MEDIA hype, the silly season, a much needed publicity campaign by NASA, or one of the most stunning scientific discoveries of our time? You pays your money and you takes your chances... but already William Hill in London has cut the odds against finding intelligent life on Mars from 500 to 1 to 25 to 1, while the price of meteorites is set to rocket.
Although the possible implications are already being considered, the scientific debate about whether there once was primitive life on Mars has only begun.
And what is the evidenced In essence, the nine scientists from five American institutions claim to have found both complex chemical compounds and microscopic structures on a meteorite.
Analyses of the meteorite suggest it came from Mars, that the rock in it is 4.5 billion years old, that it was ejected from Mars following a massive impact 15 million years ago, and that it fell to Earth 13,000 years ago.
Within fractures in the rock, the scientists found carbonates (such as you find in limestone), which date to 3.5 billion years ago. Although the carbonates themselves are no indicator of life, they do indicate the presence of liquid water, at temperatures which would support life (0-80c), and from a time when primitive life forms are known to have existed on Earth and when the climate on Mars was warm and wet.
Within the carbonates, they found particles of magnetite and iron sulphide, similar to those produced by bacteria on Earth. Magnetite and iron sulphide are produced by opposing types of reactions (what chemists call reduction and oxidation), which normally occur together only where there is life.
On the carbonate surfaces they found complex organic chemicals, containing carbon ring structures (polycyclic aromatic hydrocarbons, PAHs). These are associated on Earth with the breakdown of living organisms, but they can also be produced chemically. However, the presence on the meteorite is significant in its own right, as it is the first time such compounds have been found on extra terrestrial material.
Perhaps most eye catching of all was the pictorial evidence. For, again on the carbonate surfaces, the scientists also found many tiny structures some round, some elongate which they say could be the fossil remains primitive organisms, not unlike bacteria, although some 10 times smaller than any known on Earth
The team, led by NASA's David McKay, acknowledges that "none of these observations is in itself conclusive" but taken together, we conclude they are evidence for primitive life on Mars'.
Significantly, a British team which has been studying material from the same meteorite had concluded that the structures were due to chemical alterations of the meteorite and not to life.
Not surprisingly, the sceptics have already been voicing their and decisions have been described as everything from premature to downright wrong.
Dr Nigel Monaghan, geology curator with the National Museum in Dublin, is not surprised. "There was the same scepticism when scientists first said they'd found similar primitive fossils in very old rocks on Earth." These are preserved as simple strings of spheres, in rocks 3.5 billion years old.
THOUGH initially sceptical, Dr Cyril Smythe, a microbiologist at Trinity College, Dublin, having read the scientific paper (see panel), was full of praise for what he said was cautious and thorough research. "They've answered any initial questions, about whether there might be contamination," he told The Irish Times yesterday.
Dr Tom Mason, director of Armagh Planetarium and a geologist who has spent 20 years studying early fossils on Earth, said the pictures were less than convincing, but this could be because of the type of rock. Confidently identifying such structures would be very tricky.
But then who knows what to look for? No one has done this before, and the only thing we have to go on is our experience of life on Earth. If Martian life is any different, who's to say we'll recognise it.
The NASA led team itself admits that the picture is complicated because we do not know where the rock originally came from on Mars. However, Dr Mark Bailey, director of Armagh Observatory, suggested that, since the impact which dislodged the rock must have been massive, it should be possible to locate the impact crater.
Certainly, more research will be needed. Already, NASA is suggesting it will analyse the meteorite for traces of amino acids and look for traces of structures (such as cell walls) within the so called fossil bacteria. Comparisons will no doubt he made with terrestrial fossils of a similar age.
There will be renewed pressure on the forthcoming missions to Mars, but NASA is strapped for cash. Cutbacks in recent times have meant that, for example, there are no back ups for some of the instruments on the two missions which NASA will launch later this year. (The last Mars mission, launched in 1992, went missing just days from the planet's surface, leading some to suggest it had been captured by Martians.)
The clincher, however, could only come from analyses of rock returned from Mars, but such a mission is not yet possible, though there is pressure from NASA director, Dan Gold in, to try for one in 2003.
If David McKay and his colleagues are right then, at the very least, Mars and the Earth shared a common early history. It could also mean that there is life, on Mars today, however primitive and hidden from view raising many ethical and scientific questions.
If there was once life there, then it could mean that life, far from being a rare occurrence, will actually arise anywhere provided the conditions are right. Or it could mean that life arose once, on one of the planets, spreading to the other on a meteorite, although no one knows whether a living organism could survive the journey intact. (The meteorite, ALH 84001, was tested for living organisms, but none were found, though that could mean we didn't know what to test for.)
On Earth, living organisms are continually being found in extreme conditions where once it was thought life could not exist (unusual life forms may yet be found in the massive lake which lies beneath the Antarctic ice sheet), and there is growing evidence for the existence of planets around other stars. Ours is probably only an ordinary, planet, around an ordinary star, in an ordinary galaxy.