[meteorite-list] New Horizons Images of Jupiter and Its Moons

[Ron Baalke]

http://pluto.jhuapl.edu/gallery/missionPhotos/pages/022807_1.html

[Ganymede Image]

This is New Horizons' best image of Ganymede, Jupiter's largest moon, 
taken with the spacecraft's Long Range Reconnaissance Imager (LORRI) 
camera at 10:01 Universal Time on February 27 from a range of 3.5 
million kilometers (2.2 million miles). The longitude of the disk 
center is 38 degrees West and the image scale is 17 kilometers 
(11 miles) per pixel. Dark patches of ancient terrain are broken 
up by swaths of brighter, younger material, and the entire icy 
surface is peppered by more recent impact craters that have 
splashed fresh, bright ice across the surface.

With a diameter of 5,268 kilometers (3.273 miles), Ganymede is 
the largest satellite in the solar system.

This is one of a handful of Jupiter system images already returned 
by New Horizons during its close approach to Jupiter. Most of 
the data being gathered by the spacecraft are stored onboard and 
will be downlinked to Earth during March and April 2007.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/
Southwest Research Institute 

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http://pluto.jhuapl.edu/gallery/missionPhotos/pages/022807_2.html

[Europa Image]

This image of Jupiter's icy moon Europa, the first Europa image 
returned by New Horizons, was taken with the spacecraft's Long 
Range Reconnaissance Imager (LORRI) camera at 07:19 Universal 
Time on February 27, from a range of 3.1 million kilometers (1.9 
million miles). The longitude of the disk center is 307 degrees 
West and the image scale is 15 kilometers (9 miles) per pixel. 
This is one of a series of images designed to look for landforms 
near Europa's terminator - the line dividing day and night - 
where low Sun angles highlight subtle topographic features.

Europa's fractured icy surface is thought to overlie an ocean 
about 100 kilometers (60 miles) below the surface, and the New 
Horizons team will be analyzing these images for clues about 
the nature of the icy crust and the forces that have deformed it. 
Europa is about the size of Earth's moon, with a diameter of 
3,130 kilometers (1.945 miles).

This is one of a handful of images of the Jupiter system already 
returned by New Horizons during its close approach to Jupiter. 
Most of the data being gathered by the spacecraft are stored 
onboard and will be downlinked to Earth during March and April 2007.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/
Southwest Research Institute 

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[Image]

The Little Red Spot: Closest View Yet

This is a mosaic of three New Horizons images of Jupiter's Little 
Red Spot, taken with the spacecraft's Long Range Reconnaissance 
Imager (LORRI) camera at 17:41 Universal Time on February 26 
from a range of 3.5 million kilometers (2.1 million miles). The 
image scale is 17 kilometers (11 miles) per pixel, and the area 
covered measures 33,000 kilometers (20,000 miles) from top to 
bottom, two and one-half times the diameter of Earth.

The Little Red Spot, a smaller cousin of the famous Great Red 
Spot, formed in the past decade from the merger of three 
smaller Jovian storms, and is now the second-largest storm on 
Jupiter. About a year ago its color, formerly white, changed 
to a reddish shade similar to the Great Red Spot, perhaps 
because it is now powerful enough to dredge up reddish material 
from deeper inside Jupiter. These are the most detailed images 
ever taken of the Little Red Spot since its formation, and will 
be combined with even sharper images taken by New Horizons 10 
hours later to map circulation patterns around and within the 
storm.

LORRI took the images as the Sun was about to set on the Little 
Red Spot. The LORRI camera was designed to look at Pluto, where 
sunlight is much fainter than it is at Jupiter, so the images 
would have been overexposed if LORRI had looked at the storm 
when it was illuminated by the noonday Sun. The dim evening 
illumination helped the LORRI camera obtain well-exposed 
images. The New Horizons team used predictions made by 
amateur astronomers in 2006, based on their observations of 
the motion of the Little Red Spot with backyard telescopes, 
to help them accurately point LORRI at the storm.

These are among a handful of Jupiter system images already 
returned by New Horizons during its close approach to Jupiter. 
Most of the data being gathered by the spacecraft are stored 
onboard and will be downlinked to Earth during March and April 
2007.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/
Southwest Research Institute 

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http://pluto.jhuapl.edu/gallery/missionPhotos/pages/022707_1.html

[Images]

An Eruption on Io

The first images returned to Earth by New Horizons during its 
close encounter with Jupiter feature the Galilean moon Io, 
snapped with the Long Range Reconnaissance Imager (LORRI) at 
0840 UTC on February 26, while the moon was 2.5 million miles 
(4 million kilometers) from the spacecraft.

Io is intensely heated by its tidal interaction with Jupiter 
and is thus extremely volcanically active. That activity is 
evident in these images, which reveal an enormous dust plume, 
more than 150 miles high, erupting from the volcano Tvashtar. 
The plume appears as an umbrella-shaped feature of the edge of 
Io's disk in the 11 o'clock position in the right image, which 
is a long-exposure (20-millisecond) frame designed specifically 
to look for plumes like this. The bright spots at 2 o'clock are 
high mountains catching the setting sun; beyond them the night 
side of Io can be seen, faintly illuminated by light reflected 
from Jupiter itself.

The left image is a shorter exposure -- 3 milliseconds -- 
designed to look at surface features. In this frame, the 
Tvashtar volcano shows as a dark spot, also at 11 o'clock, 
surrounded by a large dark ring, where an area larger than 
Texas has been covered by fallout from the giant eruption.

This is the clearest view yet of a plume from Tvashtar, one of 
Io's most active volcanoes. Ground-based telescopes and the 
Galileo Jupiter orbiter first spotted volcanic heat radiation 
from Tvashtar in November 1999, and the Cassini spacecraft saw a 
large plume when it flew past Jupiter in December 2000. The Keck 
telescope in Hawaii picked up renewed heat radiation from 
Tvashtar in spring 2006, and just two weeks ago the Hubble Space 
Telescope saw the Tvashtar plume in ultraviolet images designed 
to support the New Horizons flyby.

The New Horizons images of the plume -- which show features as 
small as 20 kilometers (12 miles), are 12 times sharper than 
the Hubble images and about three times sharper than the Cassini 
images. "This is the best image of a large volcanic plume on Io 
since the Voyager flybys in 1979," says John Spencer, deputy 
leader of the New Horizons Jupiter Encounter Science Team from 
Southwest Research Institute. "If the Tvashtar plume remains active, 
the images we take later in the encounter should be even better."

Most of those images will be stored onboard the spacecraft for 
downlink to Earth in March and April.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/
Southwest Research Institute