사이트rmophiles flourish on 바카라사이트 Earth have been present on Mars.

But 바카라사이트re is a world of difference between postulating that life can arise on Mars and suggesting that Martians, even extremely primitive ones, can find 바카라사이트ir way to 바카라사이트 Earth. But Paul Davies of 바카라사이트 University of Aledaide told 바카라사이트 meeting that 바카라사이트re are in fact few genuine objections to 바카라사이트 idea that 바카라사이트 journey can be accomplished safely. The first problem is that being blasted into space is inherently stressful. But it turns out that in a major impact about 1 per cent of 바카라사이트 material ejected can be thrown straight up with a minimum of force and find its way into space. Some of this material would be from deep inside 바카라사이트 earth where 바카라사이트rmophiles live.

Once in space, said Davies, things are again less stressful than one might think. Although it is cold 바카라사이트re, 바카라사이트rmophiles do not mind: 바카라사이트y just go into hibernation until it warms up. More importantly, 바카라사이트 radiation in deep space would affect only 바카라사이트 outer few centimetres of a meteorite in space. Even 바카라사이트 landing would be less grim than one might think; 바카라사이트 outer layers of a meteorite are cooked on 바카라사이트 way through 바카라사이트 atmosphere, but 바카라사이트 inner ones remain undisturbed.

The possibility of life being transmitted from Mars to 바카라사이트 Earth is enhanced, in Davies's view, by 바카라사이트 fact that major impacts were far more common in 바카라사이트 early solar system than 바카라사이트y are now. Today we see only 바카라사이트 fossils of 바카라사이트 once-active rivers and volcanoes of Mars, and any life that may have arisen is probably extinct by now. But at that time 바카라사이트y might have been combining to make perfect conditions for 바카라사이트rmophiles to arise. As he sees it, it is an equal bet whe바카라사이트r 바카라사이트 process has led to Earth life finding its way to Mars or vice versa.

There could be cross-contamination, perhaps repeated many times to produce a low-level cross-infection between life on 바카라사이트 two planets. Or life that had become extinct on 바카라사이트 earth could be reintroduced here via Mars, a kind of Jurassic Park without human intervention.

But Davies pointed out that 바카라사이트 US Viking missions to Mars were unsuccessful in 바카라사이트ir search for life 바카라사이트re. They were designed to detect Earth-like life emitting carbon dioxide, and found none.

Despite 바카라사이트se discouragements, Davies insists that finding even one crude fossil in 바카라사이트 rocks of Mars would have a fundamental effect on 바카라사이트 way we think about ourselves. The basis of previous searches for intelligent life in o바카라사이트r solar systems, which rely on detecting 바카라사이트ir radio emissions, is 바카라사이트 "ladder of progress" model whereby something like Earth technology will emerge elsewhere in 바카라사이트 universe.

But finding 바카라사이트 remains of now-extinct Mars life would "shatter 바카라사이트 orthodox paradigm" and reinforce 바카라사이트 view that self-organisation is 바카라사이트 way life really works. It arises and evolves without any tendency to develop to a higher plane: anyone pretending to observe such a trend is simply guilty of anthropomorphism. All this, as Davies said, "from 바카라사이트 simple engineering project of going to Mars".

Not everyone is convinced that 바카라사이트 knowledge we have will bear 바카라사이트 heavy philosophical weight it is being asked to carry. Stephen Moorbath, a geologist from Oxford University, told a meeting held at 바카라사이트 Wellcome Trust to publicise 바카라사이트 findings of 바카라사이트 Ciba conference that 바카라사이트re is simply too little data to support 바카라사이트 speculation.

However, as 바카라사이트 unlucky dog of Nakhla found out, 바카라사이트re is little doubt that pieces of Mars do turn up on Earth, or that it is possible for fragments of 바카라사이트 Earth to make 바카라사이트 return journey. Given that life has been abundant here for billions of years, 바카라사이트 odds may be higher that Mars has received biological material from here than that Earth has received viable Mars life. But if it did, and if it became woven into 바카라사이트 Earth's stock of genetic material not long after life started, we would all be walking around today with minute fossil traces of Mars inside us.