Aliens could be watching us from 29 different planets, astronomers reckon
Humanity has spent a lot of time looking for signs of extraterrestrial life, but less time has been spent pondering whether alien life could be looking for us – until now.
Astronomers in New York have narrowed down the list of places where aliens could be watching us to just 29 potential planets.
These planets were selected from a potential 1,715 star systems in our neck of the Milky Way where an alien civilisation could have witnessed the Earth crossing the face of the Sun – the most common tool to discover other planets.
This shortlist was then narrowed down even further to those that are close enough to intercept radio and TV signals since we began broadcasting them, around 100 years ago.
Planets that were both in the right position to measure our existence and intercept our signals turned out to be rather few – given we’ve yet to find any evidence of extraterrestrial life so far, it appears unlikely that these 29 planets could have been watching us.
But ufologists and alien watchers will point out that we’ve only visited a handful of planets in our own Solar System – if any of those civilisations hadn’t yet developed communication tools, they could be in a position to watch us.
There is also the question of whether we’ve been visited by aliens already – which the hotly anticipated Unidentified Aerial Phenomena Task Force report in the US looks to shed some light on tomorrow.
The researchers, publishing their method in Nature, didn’t comment on the possible of existence of aliens, instead, they asked – if they did exist, where might they be watching us from?
Cornell University astronomy professor and co-author of the study Lisa Kaltenegger told The Guardian: ‘Who would we be the aliens for if somebody else was looking?’
‘There is this tiny sliver in the sky where other star systems have a cosmic front seat to find Earth as a transiting planet.’
In the search for extraterrestrial intelligent life (SETI), scientists have discovered thousands of planets around other solar systems – so-called exoplanets – using the method of ‘transit’ or ‘Doppler spectroscopy’.
The technique proved so successful that the first exoplanet discovered using this method won its practitioners the Nobel Prize in Physics.
The James Webb Space Telescope, a more advanced and technically capable space observatory than its famous predecessor, the Hubble Space Telescope, is due to be launched this year.
It’s hoped that by using techniques like analysing the composition of exoplanet atmospheres, we might be able to find alien life sooner rather than later.
There is little known about the planets that Kaltenegger and her colleague Jacqueline Faherty deemed most likely for alien watchers.
A close (in galactic terms) star to us, Trappist-1, has at least seven planets, with four in the ‘Goldilocks zone’ that could make them hospitable to life – but it won’t be able to see the Earth transiting across the Sun for at least 1,642 years.