NASA VOYAGER I MISSION (1977-2012)
Boösaule Montes (17, 500 m or 17, 5 km - 57, 400 ft or 10, 9 miles)
Io (Jupiter's moon) - Solar system
as imaged by Voyager I Mission in March 1979
© NASA / Jet Propulsion Lab / USGS
NASA comment for images
Image 1 : " The eruption of Pele on Jupiter's moon Io. The volcanic plume rises 300 kilometers above the surface in an umbrella-like shape. The plume fallout covers an area the size of Alaska. The vent is a dark spot just north of the triangular-shaped plateau (right center). To the left, the surface is covered by colorful lava flows rich in sulfur. "
Image 2 : detail from image 1: Boösaule Montes on the left side of image
The mountain
Boösaule Montes (17, 500 m or 17, 5 km - 57, 4147 ft or 10, 9 miles) is the highest mountain of Jupiter's moon Io, and one of the tallest mountains in the Solar System. It is located in the north-west from the volcano Pele ( on right in the first image), in the mountain range Boösaule.The highest (southern) peak of the Boösaule Montes, which is the highest peak on Io, as imaged by Voyager 1. North is to the upper left. This image was created from PIA00323 by cropping and sharpening. NASA's description of the uncropped image is as follows:
The official name of the mountain range was given in honor of the cave in Egypt where Io gave birth to Epaphus, and approved by the IAU in 1985.
Mountains are widely distributed across the surface of Io, the innermost large moon of Jupiter. There are about 115 named mountains; the average length is 157 km (98 mi) and the average height is 6,300 m (20,700 ft). The longest is 570 km (350 mi), and the highest is Boцsaule Montes, at 17,500 metres (57,400 ft), taller than any mountain on Earth. Ionian mountains often appear as large, isolated structures; no global tectonic pattern is evident, unlike on Earth, where plate tectonics is dominant.
Io is exceptional for the strong tidal heating it undergoes, caused by the eccentricity of its orbit (which results from its resonance with Europa and Ganymede) in conjunction with the proximity and great mass of Jupiter. This leads to widespread and intensive volcanism. Most volcanoes on Io have little relief; those that can be considered mountains are generally smaller than the mountains formed by tectonic processes, averaging only 1,000 to 2,000 metres (3,300 to 6,600 ft) in height and 40 to 60 kilometres (25 to 37 mi) in width. Several geodynamic models of Io exist but the tectonic mountain-building process is still obscure and debatable. However, it is thought to be related to stresses caused by the rapid volcanic resurfacing of the body.
To explore the origin of Io's mountains, classification of morphological types and description of morphological features are necessary. Five morphological types of mountains have been identified.
- Mesa: a mountain with flat top and relatively smooth surface. It may be difficult to distinguish mesas from eroded layered plains. Ethiopia Planum is a good example of this morphological type.
1 mountains on Io are classified as mesas.
- Plateau : an elevated plain with a rugged surface. There is no steep or prominent peak on plateau. Iopolis Planum is a good example of this type. About 46% of Ionian mountains belong to this morphological type.
- Ridge: an elevated structure dominated by one or more linear or arcuate rises. 28 mountains on Io (or 24%) have been cataloged into this type.
- Massif: an elevated structure dominated by rugged or complex surface and has one or more peaks. Boösaule Montes and Tohil Mons are good examples.
Sources :
- Io mountains database
- NASA
- Jet Propulsion Laboratory
The imager
The Voyager program is a continuing American scientific program that employs two robotic probes, Voyager 1 and Voyager 2, to study the outer Solar System. They were launched in 1977 to take advantage of a favorable alignment of Jupiter, Saturn, Uranus, and Neptune, and are now exploring the outer boundary of the heliosphere in interstellar space. Although their original mission was to study only the planetary systems of Jupiter and Saturn, Voyager 2 continued on to Uranus and Neptune, and both Voyagers are now tasked with exploring interstellar space. Their mission has been extended three times, and both probes continue to collect and relay useful scientific data. Neither Uranus nor Neptune has been visited by any probe other than Voyager 2.
On August 25, 2012, data from Voyager 1 indicated that it had become the first human-made object to enter interstellar space, traveling "further than anyone, or anything, in history".
As of 2013, Voyager 1 was moving with a velocity of 17 kilometers per second (11 mi/s) relative to the Sun. Voyager 2 is expected to enter interstellar space by 2016, and its plasma spectrometer should provide the first direct measurements of the density and temperature of the interstellar plasma.
Data and photographs collected by the Voyagers' cameras, magnetometers, and other instruments revealed previously unknown details about each of the giant planets and their moons. Close-up images from the spacecraft charted Jupiter’s complex cloud forms, winds, and storm systems and discovered volcanic activity on its moon Io. Saturn’s rings were found to have enigmatic braids, kinks, and spokes and to be accompanied by a myriad of "ringlets." At Uranus Voyager 2 discovered a substantial magnetic field around the planet and 10 additional moons. Its flyby of Neptune uncovered three complete rings and six hitherto unknown moons as well as a planetary magnetic field and complex, widely distributed auroras. Voyager 2 is still the only spacecraft to have visited the ice giants.
The Voyager spacecrafts were built at the Jet Propulsion Laboratory in Southern California, and they were funded by the National Aeronautics and Space Administration (NASA), which also funded their launchings from Cape Canaveral, Florida, their tracking, and everything else concerning the space probes due the radioactive materials on board the spacecraft.
