Sunday, February 18, 2018

EUROBEA MONS BY NASA VOYAGER 1 MISSION





NASA VOYAGER I MISSION (1977-2012)
Eurobea Montes (10, 500 m /34, 448 ft -  10, 5 km -  6,5 mi) 
Io (Jupiter's moon)

1.  In Voyager 1 view of Euboea Montes; the main massif is to upper right of center;  the dark oval to its lower left is Creidne Patera. North is at top,   from NASA's image PIA00328, 1 march 1979

 2  In Voyager 1 view of two of Io's ten highest peaks, Euboea Montes, just below upper left, and Haemus Montes, at lower right  © NASA's image PIA00328, 1 march 1979


The mountain 
Eurobea Montes (10, 500 m /34, 448 ft -  10, 5 km -  6,5 mi)  is a mountain on Io, on of the moons of Jupiter. Its coordinates are at 48.89°S 338.77°W.  Euboea Montes is rugby ball shaped (175 km by 240 km), located about 40 kilometers east of Creidne Patera caldera.  There is a curved ridge crest which divides Euboea Montes into two sections: the steep, southern flank with an uneven surface of rounded mounds and the smoother, northern flank sloping about 6° to the northwest. At the base of the northern flank is a thick, ridged deposit with rounded margins.
Schenk and Bulmer used their observations of NASA Voyager 1 images, measurements of heights on the digital elevation map generated from the images, and analogies to Earth structures to characterize Euboea Montes. According to them, the mountain is one block of crustal material, due to its polygonal, relatively intact shape. The block was raised and tilted (by about 6°) by thrust faulting. This uplift led to a massive landslide along the mountain's northern flank.
This scenario is directly tied to the recycling of Io's crust. Older crustal pieces are forced to sink as newer material is thrust above them. This old volcanic crustal material is compressed laterally as it sinks. Schenk and Bulmer argue that this global compression on Io is at least partially relieved by thrust faulting and uplift of large crustal blocks. On Earth, a similar mechanism exists, for example in the Black Hills of Dakota.
Schenk and M. H. Bulmer identify the deposit of a possible landslide off Euboea Montes. The thick deposit at the northern flank is interpreted to be from a landslide, and they further point to the shape of the northern flank as evidence for slope failure. The estimated volume of the debris apron is about 25,000 km3. If this is true, then Euboea Montes has arguably one of the largest debris aprons in the Solar System, of a size similar to those formed by landslides in Valles Marineris, around Olympus Mons on Mars, or submarine landslides on Earth.

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.