International astronomers detected an asteroid roughly the size of Rome's Colosseum, between 300 and 650 feet in length.

The asteroid roughly the size of Rome’s Colosseum – between 300 and 650 feet (100 to 200 meters) in length – has been detected by an international team of European astronomers using NASA's James Webb Space Telescope.

"We – completely unexpectedly – detected a small asteroid in publicly available MIRI calibration observations," Thomas Müller, an astronomer at the Max Planck Institute for Extraterrestrial Physics in Germany, said in a statement.

In an analysis of this data, the team's results suggest the object measures 100–200 meters, occupies a very low-inclination orbit and was located in the inner main-belt region at the time of the Webb observations.

Ball Aerospace lead optical test engineer Dave Chaney inspects six primary mirror segments, critical elements of NASA's James Webb Space Telescope, prior to cryogenic testing in the X-ray & Cryogenic Facility at NASA's Marshall Space Flight Center in Huntsville, Ala. (Credit: NASA/MSFC/David Higginbotham)

If confirmed as a new asteroid discovery, this detection would have implications for the understanding of the formation and evolution of the solar system.