Source: Grok AI
Once upon a time we knew our place in the universe. The science was settled and the experts agreed. The Earth was at the centre of the universe and everything we could see in the sky revolved around us. Anyone claiming otherwise was a heliocentric bigot and geocentric denier (probably a far-wrong racist too).
This view held sway for over 1,400 years, mainly as it was the only way to explain why the relative positions of the stars stayed the same, which common sense says that they wouldn’t if the Earth was spinning around the Sun.
Copernicus made the first hole in the intellectual dams with his 1543 “Six Books Concerning the Revolutions of the Heavenly Orbs” (nothing to do with tassles on a burlesque dancer – that hadn’t been invented yet). There were still critical gaps in his thinking – he couldn’t for example, explain why we didn’t all get tossed off as the Earth spun around on its axis – but scientists quickly started to realise that he was onto something.
Fast forward to 1961, a year momentus for two reasons. Firstly, I was born and, of lesser note, America astrophysicist Frank Drake attempted to quantify the number of extraterrestrial lifeforms that could be discovered. Drake was part of the SETI (Search for Extra-Terrestial Intelligence) group, which included future luminaries like Carl Sagan.
Rather than bore you with the formal equation (which act would include me learning how to do subscripts in Open Office and life’s too short for that), Drake’s equation just multiplies together a set of numbers as follows:
Number of civilisations in the Milky Way with which we could possibly communicate =
- the rate at which stars are formed, multiplied by
- the fraction of those stars that have planets, multiplied by
- the average number of planets that could support life per star that has planets, multiplied by
- the fraction of planets that could support life which go on to actually support life, multiplied by
- the fraction of planets that support life which becomes intelligent, multiplied by
- the fraction of civilisations that release detectable signs of their existence into space, multiplied by
- the length of time for which those civilisations emit detectable signs.
The problem for anyone trying to come up with an answer here is pretty obvious – we don’t know what values to plug into most of these variables and any change in one value is immediately compounded by the multiplication with all of the other values.
Given that we only have one example of intelligent life (humans) we could assume, for example, that every planet that develops life goes on to produce intelligent life which goes on to emit detectable signs of its existence into space, but clearly that would be a bit naive.
The starting assumptions made by Drake and his colleagues gave a range for planets in the Milky Way with civilisations from 1,000 to 100,000,000. Helpful.
A few things have changed since those initial estimates. One key thing (which was on my geeky bucket list) is that we have found exoplanets, that is, planets orbiting a star other than our Sun. In fact it is looking increasingly likely that all stars of a type like our Sun have at least one planet around them, which potentially stabilises one variable in the equation to a simple value of one.
One other school of thought (the “Rare Earth hypothesis” crowd) suggests that the combination of factors that led to life arising on Earth was so unusual that three variables in the Drake equation multiply together to give a value of 0.0000000000001, meaning that we are not only the only life in the Milky Way but also in the observable universe.
A perhaps more realistic set of assumptions give the answer that there are 15,600,000 other civilisations out there.
My personal and deeply unscientific opinion is that the universe is so mind-buggeringly vast that to think that our planet is the only one where a only bunch of single-cell organisms got together and had such wild sex that multi-celluar organisms ensued is arrogant beyond reason.
The downside of having a big universe where every planet is a very, very long way away from every other one is that the chance of our civilisation being advanced and inclined to look for intelligent life in the exact bit of the universe where another civilisation was sending its own version of Naked Attraction into space however many light years ago they did it are effectively zero.
So, are we alone as intelligent beings in the universe? Absolutely not.
Will we ever get evidence to prove it? Almost certainly not.
I really do wish we would though … imagine the possibilities of what that first message might say.
© Northern Man 2025
