Skip Navigation: Avoid going through Home page links and jump straight to content

HST Gravity Waves Observations


Andrew Ingersoll, Professor of Planetary Science, Caltech

Ingersoll is a member of a team which will be looking for evidence of waves caused by the impacts in Jupiter's atmosphere. Using the Hubble Space Telescope at visible and near-infrared wavelengths, the team hopes to detect subtle changes in the surface clouds, especially changes creating a circular pattern around the impact point, like ripples in a pond. As a wave passes through a point in the atmosphere, the local pressure will rise and then fall, causing the temperature to cool and then warm very slightly, by about one degree Fahrenheit. In areas where gas is just on the edge of freezing, the passing wave's small pressure change should be enough to cause ice crystals to form. Ammonia droplets are the most likely to freeze out, which would create new cloud patterns of white crystals.

Ingersoll has also worked with Hiroo Kanamori, the Smits Professor of Geophysics and director of Caltech's seismological laboratory, and Tim Dowling at MIT, to model what kinds of waves may jostle Jupiter as a result of this impact. One intriguing idea is that the biggest waves will be confined to a narrow altitude range, where the pressure is about 3 to 5 bars, and where there is a layer of gaseous water encircling the planet. (For comparison, the sea-level air pressure on Earth is about 1 bar, and the pressure at Jupiter's cloud tops is about 0.5 bar.) The temperature and density of this layer should have just the right properties so that if the wave travels too high, it will be refracted, or bent, downward. And if the wave travels too low, it will be refracted upward. The net effect is to create an internal wave channel, which should allow the waves to spread a very long distance horizontally. These long-distance waves would act as a probe of Jupiter's interior, much like seismic waves on Earth, and would provide information about different atmospheric levels that cannot be observed optically. Ingersoll and his colleagues hope to detect the water cloud by these observations.