Calling all extraterrestrials

 

Sir, – I enjoyed the article “There’s a high chance aliens are out there, so why haven’t we met them yet?” (November 3rd) but offer a word of warning: while I have no doubt that life exists elsewhere in the universe on planets with water and air, I would be very doubtful it would be in a form with which we could communicate.

Earth was formed about 4.5 billion years ago and the first evidence of life on Earth comes from fossil bacteria found in rocks more than three billion years old. Hominids of which we human beings are one species, did not evolve until a few million years ago. It took literally billions of years. If Earth’s age was imagined to be one year, then hominids appeared at about 11.55pm on December 31st.

What’s more, the evolution of life has been a very chancy thing. During those three billion years, the forward progress has been punctuated by a succession of mass extinctions, some as high as 94 per cent of all living species.

If the only real evidence we have of extraterrestrial life is the presence in recent meteorites of primitive bacteria which resemble those that started the process of evolution on Earth three billion years ago, I think the chances of meeting extraterrestrial beings with our precise characteristics are negligible.

– Yours, etc,

Prof CHRIS STILLMAN,

Glenageary, Co Dublin.