The Pan-STARRS1 survey telescope on Maui has discovered an object that is headed for Earth’s orbit. This isn’t out of the ordinary except that this object is apparently not an asteroid. In fact, it may even be man-made. After studying the new object scientists concluded that it’s not dense enough to be a solid object. Which means it is probably hollow. This has led to the theory that this object might be the Centaur upper stage rocket booster that helped NASA’s Surveyor 2 reach the Moon in 1966.
Earlier this year in September the mysterious object was discovered and named 2020 SO. As astronomers continued to observe the object, they noticed that the Sun’s radiation was changing the object’s trajectory. This means that the object is most likely not an asteroid as radiation from the Sun would have a hard time pushing a solid object of this size. However, if the object were hollow or if it just has a low density then the effect of the radiation would be explained.
“Solar radiation pressure is a non-gravitational force that is caused by light photons emitted by the Sun hitting a natural or artificial object,” said Davide Farnocchia, a navigation engineer at JPL, who analyzed 2020 SO’s trajectory for CNEOS. “The resulting acceleration on the object depends on the so-called area-to-mass ratio, which is greater for small and light, low-density objects.”
If 2020 SO is not an asteroid then what could it be? Well CNEOS Director Paul Chodas looked at the speed and trajectory of the object and turned back the clock to see where the object came from. As it turns out one of the possibilities is that it came close to Earth in 1966. After checking launch dates it seems that everything matches up with the Surveyor 2 mission.
For now, this is still unconfirmed, however, 2020 SO will make two loops around the Earth between now and March when it will leave the influence of Earth’s gravity and continue in its orbit around the sun. During that time it will be the closest on December 1st and astronomers should be able to get a fairly good look.
Never a boring month when it comes to near-Earth objects. Below is a list of objects coming close to our planet in the coming month (2020 SO is of course on the list). For more information please visit the CNEOS website.