Comet 3I/Atlas originates from outside the Solar System.
Why it is true
Comet 3I/Atlas, discovered on 1 July 2025, is the third known interstellar object to cross the Solar System. Its chemical characteristics, with a higher proportion of carbon dioxide relative to water, suggest it formed in a planetary system older than ours.
Source: NASA
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.
Related facts
Comet 2I/Borisov came from outside the Solar System and brought clues about the formation of other worlds.
The interstellar comet 3I/Atlas releases more than five tonnes of water vapour per second.
Halley's comet only passes near Earth every 76 years.
A solar flare equals a billion hydrogen bombs.
