Asteroids and Comets

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Asteroids and Comets

• Debris of the solar system
• (plus Titan from Cassini-Huygens and pictures
  from Deep Impact)

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Mars an active surface, which has erased many
old impact craters
Impact craters
Volcano
Rift valley
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Europa a very young, icy surface which has
erased (almost) all impact craters
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Ganymede evidence for recent impacts
Jupiters satellite Ganymede is peppered with
bright splashes, where impacts have revealed the
clean, icy surface beneath. The surface tarnishes
with time, partly as a result of the solar wind,
so the impacts must be recent.
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Some of the culprits a selection of small
asteroids
Note the irregular shape and the fact that they
are themselves covered in small craters.
Impactors come in all sizes.
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Various views of asteroid Ida
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Asteroid Mathilde, from NEAR evidence of
fragmentation?
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Montage of views of Eros as NEAR probe approached
it
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Close-ups of Eros from various angles
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Close-ups of the surface of Eros
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NEAR starts its descent to the surface of Eros
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NEAR approaches the surface of Eros
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Contact! in the middle of reading out a frame
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Callisto evidence for a LARGE impact! Note the
circular shock rings around the impact point.
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Montage of images of Comet Borelly, taken by the
space probe Deep Space 1 in September 2001
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Comet Halley nucleus from Giotto spacecraft
Multiple nuclei of comet Shoemaker-Levy 9 on a
collision course with Jupiter (HST picture)
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Close-up view soon after first impact
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Montage of infrared pictures of Jupiter after SL9
impact the effects can still be seen two months
later
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On a smaller scale the effect of impacts of
very small particles aurorae on Jupiter caused
by charged particles from the solar wind or from
Io leaking into the upper atmosphere
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A similar aurora on Saturn, taken by Cassini
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Titans surface from Cassini, taken through a
narrow-band far-red filter
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A radar image of an impact crater on Titan
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The first colour image of the surface of Titan
small boulders, made of ice
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The Deep Impact mission - pre-impact images
Above a jet seen by Hubble about 3 weeks before
impact Right the nucleus from the approaching
spacecraft
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The Deep Impact probe approaches Comet Tempel
1 Left 6 minutes before impact Below 90
seconds, 60 seconds and 20 seconds before impact
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Impact!
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Hubble observes the impact before and after
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Development of the ejecta, as seen by the flyby
spacecraft