The moon could crash against the earth

Trabanten: Earth has probably caught a mini moon

Its diameter is only 1.9 to 3.5 meters. And yet 2020 CD3 is something very special: The small object has been able to accompany our earth as a so-called mini moon for three years. This is what astronomers around Kacper Wierzchos from the Catalina Sky Survey announced on the website of the Minor Planet Center. "No relationships were found with a known artificial object," write the scientists, thus ruling out for the time being that it is space junk.

The scientists discovered the mini moon on February 15, 2020. They then used the orbit data to calculate how long the object could orbit the earth. According to the data, the boulder reached the earth's gravitational field in 2017 and was caught by gravity. Since then it has orbited our planet in a wide oval. It is mostly outside of the orbit of the large moon. Since the orbit of the little companion is not stable, it could leave the earth-moon system again by April 2020 and disappear into the vastness of space. At least that is what the astronomer Grigori Fedorets from Queen’s University in Belfast suspects in the "New Scientist".

BIG NEWS (thread 1/3). Earth has a new temporarily captured object / Possible mini-moon called 2020 CD3. On the night of Feb. 15, my Catalina Sky Survey teammate Teddy Pruyne and I found a 20th magnitude object. Here are the discovery images. pic.twitter.com/zLkXyGAkZl

- Kacper Wierzchos (@WierzchosKacper) February 26, 2020

In principle, it is not unusual for the earth to catch other companions. The asteroid 2006 RH120, for example, was in the orbit of the earth from September 2006 to June 2007. And 469219 Kamo’oalewa has been orbiting the earth for 100 years on an orbit far outside the orbit of the moon at a distance of about 12 to 16 million kilometers. It takes 366 days to travel around the world, while 2020 CD3 can do it in 47 days.

Such small objects are, however, notoriously difficult to detect: Due to their small size they hardly reflect any light and thus move their circles relatively hidden.