Astronomers have discovered a small object in space that will pass through a small gap of only 50,000 km from Earth on 1 December 2020. Not only that, but the gravity of our planet will change its trajectory so much that it will become a floating moon of the Earth!
Here’s the real kicker: this object is almost certainly No Asteroids. Instead, astronomers think it is actually a rocket booster spent from a 1966 robotic moon mission!
The object, named 2020 SO, was discovered in September 2020 by the Pan-STARRS telescope, which performs the task of looking at the sky, in part, for Earth objects. It didn’t take long to see that the class was strange … it was in Familiar. Its shape, size, and its geometry are close to the Earth’s orbit.
This would be very unusual for an asteroid, but it is what you expect for a rocket booster or space probe. So astronomers discovered the rear orbit, and found something amazing: in September 1966 it was so close to Earth! If it was an asteroid, meaning it would have passed us by now, but if it was indeed from a space mission, it could have been the launch date.
And, as it happens, there Was A spacecraft was then launched: Surveyor 2, a mission for an investigation on the Moon.
In fact, it gets better. Surveyor 2 was launched on September 20, 1966 using an Atlas-Centaur rocket. The Atlas performed well in the first stage, and the Centaur upper stage then extended the spacecraft toward the moon. However, a midcourse correction made by Surveyor 2 went haywire, causing the spacecraft to drift into a ditch that could not be recovered. It slipped at a speed of about 10,000 kilometers per hour on lunar days. Ouch.
But in that second phase, Centaur boosters kept going. It crossed the Moon and went into orbit around the Sun.
Could 2020 SO be the Centaur Rocket?
is most likely. The brightness of 2020 SO indicates that it is 4-10 meters wide. The size of the centaur is about 3×13 meters, so it fits.
And there is a more subtle reason to think that they are one and the same. Very careful measurement of the object’s orbit shows that it is being greatly affected by the pressure of sunlight. Photos obtained from the Sun hit the object and are reflected changing its speed over time. This force (similar to the YORP effect) gradually changes an object’s orbit, but is more pronounced for less large-scale (hence, usually smaller) objects. A spent rocket booster is a large hollow tube, so this effect must be strong … as found by astronomers.
SO’s orbit is very much like Earth since 2020, when one overtakes the other, it is relatively slow (like two cars on the highway can move faster, but one car seems to Is that the second is passing slower). In November 2020 it was passed into the mountainous region of the Earth, the volume of space around the Earth where the gravity of our planet dominates the Sun. This volume is about 1.5 million kilometers in radius.
Usually an interplanetary object passes correctly, but 2020 SO is moving slowly which is occupied by Earth for a short time. It would take about four months to make a big loop around us, then the moon and Earth’s gravity at its other end would give it enough energy to escape again, which would once become the satellite of the Sun.
When it comes to a close in December, astronomers hope to be able to observe it, which will tell us its composition. He can take up the matter of its origin.
I note that it has been done before, with the old space hardware being mistaken for Earth and an asteroid initially. In addition, we also have temporary moons! The asteroid 2020 CD3 orbited the Earth for a few years before being revisited in 2020. Another asteroid, 2006RH120, orbited the Earth for a few months in 2006/7. Yet another object (just 20 cm) actually burned into our atmosphere as a meteor after orbiting the Earth for a while.
These are nicknames minimoons, Although the technical term is Temporarily captured objects, Or TCOs. This is an excerpt from orbital mechanics, but an interesting one. I wonder if, if not in the not too distant future, we might send one to a space probe, because for us their slow velocity makes them a juicy target.
… but what would be a surprise if, like the 2020 SO, it turned into the spent upper stage of an old space mission instead of an asteroid! that would be cool. Scientists may be disappointed, but I’m sure there will be very interesting engineering data – for example, erosion from the solar wind, or impact by micrometers – that rocket scientists drooling to get their hands on. And if it’s an asteroid, well, it wouldn’t be so bad either.
so stay tuned. In a few weeks we should know a lot about this esoteric visitor from space.