Jupiter's moon Europa is characterized by a high albedo (0.67) and a fractured icy crust, composed of blocks cracked. These characteristics are the best evidence of tectonic activity both horizontal and vertical and a renewal of its surface.
The surface of the ice crust is torn apart by long and wide dark stripes that indicate intense deformation.
This surface takes the form of an extensive fracture network intermingled, which sometimes accumulate on the outskirts of hydrated magnesium sulfate and sodium (McCord et al., 1998) and / or sulfuric acid (Carlson et al ., 1999).
These data combined with geologic data, in particular, the presence of a magnetic field have led scientists to believe that these traces were probably due to the presence of an underground ocean.
In this false-color image, the brown-red represents areas of non-icy crust, resulting from geological activity. The white areas are the traces of the material ejected during the formation of the impact crater Pwyll.
The icy plains are depicted in this picture, in shades of blue where there are large grains of ice (dark blue) and fine-grained ice (light blue).
We also distinguish long and dark lines of ridges and fractures on the crust, some of which are over 1,850 miles long.
These images were obtained by NASA's Galileo spacecraft in September 1996, December 1996 and February 1997, at a distance of 417.489 miles.
Image: Image Credit: NASA/JPL/University of Arizona
Jupiter, the largest planet in our solar system is surrounded by more than 60 moons. The moons of Jupiter were first discovered in 1610. Galileo Galilei discovered at that time the four largest Jovian satellites system Io, Europa, Ganymede and Callisto.
These Galilean moons called for, were the first to be observed except that of Earth. Today, thanks to space probes, we have a more comprehensive view of the Jovian system. This is the series of Voyager missions which helped lift the veil on the Jovian system by discovering in 1979, Metis, and Thebe Adrastea.
Before the space age, astronomers have discovered Amalthea (1892), Himalia (1904), Elara (1905), Pasiphae (1908), Sinope (1914), and Lysithea Carme (1938), Ananke (1951), Leda (1974 ) and Themisto (1975. Between 1979 and 1999, no new satellite of Jupiter was not discovered and it was not until October 6, 1999, for the Spacewatch program discovers a new moon to Jupiter, Callirrhoe.
Observations in 2000 revealed ten new moons, bringing the number of satellites to 28 after the rediscovery of Themisto, Kalyke, Iocasta, Erinome, Harpalyke, Isonoe, Praxidike, Megaclite, Taygete, Chaldene and S/2000 J 11. The following year, eleven other moons were discovered, bringing the total to 39, Hermippe, Eurydome, Sponde, Kale, Autonoe, Thyone, Pasithee, Euanthe, Orthosie, Europie, Aitne.
In 2002, only one moon, Arche, was discovered.
In 2003 there discovered 23 new satellites, Eukelade, S/2003 J 2, S/2003 J 3, S/2003 J 4, S/2003 J 5, Helice, Aoede, hegemone, S/2003 J 9, S / 2003 J 10, Kallichore, S/2003 J 12, Cyllene, S/2003 J 14 S/2003 J 15 S/2003 J 16 S/2003 J 17 S/2003 J 18 S/2003 J 19 , Carpo, Mneme, Thelxinoe and S/2003 J 23. Most of the 47 satellites discovered after the 2000s are small moons of a few kilometers in diameter, the largest accounting for just 9 km. In 2006, 63 were known moons of Jupiter, the record of the solar system.
|Moons of Jupiter
|Ganymede (Jupiter III)
||1 070 400
|Callisto (Jupiter IV)
||1 882 700
|Io (Jupiter I)
|Europa (Jupiter II)
|Amalthea (Jupiter V)
|Himalia (Jupiter VI)
||11 493 550
|Thebe (Jupiter XIV)
|Elara (Jupiter VII)
||11 676 677
|Pasiphae (Jupiter VIII)
||23 912 238
|Carme (Jupiter XI)
||24 097 020
|Sinope (Jupiter IX)
||23 368 614
|Lysithea (Jupiter X)
||11 665 380
|Ananke (Jupiter XII)
||20 439 111
|Adrastea (Jupiter XV)
|Leda (Jupiter XIII)
||11 098 480
|Callirrhoe (Jupiter XVII)
||24 103 000