1991 VG is a Near-Earth object discovered by American astronomer James Scotti on 6 November 1991.
Due to its unusual orbit and rapid variation in brightness, there is speculation that the object could be either man-made or an artifact of an extraterrestrial civilization.
There was also speculation that the object could be a rocket body from a satellite launched in the early 1970s.
However records have been discovered of sightings of the object before the start of the space age, ruling this explanation out.
NASA still has the object listed as “unknown”
A second object discovered
Another recently discovered object with an orbit that is extremely unusual also remains identified.
Comets and asteroids that cross the Earth’s orbit normally have eccentric orbits. The new object does not, it, and 1991 VG, have a similar orbit to that of the Earth.
When it was discovered, astronomers thought it must be a spacecraft that had escaped the Earth’s gravity.
1999 CG9, is considerably brighter than 1991 VG, indicating that it is much larger.
Brian Marsden of Harvard-Smithsonian estimates it to be between 30 and 50 metres across, making it too big to be the final stage of a rocket.