NASA JPL Releases Three High Resolution Galileo Images of Jupiter’s Moons Io and Europa

Photo caption: “This picture of Jupiter’s volcanic moon Io combines
hig-resolution black and white images taken by NASAs Galileo spacecraft on
October 10, 1999,
with lower resolution color images taken by Galileo on July 3, 1999
to help scientists better understand the relationships between the
different surface
materials and the underlying geologic structures. For example, there
is red material, which is often associated with areas where lava is
erupting onto the
surface and is thought to be a compound of sulfur, around the margin
of Monan Patera (the elongated caldera just to the lower right of center).
The
broad circle of bright, white material (just to the left of center)
is thought to be sulfur-dioxide which is being deposited from the plume
Amirani.

The lengths of the shadows cast by the mountains make it possible to
estimate the mountains’ heights. The southern mountain on the far right of
the
mosaic is approximately 8 kilometers (26,000 feet) high and the
mountain to the north of it is approximately 4 kilometers (13,000 feet)
high.

North is to the top and the image is centered at 22.8 degrees north
latitude and 109.5 degrees west longitude. The higher resolution images
have a
sharpness of about 500 meters (or yards) per picture element and
they are illuminated from the left. These images were taken at a range of
25,000
kilometers (15,500 miles). The color images are illuminated from
almost directly behind the spacecraft. The color images were taken at a
distance of
about 130,000 kilometers (81,000 miles) and show a resolution of 1.3
kilometers (0.8 miles) per picture element.

Higher resolution versions of
this image are online at NASA’s Planetary Photojournal

Photo caption: “The Zal Patera region of Jupiter’s volcanic moon Io is
shown in this combination of high-resolution black and white images taken
by NASAs Galileo
spacecraft on November 25, 1999 and lower resolution color images
taken by Galileo on July 3, 1999. By combining both types of images, Galileo
scientists can better understand the relationships between the
different surface materials and the underlying geologic structures. For
example, in the
center toward the top of the picture, the edge of the caldera, or
volcanic crater, is marked by the black flows, and it coincides with the
edge of a plateau.
Also, the red material (just above and to the right of the center of
the image) is typically associated with regions where lava is erupting onto
the surface.

Here the red material follows the base of a mountain, which may
indicate that sulfurous gases are escaping along a fault associated with
the formation
of the mountain.

Scientists can use the lengths of the shadows cast to estimate the
height of the mountains. They estimate that the northernmost plateau, which
bounds
the western edge of Zal Patera, rises up to to approximately 2
kilometers (6,600 feet) high. The mountain to the south of the caldera has
peaks up to
approximately 4.6 kilometers (15,000 feet) high, while the small
peak at the bottom of the picture is approximately 4.2 kilometers (14,000
feet) high.

North is to the top of the image, which is centered at 33.7 degrees
north latitude and 81.9 degrees west longitude. The higher resolution
images have a
sharpness of about 260 meters (or yards) per picture element, and
they are illuminated from the left. These images were taken on November 25,
1999
at a range of 26,000 kilometers (16,000 miles). The color images are
illuminated from almost directly behind the Galileo spacecraft. The
resolution of
the color images is 1.3 kilometers (0.8 miles) per picture element.
They were taken on July 3, 1999 at a distance of about 130,000 kilometers
(81,000
miles).

Higher resolution versions of
this image are online at NASA’s Planetary Photojournal

Photo caption: “This 12-frame mosaic provides the highest resolution view
ever obtained of the side of Jupiter’s moon Europa that faces the giant
planet. It was
obtained by the camera onboard NASAs Galileo spacecraft on November
25, 1999 during the spacecraft’s 25th orbit of Jupiter.

The new images have resolutions of about 1 kilometer (0.6 miles) per
picture element. Lower resolution context was provided by images acquired
during earlier Galileo orbits. In the earlier images, the resolution
is 7 and 13 kilometers (4 and 8 miles) per picture element, respectively.

Numerous linear features in the center of the mosaic and toward the
poles may have formed in response to tides strong enough to fracture
Europa’s icy
surface. Some of these features extend for over 1,500 kilometers
(900 miles). Darker regions near the equator on the eastern (right) and
western (left)
limb may be vast areas of chaotic terrain. Bright white spots near
the western limb are the ejecta blankets of young impact craters.

North is to the top of the picture and the sun illuminates the
surface from the left. The image, centered at 0 latitude and 10 longitude,
covers an area
approximately 2,500 by 3,000 kilometers. The finest details that can
discerned in this picture are about 2 kilometers across (about 1,550 by
1,860
miles). The images were taken by Galileo’s camera on November 25,
1999 when the spacecraft was 94,000 kilometers (58,000 miles) from Europa.”

Higher resolution versions of
this image are online at NASA’s Planetary Photojournal