Jupiter Impact Scar is Going, Going, Gone

These NASA Hubble Space Telescope snapshots reveal an impact scar on Jupiter fading from view over several months between July 2009 and November 2009.

The Hubble image of Jupiter's full disk was taken July 23, 2009, revealing an elongated, dark spot at lower, right (inside the rectangular box).

The photograph was taken four days after an amateur astronomer first spotted the scar. The unexpected blemish was created when an unknown object plunged into Jupiter and exploded, scattering debris into the giant planet's cloud tops. The strike was equal to the explosion of a few thousand standard nuclear bombs.

The series of close-up images at right, taken between July 23, 2009 and Nov. 3, 2009, show the impact site rapidly disappearing. Jupiter's winds also are spreading the debris into intricate swirls.

To determine the nature of the culprit that smacked Jupiter, astronomers compared the Hubble images of the 2009 impact site with Hubble photographs of the Comet P/Shoemaker-Levy 9 (SL9) assault on Jupiter in July 1994. In the SL9 collision, more than 20 pieces of a known comet bombarded Jupiter.

Based on that comparison, astronomers say the intruder may have been a rogue asteroid about 1,600 feet (500 meters) wide. The images of the 2009 impact, therefore, may show for the first time the immediate aftermath of an asteroid striking another planet.

One clue pointing to a possible asteroid strike is the swiftly vanishing impact site, which may be due to a lack of lightweight particles in the debris. An asteroid collision may produce fewer fine particles than a strike by a dusty comet.

The impact site's elongated shape also indicates that the object descended from a shallower angle than the SL9 fragments.

The natural-color images are composites made from separate exposures in blue, green, and red light.

About the colours

The image is a composite of separate exposures made by the WFC3 instrument on the Hubble Space Telescope. Three filters were used to sample narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are: Blue: FQ437N (437 nm) Green: Q508N (508nm) Red: FQ634N (634 nm)

About the data

The image was created from Hubble data from proposals 12003 and 12045 : H. Hammel (Space Science Institute, Boulder, Colo.), A. Simon-Miller (NASA Goddard Space Flight Center), J. Clarke (Boston University), I. de Pater (University of California, Berkeley), K. Noll (STScI), G. Orton (Jet Propulsion Laboratory), A. Sanchez-Lavega (University of the Basque Country, Spain), and M. Wong (University of California, Berkley); and proposal 11559 : I. de Pater, P. Marcus, X. Asay-Davis, and M. Wong (University of California, Berkeley), and C. Go (University of San Carlos).