A New Asteroid The Size Of The Colosseum In Rome Has Been Found By The Webb Telescope

A previously unknown asteroid about 300-650 feet/100–200-meters in length has been spotted in data collected by the James Webb Space Telescope (JWST).

About the same size as the Colosseum in Rome, the object—which currently has no name—is the first sub-kilometr size objects ever found in the Asteroid Belt between Mars and Jupiter.

It’s likely the smallest observed to date by JWST, which spotted the asteroid from a cool 62 million miles/100 million kilometres away.

It was found in data produced while engineers were testing the giant space observatory’s Mid-Infrared Instrument (MIRI) by pointing at at a known asteroid called (10920) 1998 BC1.

While the MIRI data was being analysed this smaller and previously unknown interloper appeared in the same field of view.

“We—completely unexpectedly—detected a small asteroid in publicly available MIRI calibration observations,” said Thomas Müller, an astronomer at the Max Planck Institute for Extraterrestrial Physics in Germany and lead author of a paper published today in Astronomy & Astrophysics. “The measurements are some of the first MIRI measurements targeting the ecliptic plane and our work suggests that many new objects will be detected with this instrument.”

There are about 1.1 million objects in the Asteroid Belt yet astronomers know only about 4,000 of them.

Although small asteroids are predicted to occur in the Asteroid Belt, they’ve not been observed—until now.

This new discovery suggests that many—and perhaps all—observations by MIRI close to the plane of the solar system will include a few asteroids, most of which will be previously unknown to science.

“Our results show that even ‘failed’ Webb observations can be scientifically useful, if you have the right mindset and a little bit of luck,” said Müller. “Our detection lies in the main asteroid belt, but Webb’s incredible sensitivity made it possible.”

MIRI is a camera and a spectrograph that sees light in the mid-infrared region of the electromagnetic spectrum.

The Asteroid Belt is often depicted as a dangerous place where rocky objects are continually smashing into each other. It’s not like that at all. In fact, collisions are extremely rare because the objects are on average about 100,000 miles apart.

What’s more, most of the material in the Asteroid Belt is tied-up in just four large objects—dwarf planets Ceres, Vesta, Pallas and Hygiea. Then there’s the intriguing Psyche asteroid, too, which NASA is planning a mission to observe.

Wishing you clear skies and wide eyes.