So making a claim as big as first contact, only to have someone else prove you wrong, can end a career. That means research into anything remotely connected to the idea of alien life gets super, super, cautious. But there are a few odd, unsolved, mysteries in space that researchers will admit might – just might as an outside chance – turn out to be alien in origin. Over the upcoming posts I'll take a look at each of the four most tantalising in turn...
If a possible alien signal is interesting, a possible sighting of an alien space probe is much more so – although I’ll heavily emphasise that I say ‘possible’*, not ‘probable’.
Found in 1991, 1991VG is a 10 meter wide object that follows Earth’s orbit with an eerie – almost artificial – precision. That’s unusual, because sharing an orbit with a large world like Earth isn’t a stable situation: If a natural object did find it’s way onto such a path it wouldn’t stay there for long, as the perturbing effect of Earth’s gravity would throw it off course, or pull it in.
Like this one....
Because of this the initial batch of explanations were centred around the idea that this was some sort of spent rocket stage, or other piece of space junk from Earth. That would also explain why 1991 VG is spinning so rapidly, without showing any signs of breaking up: A rubble pile or space rock would tend to fly apart over millennia, due to centripetal force, but a man made object would be stronger and younger.
Yet matching the object definitively to a mission from Earth has proved difficult, which has left the door open for (as yet un-debunked) speculation that this could be a probe from an alien civilisation, shadowing Earth to observe it.
|If so, then it's a good bet the Empire knows we're here (ahem, sorry, Star Wars reference there...)|
It’s a tantalising possibility, but since then it’s been discovered that small fast spinning asteroids of a definitely natural type do exist. The mystery of it’s perfect Earth-tracking orbit remains however.
It’s discoverer, James Scotti, never raised the idea of an alien space probe. But another researcher, Duncan Steele, noted that the fact that....
“...none of the handful of man-made rocket bodies left in heliocentric orbits during the space age have purely gravitational orbits returning to the Earth [in November of 1991]... ...it might be argued that 1991 VG is a candidate as an alien probe observed in the vicinity of our planet.”
|An artists impression of a probe approaching a star system.|
Steel was just raising the explanation as one that hadn’t been entirely ruled out, so that the scientific community could debunk it.
“I do not think [1991VG] is of extraterrestrial origin,” Steel said in an email. “I do think that we should take seriously the possibility that there are alien artefact's in the solar system, although I very much doubt that there are any, based on what we know so far."
But, so far, no-one has done what Steel hoped and definitively ruled it out.
1991VG will be making a close approach to Earth in 2017, so maybe someone with a powerful telescope will find time to investigate this odd object and identify it once and for all. But failing that a probe, the Near Earth Asteroid Scout, is scheduled to fly there in 2018.