It’s been tough times for Jupiter: The gas giant planet lost a belt in May, and, thanks to the diligence of amateur astronomers, we know that it has been struck by space objects at least three times in the course of a year.
Australian amateur astronomer Anthony Wesley recorded the first impact in July 2009. Well, more accurately, he saw the dark spot left in the Jovian atmosphere by an otherwise unseen collision.
A composite picture of the July 2009 impact, seen as a yellow smudge in mid-infrared light by the Gemini North telescope in Hawaii.
But Wesley didn’t stop there. On June 3, 2010, he and fellow stargazer Christopher Go in the Philippines independently caught footage of an actual flash in Jupiter’s atmosphere.
Weeks later, astronomy hobbyist Masayuki Tachikawa of Kumamoto, Japan, caught yet another Jupiter fireball on tape.
The June 3 impact event sparked several attempts by larger telescopes to look for traces of the collision, like the dark spot found in 2009. After all, the initial flash was about the size of Earth, so it must have been a whopper of a space rock that smacked into Jupiter, right?
Well, as early as June 17 pictures from the Hubble Space Telescope were showing squat, and astronomers started downsizing their estimates for the size of the impactor.
Now, newly released pictures from both Gemini telescopes—twin observatories in Chile and Hawaii—have probed the crime scene even further.
A near-infrared picture of Jupiter taken by the Gemini North telescope, next to a visible-light Hubble shot. The map-projected version shows the impact site inside a yellow circle.
The Hawaiian telescope looked in what’s called near-infrared light, a region of the spectrum that would highlight bits of debris too small to be seen in optical wavelengths.
The Chilean instrument, meanwhile, used its mid-infrared eye to scan for impact-induced heating and chemical reactions in the Jovian atmosphere.
And the mid-infrared version from Gemini South, also with a companion Hubble frame.
Nope. Nada. Zip.
But in the world of science, even no result can be a result.
Based on the size and timing of the flash versus the lack of any persistent blemishes, the Gemini team estimates that the object that hit on June 3 was a mere 26 to 42 feet (8 to 13 meters) across with a mass between 550 and 2,200 tons (500 and 2,000 metric tons).
For comparison, the scientists note that ten meters is the approximate height of a three-story building, while a thousand metric tons is about the same mass as 150 school buses.
Several objects in this size range probably impact Jupiter each year and quickly disintegrate in the planet’s atmosphere, the team says. We’re simply not watching often enough to see the flashes.
“It is interesting to note that whereas Earth gets smacked by a 10-meter-sized object about every 10 years on average, it looks as though Jupiter gets hit with the same-sized object a few times each month,” Don Yeomans, manager of NASA’s Near-Earth Object Program, said in a press statement.
“The Jupiter impact rate is still being refined, and studies like this one help to do just that.”