Credit: N. Bartmann (ESA/Webb), ESO/M. Kornmesser and S. Brunier, N. Risinger (SkySurvey.org)
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. They used data from the calibration of the MIRI instrument, in which the team serendipitously detected an interloping asteroid. The object is very likely the smallest yet to be found in the solar system’s main asteroid belt.