14 Oct, 1998: Two NASA spacecraft, Galileo
and the Mars Global Surveyor, have captured new images of volcanoes
on other planets. The pictures were released yesterday and
include some
spectacular new views of Olympus Mons, the
largest volcano in the solar system, as well as ultra-hot volcanoes on
Jupiter's moon Io.
The first image (right) taken
from a distance of about 560 miles is a wide-angle view
of the Martian volcano Olympus Mons. It captures the west side of the volcano on a
cool, crisp winter morning. Olympus Mons is by far the tallest
volcano in the solar system, rising higher than three
Mount Everests and spanning the width of the entire Hawaiian island
chain.
Olympus Mons may be the grandest volcano in the solar system, but it
is not the most active. In fact it appears to have been dead for
at least hundreds of millions of years.
The most active volcanoes may be found on Jupiter's intriguing moon Io.
Io's volcanoes almost constantly spew forth sulfurous gasses that
create
a giant ring of plasma around Jupiter. As Io moves
around Jupiter it travels through the plasma torus and gives off
magnetized "Alfven waves", much like the
wake from a boat speeding through water.
These waves carry tremendous power -- about 1012 Watts! --
and cause radio emissions that are so powerful they can be heard
in the loudspeakers of Ham radios on Earth.
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Olympus Mons
Olympus Mons is an old Martian volcano that is
very similar in style to the volcanic island
of Hawaii on the Earth. It towers a breathtaking
25 km above the surrounding plains making it the largest
volcano in the solar system. Olympus Mons has probably been inactive for
at least a few hundreds of millions of years.
More information and images from the JPL
Planetary Photojournal.
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The Hottest Spots in the Solar System
These pictures of Io were taken by the Galileo spacecraft in May when the
moon was in Jupiter's shadow. Bright spots on the shadowed surface
are caused by vents spewing hot lava.
The colors indicate
increasing brightness going from blue to yellow to red. Scientists have analysed these images
and discovered that the hot spot marked Pillan
reached temperatures in excess of 2600 degrees Fahrenheit
and may have reached 3140 deg. Fahrenheit. For comparison, the hottest volcanic
eruptions on Earth today reach temperatures of
2240 degrees Fahrenheit. The hot spots on Io are thought to be the hottest places in the
solar system!
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The left and middle parts of this picture show a "raw" image presented without processing other than color coding and
labeling. Small, bright pixels and clusters of pixels represent radiation interference. The bright vertical lines are column
blemishes in the imaging detector (CCD). An image of Io was acquired through both a 1- micrometer filter (left) and
clear filter on the Galileo solid state imaging camera system. Both images were exposed on the same frame; however,
during the left exposure, the spacecraft platform moved, causing the exposure to slide toward the clear filter position.
The middle view disc combines the two exposures.
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The third view (right) is the processed clear filter data. Diffuse glows, produced by energized particles interacting with
gases, highlight both the rim of Io's disc and active plumes such as Marduk. North is to the top of the picture. The
resolution is 14.6 kilometers (9 miles) per picture element (pixel), but camera motion smeared the hot spots over
about nine pixels. They appear bigger than they really are; modeling indicates the actual hot spots are much smaller
than the pixels. The image was taken on June 28, 1997 at a range of 1,440, 000 kilometers (890,000 miles).
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