First British astronaut says aliens are here

By Ewan Jones, SciTech Editor

According to the famous story, Enrico Fermi and three of his fellow physicists were having lunch at the Los Alamos laboratory when Fermi suddenly exclaimed “where is everybody?”. After getting over the shock of his outburst, the four began discussing the subject of his puzzlement: where are all the aliens? 

His argument is as follows: the Milky Way has billions of Sun-like stars, and there is a high probability some have Earth-like planets suitable for the evolution of intelligent life. Given that many of these similar stars are billions of years older than the Sun, and even with the frustrating speed-limit set by light, intelligent civilisations should have had plenty of time to develop interstellar travel and reach Earth. So where are they?

Where are all the aliens?

According to the first British astronaut, Helen Sharman, it’s possible that aliens are “here right now and we simply can’t see them”. Speaking to the Observer, Sharman remarked that “aliens exist, there’s no two ways about it”, with a justification Fermi would be proud of, that “there are so many billions of stars out there in the universe that there must be all sorts of different forms of life”. These forms, however, may not be made up of the stuff of Earth life, carbon and nitrogen, but could be formed from completely foreign chemistry, such as the popular example of silicon-based life. 

Aliens exist, there’s no two ways about it

Silicon, like carbon, has the potential to form four covalent bonds with other atoms, which is the basic requirement for an element to take the form of a ‘building block of life’. In fact, in 2016 researchers at Caltech were able to breed a bacteria capable of making bonds with silicon, the first example of this process being performed by an organism. These non-carbon-based lifeforms could potentially exist as a microbial ‘shadow biosphere’, passing right under our noses as we frantically search for beings that fit our anthropic view of what constitutes ‘life’.

If there is a plethora of life formed from different chemical elements, Dr Frank Drake would probably be overjoyed. He pioneered the famous ‘Drake Equation’, which uses a number of estimates for factors contributing to the development of intelligent civilisations to estimate the total number of these civilisations in the Milky Way with which we could communicate. The equation contains such components as “average rate of star formation”, “fraction of planets that could support life that then go on to develop it”, and “length of time for these civilisations to release signals into space”, in addition to others. 

The Milky Way has billions of Sun-like stars, and there is a high probability some have Earth-like planets suitable for the evolution of intelligent life

Once each constant is derived, the equation comes to an estimate of 1000 to 100,000,000 intelligent, communication-friendly civilisations in our galaxy. Many critics claim this number is a massive overestimate, however if Helen Sharman’s ‘shadow biosphere’ exists, perhaps Drake was spot on with his estimate of a galaxy teeming with life, and the answer to Fermi’s famous question is that we just can’t see them?

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