They are a far cry from the little green men that science fiction fantasies are made of. But, if NASA, the American space agency, is right, the ultimate question has been finally answered, and we are not alone in this universe.
Perhaps relieved that the first firm sign of extra-terrestrial life took a more friendly form than the aliens who blew up the White House in the hit movie Independence Day, President Clinton was quick to welcome the evidence of fossils in a four-billion-year-old meteorite that may have come from Mars. He called it potentially one of the most stunning scientific discoveries ever made.
As if determined not to be outdone by this, a Beijing biologist yesterday revealed that China has its own historic fossils, which prove that sex has been around for a lot longer than anyone realised. For good measure, a Xinhua (the New China News Agency) dispatch then rubbished the US discovery as unreliable.
Yet Xinhua is right to urge caution. All that has been found so far are carbonate compounds which can also be created by car exhaust. Nor is there any firm evidence that the meteorite did, in fact, come from Mars. NASA's conclusions may have ultimately prove to have far-reaching ramifications. After all, if there was life on Mars, there is no reason why it cannot also exist on other planets. But further evidence is needed before rushing to reassess our view of the universe.
Even then, if all Earth's inhabitants have got for company is a single-cell organism, that probably became extinct on Mars several billion years ago, then we can be forgiven for feeling almost as alone as before.