An asteroid roughly the size of Rome’s Colosseum — between 300 to 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. 

Their project used data from the calibration of the Mid-InfraRed Instrument (MIRI), in which the team serendipitously detected an interloping asteroid. 

The object is likely the smallest observed to date by Webb and may be an example of an object measuring under 0.6 miles (1 kilometer) in length within the main asteroid belt, located between Mars and Jupiter. 

More observations are needed to better characterize this object’s nature and properties.

READ MORE: https://www.nasa.gov/feature/goddard/2023/webb-detects-extremely-small-main-belt-asteroid