How long does it take Europa and Titan to travel from Earth to these planets?

It takes about 6-8 hours (although it varies according to the plane)

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(reference books)

After 6 years, 8 months and 3.5 billion kilometers of long space travel, the Cassini space probe successfully entered the orbit around Saturn as planned on July 0, 2004 12: 02, Beijing time, and began a four-year scientific investigation of Saturn's atmosphere, rings and satellites.

Jupiter is the planet with the largest number of natural satellites discovered so far, and 68 satellites have been discovered. Jupiter's motion gradually slows down. The same tidal force also changed the orbits of satellites, making them gradually move away from Jupiter. Io, Europa and Ganymede are affected by tidal force, so the dynamic relationship of revolution is fixed at 1: 2: 4, which changes with each other. Callisto is also a part of it. In the next few hundred million years, Callisto will also be locked, with a running cycle twice that of Callisto and eight times that of Io. Jupiter's moons are named after the people Zeus came into contact with in his life (mostly his lovers).

Io, Europa, Ganymede and Callisto were discovered by Galileo in 16 10. They are called Galileo satellites. Barnard discovered Ganymede with a telescope in 1892. Other satellites were discovered by photography after 1904. Voyager discovered Io XIV in 1979, and Io XV and Io XVI in 1980. Except for the four Galileo satellites, most of the other satellites are big stones with a radius of several kilometers to 20 kilometers. Ganymede is larger with a radius of 263 1 km.

Io can be divided into three groups: the closest group to Jupiter-Europa XXVI, Callisto XIV, Callisto XV and four Galileo satellites, whose orbital eccentricity is less than 0.0 1, belongs to conventional satellites; The rest are irregular satellites. A group of satellites slightly away from Jupiter-Ganymede, Callisto, Callisto and Callisto-have an eccentric distance of 0. 1 1-0.2 1, which is anterograde. The groups farthest from Jupiter-Ananke, Io XI, Io and Europa-are retrograde with an eccentricity of 0. 17-0.38.

The orbits of Jupiter's four Galileo satellites and Callisto are almost all on Jupiter's equatorial plane.

Europa

Europa (Phoenician princess Europa, daughter of King agenor, one of Zeus' lovers) is slightly smaller than the moon, but its density is similar to that of the moon. Its surface is very smooth and covered with a lot of ice. It looks like a big sphere made of ice cream and cream chocolate. Its diameter is 3 138 km, so it looks very bright from a telescope. Another feature of Europa is that the ice is covered with many criss-crossing and cobweb-like light and dark stripes, which are probably cracks in the ice. Europa is covered with a layer of ice with a thickness of 50 kilometers, and there is a layer of ocean with a thickness of 97 kilometers under the ice. Perhaps this is why Europa's surface is so smooth and its albedo is so high. Europa is the satellite with the largest water storage capacity in the solar system, and it is likely to have life.

Europa

Himalia is the natural satellite of Jupiter. 1904, Charles Tommy Tam Palin discovered it at the lick observatory. 1975, which was named Himalia by the International Astronomical Association. In Greek mythology, Himalaya is a fairy. She and Zeus have three sons.

On the day of 65438+February 19, 2000, the Cassini spacecraft took photos of Europa on its way to Saturn. The definition of this photo is very low, so it doesn't show any details about the surface of Europa.

Europa is the largest member of Europa satellite group. This group of satellites includes five satellites orbiting Jupiter. Their distance from Jupiter ranges from 1 1 to130,000 km. Their axes of rotation are all inclined by about 27.5 degrees.

Europa is extremely cold, and the temperature is about-178 degrees.

Europa's atmosphere and rock mass are rich in carbon compounds, so it is very likely to breed life, but it does not contain oxygen.