Is the rest of the cosmos a pristine environment awaiting the arrival of humanity’s “post-human” descendants? Or is advanced life there already – and if so has it visited us? These questions rate as some of the most fascinating in science.
They bring to mind the theme of science-fiction classics like Steven Spielberg’s ET. Now, though, amid the fanfare surrounding his new film, Departure Day, Spielberg himself has said he believes that aliens exist.
So do I, though I’m sceptical of Spielberg’s belief that we’ve been visited here on Earth. Proclamations of UFO sightings, abductions, and so forth never seem convincing.
Indeed, the space age brought sobering news about habitats in our Solar System. Venus, a cloudy planet that promised a lush tropical world, turned out to be a crushing, caustic hell-hole.
Mercury was a pock-marked blistering rock. And a series of robotic orbiters and landers has revealed that Mars, though the most Earth-like body in the Solar System, is actually a frigid desert with a very thin atmosphere.
With those facts in mind, finding even simple life beyond Earth would be a mega-discovery. Probes are now embarked (or, in the case of the latter, will soon be embarking) on the several-year journey to Jupiter’s moon Europa, and Saturn’s moon Enceladus. Yet nobody can be optimistic: certainly there’s no expectation of advanced life anywhere in the Solar System away from the Earth.
But the likelihood of alien life brightens enormously when we extend our gaze beyond our Solar System – to the realm of the stars, far beyond the reach of any space probe we can devise today.
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