Hubble Images Suggest Rogue Asteroid Smacked Jupiter
Jupiter with inset time series showing asteroid scar fadingThese 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
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"The object that hit Jupiter this time would have been small, dark, and cold—in other words, hard for us to see before the impact, regardless of which wavelength we used for observations," adds Amy Simon-Miller, a co-investigator at NASA's Goddard Space Flight Center in Greenbelt, Md.





The visible spectrum, however, was "nearly identical in this case to what we saw for SL9," says Simon-Miller, who recalculated the SL9 spectrum for this analysis. "This isn't surprising, because most of the debris we're looking at is actually burnt-up atmosphere: hydrogen, hydrocarbons, and soot. It's very black, just like the soot we're familiar with, and has a very flat spectrum."

By analyzing the temperatures and the spread of debris around the impact site, Simon-Miller also determined that much of the debris was located high in Jupiter's stratosphere. "Based on the temperature, we figured out how the wind changed with height," she explains. "And by looking at how the debris was moving, we figured out how high in altitude it must be."






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