Image shows a large impact shown on the bottom left on Jupiter's south polar region captured on July 20, 2009, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii.
Credit: NASA/JPL/Infrared Telescope Facility
SYDNEY: An object has slammed into Jupiter leaving a "black scar" the size of Earth in the atmosphere of the giant gaseous planet. Experts believe the object is likely to have been a comet.
Images taken using an infrared telescope on Mauna Kea, Hawaii, show a dark scar-like patch and a bright shower of debris particles in the planet's upper atmosphere.
Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, ruled out a weather event as the cause of the mark.
Unlike all known weather phenomena
"It was completely unlike any of the weather phenomena that we observe on Jupiter," said Glenn Orton, a NASA planetary scientist. "We knew this was an impact… there's no natural phenomenon that creates a black spot and bright particles like that."
This is the first time an impact has been observed on Jupiter since 1994 when more than 20 fragments of the comet Shoemaker-Levy 9 (SL9) slammed into the planet. "This has all the hallmarks of an impact event, very similar to Shoemaker-Levy 9," said NASA's Leigh Fletcher.
The shape and brightness of the mark will help in determining the energy and origin of the object that impacted Jupiter, said the scientists. They believe it is the result of a single asteroid or comet, rather than a chain of fragments, as in the case of SL9.
"It's early days, but it's probably intermediate between the smallest and largest of the SL9 fragments, produced by something maybe a few hundred metres across," said Fletcher.
"Tremendously exciting"
We've only known of something like this impacting Jupiter twice in recorded astronomy, he said. "So it's tremendously exciting that we're able to observe it from here on Earth."
Australian amateur astronomer Anthony Wesley, based in Murrumbateman, NSW, first discovered the evidence of the impact on Sunday.
"What I saw… looking at my telescope was a black mark, the size of the Earth, down near Jupiter's south pole. The mark wasn't there when I took photos of that same region two days before." he told Cosmos Online.
"It took me about fifteen minutes looking at the image on my computer to realise I was looking at the after effects of something large having hit Jupiter at that location," said Wesley. "I continued recording information for the next hour and after that I came up to the house and started sending out alerts to everyone I could think of."
By a stroke of luck, Fletcher and colleagues at JPL had already scheduled the NASA Infrared Telescope Facility to observe Jupiter 20 hours after Wesley's initial observations. "With imaging through a whole range of infrared wavelengths we were able to confirm that a huge debris field had appeared in the south pole of Jupiter," he said.
"Events like this give us more information about how the Solar System formed and evolved, so it's very important to watch as closely as possible. The best guess from everyone at the moment is that it was a comet or the remains of a comet," said Wesley.
Atmospheric stirring
Michael Drinkwater, an astronomer from the University of Queensland in Brisbane, Australia, worked at the Anglo-Australian Observatory at the time of the Shoemaker-Levy 9 comet impact, 15 years ago.
He said the real significance of this new event is the observations that researchers have been able to make. "An event like this lifts gases from lower in the atmosphere up to where we can measure them. They will be able to use it to study the layers of the atmosphere of Jupiter."
"Things like this probably hit planets all the time, particularly Jupiter, because its gravity is so big it attracts more collisions. This event is special because we generally miss them because no one is looking," Drinkwater said. "It shows us that a lot of things are happening in the Solar System that we tend to miss."
More common than thought
Michael Brown, an astronomer from Monash University in Melbourne, Australia, said this shows that events like Shoemaker-Levy 9 are not unusual.
"These events appear to be pretty common for Jupiter. We can probably compare with a model of how frequently planets are supposed to be bombarded with comets and the like and see if the rate at which we are seeing objects collide with Jupiter is consistent with this."
"This is a very significant discovery with lasting impact and it's impressive that it was done by an amateur astronomer. However, the result is only days old. The implications and understanding will not come about for a while yet," Brown added.
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