20 years ago, comet Shoemaker-Levy 9 made headlines around the world when it crashed into Jupiter. The impacts produced the biggest planetary explosions scientists have ever seen.
Astronomers were able to calculate that Shoemaker-Levy 9 had passed so close to Jupiter two years before impact that the giant planet’s powerful gravity had pulled the comet apart into fragments.
Don’t make the mistake that the word ‘fragment’ here means these were tiny particles. Three of the fragments were 1 km or more across.
This was a science story so big that it made headlines all over the world. The single explosion shown page top released the same amount of energy as a simultaneous detonation of 400 million Hiroshima sized nuclear bombs.
Jupiter’s clouds were left with dark scars where the impacts took place, which lingered for weeks.
You can read more about the impacts on our Gene Shoemaker page.
So, What’s Been Happening Since?
Just last year, the Herschel Space Observatory captured this image, showing water in Jupiter’s stratosphere.
A minimum of 95 percent of this water actually came from Shoemaker-Levy 9 when it vaporized in Jupiter’s atmosphere. The highest water concentrations are in the cyan/white areas of the image. The highest concentrations are in Jupiter’s southern hemisphere, where the comet struck.
Clearly, after 20 years, Jupiter is still feeling the effects of the comet impact!
But Wait, There’s More (Impacts)
Most of the scientists who were involved in the Shoemaker-Levy 9 observations felt they were watching a once-in-a lifetime event. However…
In 2009, astronomy enthusiast Anthony Wesley was imaging Jupiter from his backyard in Murrumbateman, Australia. A dark patch caught his eye, a patch which reminded him of one of the biggest astronomy stories he’d known in his life – the Shoemaker-Levy 9 impacts.
The patch he could see looked very much like the scars he had seen on Jupiter from Shoemaker-Levy 9′s impacts.
Anthony Wesley quickly let the world’s astronomy community know what he had seen.
Telescopes around the world quickly turned to focus once again on Jupiter.
And, sure enough, there it was… a new impact scar.
Experience with the Shoemaker-Levy 9 impacts allowed astronomers to estimate the object that hit Jupiter in 2009 was a few hundred meters across.
So what else does the 2009 impact tell us?
The 2009 collision means that:
Either impacts are much more frequent than astronomers thought – most had thought there wouldn’t be another major impact on Jupiter for hundreds of years…
Or it means that we’ve just been unusually privileged to see to such impact events within the space of 15 years.
Personally, I’m hoping it’s the latter of these two possibilities!