|Gallery of Jupiter Images from New Horizons||
This dramatic image of Io was taken by the Long Range Reconnaissance Imager (LORRI) on New Horizons at 11:04 Universal Time on February 28, 2007, just about 5 hours after the spacecraft's closest approach to Jupiter. The distance to Io was 2.5 million kilometers (1.5 million miles) and the image is centered at 85 degrees west longitude. At this distance, one LORRI pixel subtends 12 kilometers (7.4 miles) on Io.
This processed image provides the best view yet of the enormous 290-kilometer (180-mile) high plume from the volcano Tvashtar, in the 11 o'clock direction near Io's north pole. The plume was first seen by the Hubble Space Telescope two weeks ago and then by New Horizons on February 26; this image is clearer than the February 26 image because Io was closer to the spacecraft, the plume was more backlit by the Sun, and a longer exposure time (75 milliseconds versus 20 milliseconds) was used. Io's dayside was deliberately overexposed in this picture to image the faint plumes, and the long exposure also provided an excellent view of Io's night side, illuminated by Jupiter. The remarkable filamentary structure in the Tvashtar plume is similar to details glimpsed faintly in 1979 Voyager images of a similar plume produced by Io's volcano Pele. However, no previous image by any spacecraft has shown these mysterious structures so clearly.
The image also shows the much smaller symmetrical fountain of the plume, about 60 kilometers (or 40 miles) high, from the Prometheus volcano in the 9 o'clock direction. The top of a third volcanic plume, from the volcano Masubi, erupts high enough to catch the setting Sun on the night side near the bottom of the image, appearing as an irregular bright patch against Io's Jupiter-lit surface. Several Everest-sized mountains are highlighted by the setting Sun along the terminator, the line between day and night.
This is the last of a handful of LORRI images that New Horizons is sending "home" during its busy close encounter with Jupiter - hundreds of images and other data are being taken and stored onboard. The rest of the images will be returned to Earth over the coming weeks and months as the spacecraft speeds along to Pluto.
Best of Ganymede
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.
Focusing on Europa
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).
Little Red Spot
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.
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.
+ Additional mission photos will be posted at this link as they become available
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Johns Hopkins Applied Physics Lab