Is there anyone out there? How would we know?
If there is an alien civilisation, it is probably on a planet circling a star, right? There are an estimated 200 billion trillion stars in the universe. A lot, right? So how come we have found no evidence for any other intelligent life?
I’d always assumed that evidence could come from the use of the electromagnetic spectrum for purposes such radio and television broadcasts and mobile communications. These signals would propagate through space for ever and we ought to be be able to detect them.
But, in an interesting article, Robin McKee, of the “Guardian” newspaper, quotes Chris Lintott, of Oxford University, as follows:
“We have relied in the past almost exclusively on radio telescopes to detect broadcasts from alien civilisations just as our radio and TV transmissions could reveal our presence to them. However, to date, we have heard absolutely nothing.”
Nor should we be surprised, Lintott argues. “Humanity has already passed its peak radio wave output because we are increasingly using narrow beam communications and fibre-optic cables, rather than beaming out TV and radio signals into the general environment.”
Humanity could become radio-quiet in about 50 years as a result – and that will probably be true for civilisations on other worlds, he added. “They will have gone radio silent after a while, like us. So Seti radio telescopes will need to be augmented with other ways of seeking aliens. We are going to have to be more creative about what we’re searching for in the data and find unusual things that reveal they are the handiwork of aliens.”
It could well be that we’ll never know if there is other life in the universe.