Io, Jupiter's volcanic satellite
Io, as the innermost satellite of Jupiter, has multiple attributes. It is the fourth largest satellite in the solar system, the densest satellite and the driest celestial body. Io is one of the four celestial bodies with volcanic activity in the solar system. It has more than 400 active volcanoes and is the most active celestial body in geological activities.
superorthicon
Discovery and naming:
Like other Galileo satellites, Io was observed by Galileo in June 16 10 with a telescope designed by himself. At that time, due to the low resolution of the telescope, Io and Europa were difficult to distinguish, so the two satellites were recorded as a single light spot. But the next day, they were separated into different celestial bodies for the first time. This observation was first published in his paper Star Messenger 16 10 in March.
16 14 years, German astronomer Simon Marius said in his book Jupiter's World that he discovered these two satellites at the same time. Although Galileo first announced this discovery, Marius's name was finally adopted in the 20th century (at the request of johannes kepler). Before that, Io was called Jupiter I after Galileo.
Galileo's telescope and his handwritten notes explaining the magnification of the lens were exhibited in an exhibition at Franklin College in Philadelphia.
Like other Galileo satellites, Io was named after a lover of Zeus (Greek version of Rome Jupiter). In mythology, she was the priestess of Hera, the goddess of Argos and the ancestor of Heracles. The names of satellites are usually named after mythical people and places according to their characteristics, such as the mythical Vulcan, volcano, sun and lightning. Because all the places in Dante's Hell have volcanic characteristics, the characters and places inside will also be named.
Size, mass and track:
Io's average radius is1821.6 0.5km, and its mass is 8.93x 1022kg, which is 0.286 times that of radius of the earth and 0.0 15 times that of its mass. Its average orbital distance (semi-major axis) around Jupiter is 421700 km (0.002819 au). Its operation has a small eccentricity (0.004 1), which makes the distance between the near intersection point and the far intersection point 420000km(0.002807 AU) and 423400km(0.002830 AU) respectively.
Comparison of the size of Io (lower left), the moon (upper left) and the earth. Source: NASA /JPL/ University of Arizona.
As Galileo's innermost satellite, it is also the fifth satellite besides Jupiter, and Io's orbit lies between Europa and Europa. Like other Galileo satellites and the moon, Io rotates synchronously with period of revolution and almost always faces Jupiter. It takes about 42.5 hours for Io to orbit Jupiter once, and the average orbital vibration with Europa and Ganymede is 2: 1 and 4: 1 respectively. This means that every time it orbits Europa, it orbits Jupiter, and every time it orbits Ganymede, it orbits Jupiter. This * * * vibration helps to maintain the track eccentricity (0.045438+0), thus providing the main heat source for its geological activities.
relevant knowledge
Io, also known as "Io" or "Io", is the closest of Jupiter's four Galileo satellites, with a diameter of 3,642 kilometers, and is the fourth largest satellite in the solar system. The name comes from a lover of Zeus, the king of gods: IO, who was the priestess of Sheila. Iowa has 400 active volcanoes, which is the most active celestial body in the solar system. Extreme geological activities are the result of tidal heating caused by tidal friction caused by Jupiter's traction inside Io.
Author: Today's University
Jie Zhao
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