Earlier this week, amateur astronomers around the world independently caught a glimpse of something large slamming into Jupiter.
The amount of space debris that must fall regularly onto Jupiter—the largest planet in the solar system—must be astoundingly huge. We can’t see all of these impacts, as the vast majority are very tiny, but every once in a while something big hits this gas giant, creating an impact flash that’s visible to ground observers.
Such an event seems to have happened on September 13 at approximately 10:39 p.m. UTC.
German astronomer Harald Paleske was one of several amateur astronomers who noticed a sudden flareup on the Jovian cloud tops, as Spaceweather reports. The transient flash, spotted along Jupiter’s equatorial regions, “could only be an impact,” he said. Paleske was observing Jupiter’s moon Io casting its shadow onto the gas giant when he made the detection, according to EarthSky.
The fireball lasted for a full two seconds. Spaceweather suspects the offending object was either an asteroid or comet and that it measured around 328 feet (100 meters) in diameter. Paleske ruled out passing objects like planes and satellites as messing with his line of sight, according to Spaceweather.
Amateur astronomer José Luis Pereira of Brazil observed the same thing at the same time. (His video, above, is looped for easy re-watching.) As Sky and Telescope reports, Pereira used specialized astronomy software, called DeTeCt, to spot the fireball. This program, developed by Marc Delcroix, scours through incoming astronomical data, spitting out an alert whenever an anomalous observation, or transient, is detected. The alert in this case assigned a high probability to the flare being caused by a collision. Pereira confirmed the data with Delcroix.
That some kind of object slammed into Jupiter now seems clear, as Delcroix has received similar reports from at least seven astronomers: one from Brazil, two from Germany, three from France, and one from Italy, reports Sky and Telescope.
Large objects are known to slam into Jupiter from time to time, the previous occurrence being in 2019. Famously, cometary fragments from Shoemaker-Levy 9 flew into the gas giant in 1994, creating a temporary scar in the upper atmosphere. At least eight impact flashes have been recorded on Jupiter over the past 27 years, according to Sky and Telescope.
Astronomers are being asked to monitor Jupiter to see if the recent collision also left a mark.