Jupiter's new blemish

[moyer777]

http://www.nasa.gov/mission_pages/hubble/science/jupiter-strike.html

This kind of thing just fascinates me.



These NASA Hubble Space Telescope snapshots reveal an impact scar on Jupiter fading from view over several months between July 2009 and November 2009. Credit: NASA, ESA, M. Wong, H. Hammel, I. de Pater, and the Jupiter Impact Team


Without warning, a mystery object struck Jupiter on July 19, 2009, leaving a dark bruise the size of the Pacific Ocean. The spot first caught the eye of an amateur astronomer in Australia, and soon, observatories around the world, including NASA's Hubble Space Telescope, were zeroing in on the unexpected blemish.

Astronomers had witnessed this kind of cosmic event before. Similar scars had been left behind during the course of a week in July 1994, when more than 20 pieces of Comet P/Shoemaker-Levy 9 (SL9) plunged into Jupiter's atmosphere. The 2009 impact occurred during the same week, 15 years later.

Astronomers who compared Hubble images of both collisions say the culprit may have been an asteroid about 1,600 feet (500 meters) wide. The images, therefore, may show for the first time the immediate aftermath of an asteroid, rather than a comet, striking another planet.

The Jupiter bombardments reveal that the solar system is a rambunctious place, where unpredictable events may occur more frequently than first thought. Jupiter impacts were expected to occur every few hundred to few thousand years. Although there are surveys to catalogue asteroids, many small bodies may still go unnoticed and show up anytime to wreak havoc.

"This solitary event caught us by surprise, and we can only see the aftermath of the impact, but fortunately we do have the 1994 Hubble observations that captured the full range of impact phenomena, including the nature of the objects from pre-impact observations" says astronomer Heidi Hammel of the Space Science Institute in Boulder, Colo., leader of the Jupiter impact study.

In 2009 Hammel's team snapped images of the debris field with Hubble's recently installed Wide Field Camera 3 and newly repaired Advanced Camera for Surveys.

The analysis revealed key differences between the two collisions (in 1994 and 2009), providing clues to the 2009 event. Astronomers saw a distinct halo around the 1994 impact sites in Hubble ultraviolet (UV) images, evidence of fine dust arising from a comet-fragment strike. The UV images also showed a strong contrast between impact-generated debris and Jupiter's clouds.

Hubble ultraviolet images of the 2009 impact showed no halo and also revealed that the site's contrast faded rapidly. Both clues suggest a lack of lightweight particles, providing circumstantial evidence for an impact by a solid asteroid rather than a dusty comet.

The elongated shape of the recent impact site also differs from the 1994 strike, indicating that the 2009 object descended from a shallower angle than the SL9 fragments. The 2009 body also came from a different direction than the SL9 pieces.

Team member Agustín Sanchez-Lavéga of the University of the Basque Country in Bilbao, Spain, and colleagues performed an analysis of possible orbits that the 2009 impacting body could have taken to collide with Jupiter. Their work indicates the object probably came from the Hilda family of bodies, a secondary asteroid belt consisting of more than 1,100 asteroids orbiting near Jupiter.

The 2009 strike was equal to a few thousand standard nuclear bombs exploding, comparable to the blasts from the medium-sized fragments of SL9. The largest of those fragments created explosions that were many times more powerful than the world's entire nuclear arsenal blowing up at once.

The recent impact underscores the important work performed by amateur astronomers. "This event beautifully illustrates how amateur and professional astronomers can work together," notes Hammel.

Occasional dark spots have appeared on Jupiter throughout the history of sky watching. Observing records of the planet are filled with references to spots, including "white spots," "peculiar spots," and "well-defined spots." Only a handful may have described possible Jupiter strikes.

In 1686, the Italian astronomer Giovanni Cassini reported a dark spot on Jupiter that was roughly the size of the largest SL9 impact. Nearly 150 years later, in 1834, British astronomer George Airy independently reported a dark feature in Jupiter's southern belts that looked nearly four times as large as shadows cast on the planet by the Galilean moons. Crude telescopes prevented sky watchers from probing the nature of those spots.

The study by Hammel's team appeared in the June 1 issue of The Astrophysical Journal Letters.

For images and more information about Jupiter, visit:
hubblesite.org/news/2010/16
nasa.gov/hubble

[Bryancd]

Very cool. Jupiter is out there playing some awesome defense for planet Earth, blocking lot's of rock which might otherwise find us. A 1600 foot asteroid is a planet killer for us.

[Rico]

Very cool.  I wonder how they can tell that it was an impact and not just some type of distortion or storm in the cloud layer?

[Feathers]

Or an alien attack? ;)

[Bryancd]

Very cool.  I wonder how they can tell that it was an impact and not just some type of distortion or storm in the cloud layer?

They can likely detrmine it's a hole punched down through the clouds. Also the fact that is appears suddenly and then gradually fades. Shoemaker-Levy was an amazing event to watch and those impacts looke just like this. Interesting how you can see that the aseroid came in at an angle by the shape of the impact site. The comet peices came in much more directly and made more round impacts.

[Bromptonboy]

Now that we put the fear of fire in the Moon by crashing objects onto the surface, our bombardment of Jupiter has commenced.  Operation Jovian Storm:  those Jovian B@st@rds will rue the day they turned their so called great red spot on us! 

[Feathers]

It surprises me that it takes as long as it does to fade.

Without knowing anything about the construction of gas giants, however, I guess I have no real right to be surprised.

[Bryancd]

Now that we put the fear of fire in the Moon by crashing objects onto the surface, our bombardment of Jupiter has commenced.  Operation Jovian Storm:  those Jovian B@st@rds will rue the day they turned their so called great red spot on us! 

LOL!!!!!!!

[Bromptonboy]

It surprises me that it takes as long as it does to fade.

Without knowing anything about the construction of gas giants, however, I guess I have no real right to be surprised.

Did any one else read this article about how Jupiter literally lost-is losing a stripe?

http://science.nasa.gov/science-news/science-at-nasa/2010/20may_loststripe/

Before someone else beats me to this observation - can it be attributed to Jovian Global warming (smirk) ..... we all know their taste for size...SUV's & Hummers everywhere..somehow this is George Bush & Gordon Brown's fault...I just know it..   :)

[Blackride]

It surprises me that it takes as long as it does to fade.

Without knowing anything about the construction of gas giants, however, I guess I have no real right to be surprised.

Did any one else read this article about how Jupiter literally lost-is losing a stripe?

http://science.nasa.gov/science-news/science-at-nasa/2010/20may_loststripe/

Before someone else beats me to this observation - can it be attributed to Jovian Global warming (smirk) ..... we all know their taste for size...SUV's & Hummers everywhere..somehow this is George Bush & Gordon Brown's fault...I just know it..   :)

This is amazing to me and there seemed to be a lack of coverage or caring from the media on it...

[beer]

I saw this covered a bit ... A burst of news from various science news sites on twitter, but haven't heard anything since.

I don't know much about the solar system any more, but don't we have one of those rover robot guys landing on one of Jupiter or Saturn's moons in a year or two? The one they believe has water oceans under ice... Europa?

[Bromptonboy]

A rover to Europa!  They are forgetting Dave Bowman's warning:
ALL THESE WORLDS
ARE YOURS EXCEPT
EUROPA
ATTEMPT NO
LANDING THERE
USE THEM TOGETHER
USE THEM IN PEACE

[QuadShot]

Stars...it's full of...stars...

[beer]

A rover to Europa!

I had the right moon but was totally wrong about the exploration. I found the podcast that I had listened to a week or so ago that I had thought mentioned such a rover. (AstronomyCast #174) Not sure how I got mixed up.

BTW, Bromptonboy - off the topic but, I know you like reading Martin and Jordan etc., if you're interested The Functional Nerds podcast just posted an interview with L.E. Modesitt.

[Bryancd]

Saturn will also eventually lose it's rings.