Look up to the night sky. What do you see? The moon, probably. No stars, most likely, thanks to pollution. But if you look closely enough, you might just spot a new entrant in our orbital family – Earth’s new moon, which has been named 2020 CD3.
Okay, don’t strain your eyes. You wouldn’t be able to spot CD3 anyway – it’s the size of a car (and no, it's not Elon Musk's car). But it’s definitely out there: a mini-moon that's been circling around our blue planet for the past many months – possibly even three years!
How Did it Come to This?
Astronomers suspect CD3 originated in the asteroid belt between Mars and Jupiter, breaking away and passively moving across space before being caught by Earth’s gravity.
Since then, it’s been circling our world, albeit not in neat loops like the Moon (here’s what its orbit looks like - it's like the Moon, but drunk).
Also, CD3 is like a moon because it’s circling a planet like a satellite would. But it’s not the Moon because it doesn’t do Moon-like things, like light up the night sky or play with the ocean tides.
CD3 is actually the second mini-moon asteroid-like body astronomers have captured. The first, 2006 RH120, hung around between September 2006 and June 2007 – before it escaped.
Yes, escaped. Mini-moons don’t loiter around forever. They are “temporarily captured objects”. Pretty soon, CD3 too will break free from Earth’s gravitational pull and fly back into the emptiness of space.
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