A near-Earth asteroid passing us in December may actually be an old Moon rocket - SYFY WIRE

Astronomers have discovered a small object in space that will pass by Earth on 1 December 2020 by the small margin of just 50,000 km.

Instead, astronomers think it's actually a spent rocket booster from a robotic Moon mission launched in 1966!

[UPDATE (2 December 2020): After its close pass on 1 December, astronomers have confirmed that 2020 SO is indeed a Centaur upper stage rocket.

Using NASA's Infrared Telescope Facility, they observed both 2020 SO and a known Centaur rocket in Earth orbit for comparison.

The two spectra matched well enough for them to conclude that 2020 SO is not a natural asteroid but instead the rocket that helped launch Surveyor 2 to the Moon (with unfortunate results; see the text below).

That would be very unusual for an asteroid, but that's just what you expect for a rocket booster or space probe.

A Centaur upper stage like the one that boosted Surveyor 2 to the Moon.

The object 2020 SO may very well be a spent Centaur booster.

The Atlas first stage performed well, and the Centaur upper stage then boosted the spacecraft toward the Moon.

But that second stage, the Centaur booster, kept going.

Could 2020 SO be that Centaur rocket.

In November 2020 it passed into what's called Earth's Hill sphere, the volume of space around Earth where our planet's gravity dominates over the Sun.

Normally an interplanetary object would pass right through, but 2020 SO is moving slowly enough to be captured by Earth...

but what a surprise would it be if, like 2020 SO, it turned out to be the spent upper stage of an old space mission instead of an asteroid.