Earth has been around for 4.8 billion years. It's a long time and one scientist believes it's an unusually long time not to have visitors.
Through the years, scientists with the Search for Extraterrestrial Intelligence or SETI have not found any evidence on the existence of extraterrestrial life.
Now, according to Live Science, a SETI researcher is suggesting that there's a chance an advanced alien species have been spying on Earth all this time by hiding a probe on one of the Earth's so-called co-orbitals.
E.T. May Have Been Spying On Earth
In a research paper published in the Astronomical Journal, physicist and independent SETI researcher James Benford explained that a nearby group of co-orbital objects is the ideal spot to observe Earth from a distance.
Co-orbitals are objects that orbit the sun at roughly the same distance as Earth, which means that some of these objects are going around the sun at the same rate as the planet while being very nearby.
If it's true that aliens bugged a co-orbital to observe Earth, there might be traces of their presence left on these space objects, even if they're long gone by now. Earth's co-orbitals could be astronomers' window into ancient alien activity, which is the basis of the new proposal to explore co-orbitals for advanced alien technology.
Scientists could begin to engage in a study that Benford described to Live Science as "extraterrestrial archaeology."
He added that if scientists don't find anything from nearby bodies, it would mean that no civilization has looked at Earth in over billions of years. According to Benford, this prospect would be extremely surprising, considering how long the planet has been around.
Unlikely, But Not Impossible
Scientists acknowledge that it's a long shot to expect results on one of these expeditions to co-orbitals, but even skeptics are not against taking a closer look at these space objects.
"How likely is it that alien probe would be on one of these co-orbitals, obviously extremely unlikely," said Paul Davies, an Arizona State University physicist and astrobiologist who was not involved in the paper. "But if it costs very little to go take a look, why not? Even if we don't find E.T., we might find something of interest."
Right now, the closest star to Earth that's not the sun is the Alpha Centauri, which is 4.37 light-years away. However, every so often — about once in every half a million years — a star ventures closer Earth at a distance of just about 1 light-year. This means that over the planet's entire lifetime, hundreds or thousands of star systems have been close enough to Earth to make contact.
Benford proposed looking at co-orbitals using optical and radio telescopes, then pinging these space objects with planetary radar just in case extraterrestrial civilizations are still listening.
