As our astronomers search for signs of extraterrestrial life in the Universe, a new study shows there could be aliens on at least 9 planets beyond our Solar System watching the human race right now.
Scientists are not saying they have discovered any advanced extraterrestrial civilization, but they do state that our planet and all its inhabitants may be observed by aliens who possess the right technology.
Astronomers scientists from Queen’s University Belfast and the Max Planck Institute for Solar System Research in Germany have identified parts of the distant sky from where various planets in our Solar System could be seen to pass in front of the Sun – so-called ‘transit zones’. Based on their data they concluded that extraterrestrials have a better chance to observe rocky planets including Earth than the gas and ice giants Jupiter, Saturn, Uranus and Neptune that are further from the Sun.
In the journal Monthly Notices of the Royal Astronomical Society astronomers write that nine, if not more exoplanets are ideally placed to observe transits of Earth.
”Larger planets would naturally block out more light as they pass in front of their star”, commented lead author Robert Wells, a PhD student at Queen’s University Belfast. ” However, the more important factor is actually how close the planet is to its parent star – since the terrestrial planets are much closer to the Sun than the gas giants, they’ll be more likely to be seen in transit.”
To look for worlds where civilisations would have the best chance of spotting our Solar System, the astronomers looked for parts of the sky from which more than one planet could be seen crossing the face of the Sun. They found that three planets at most could be observed from anywhere outside of the Solar System, and that not all combinations of three planets are possible.
Katja Poppenhaeger, a co-author of the study, adds,”We estimate that a randomly positioned observer would have roughly a 1 in 40 chance of observing at least one planet. The probability of detecting at least two planets would be about ten times lower, and to detect three would be a further ten times smaller than this.”
Of the thousands of known exoplanets, the team identified sixty-eight worlds where observers would see one or more of the planets in our Solar System transit the Sun. Nine of these planets are ideally placed to observe transits of Earth, although none of the worlds are deemed to be habitable.
In addition, the team estimate that there should be approximately ten (currently undiscovered) worlds which are favorably located to detect the Earth and are capable of sustaining life as we know it. To date however, no habitable planets have been discovered from which a civilization could detect the Earth with our current level of technology.