Astronomers report that interstellar comet 3I/ATLAS, heading toward the inner solar system, is much larger than previously thought, with a likely mass over 33 billion tons and a nucleus more than 3.1 miles wide.

Observations from the Webb Space Telescope suggest it is mostly carbon dioxide with water ice in its core.

First detected in July by NASA’s ATLAS system in Chile, the comet poses no threat to Earth but will pass near Mars, Venus, and Jupiter.

3I/ATLAS will disappear behind the Sun in September and is expected to reemerge in December, ABC News has reported.

This is only the third interstellar object observed entering the inner solar system, following “Oumuamua” in 2017 and comet 21/Borisov in 2019.