In order to find Amalthea, we begin with the search for Jupiter. It moves through the constellation Pisces and does not have a permanent location in it. This planet is different in size and shines brightly, so where Jupiter is located in the sky, you will notice a brighter star against the background of dimmer objects.
Discovery and title
Amalthea is the most mysterious of all the moons of Jupiter.
Amalthea is a satellite discovered in 1892 by Edward Emelson Barnand at the Lick Observatory using a refractor telescope. She became the final companion discovered by visual observation, and not the photographic method, like everyone else. The satellite did not have a name for a long time, as the discoverer simply called it the fifth satellite of Jupiter. And after almost a century, in 1976, he got his name - Amalthea. That was the name of the goat that raised the baby Zeus (in Greek mythology).
Jupiter's moons
Today it is not known for certain how many satellites Jupiter has, but scientists suggest that there are at least a hundred of them. To date, 67 have been recorded, and only 63 objects have been well investigated.
All the
satellites of the planet are divided into three categories "gallium", internal and external, the largest were named after the ancient heroes. Jupiter, as you know, has the largest number of satellites, this explains why there are so many “moons” near it, since it has a powerful gravitational field.
The sizes of the moons of Jupiter are very different. Among them, bodies were found quite small, medium and large. The largest and most famous of them are the four Galilean satellites: Ganymede, Europe, Io and Callisto, discovered by Galileo Galilei in 1610. Gallium satellites surrounded Jupiter after its formation and were formed from dust and gases.
Groups of moons of the planet Jupiter
The outer group consists of small satellites, the diameter of which varies from 1 to 170 km. Their orbits are quite elongated and inclined toward the equator of Jupiter. At the moment, 59 objects of the external group are listed. Satellites that are in close proximity to the planet move in their orbits in the direction of rotation of Jupiter, and most of the distant satellites move in the opposite direction. The largest group of satellites, such as Amalthea, Adrasea, Metis, and Phoebe, belong to the inner group.
physical characteristics
The "Moon" has an irregular shape, it is an elongated bean-shaped body, directed with its sharp end to the planet Jupiter.
Amalthea - the satellite is quite unique, it makes a revolution around its axis and around the gas giant synchronously in 0.498 days. The entire surface of the “Moon” is dotted with craters, some of them are of enormous size, such as Pan and Gaia (today only two sharks and two craters have received names, the rest have remained nameless). Amalthea is a satellite that has its own ring, which is called “spider web” for its fuzzy structure. The formed ring is gradually formed by knocking out particles by meteorites from its surface layer.
The force of gravity on Amalthea is very small, so dust particles and fragments easily leave its surface. The satellite is the fifth in size, second only to the "gallium", the third in remoteness from Jupiter. Its linear dimensions are 250 by 146 and 128 km, respectively. Like many satellites, she is constantly facing the planet on the same side. Amalthea is a satellite that emits more heat than it consumes from the Sun, but this is not a consequence of some processes inside it, but a secondary heating caused by Jupiter radiation and charged particles. Scientists calculated its density, it amounted to 0.9 ± 0.1 g / cm3. Based on the size and mass of Amalthea, on this basis it was concluded that its main composition includes watery ice. Moreover, the ice is not continuous, but with voids that have accumulated in the body under the influence of gravity.
Spectral analysis indicates the existence of sulfur compounds and hydrated various minerals. Scientists suggest that Amalthea is once an asteroid captured or was formed in a farther orbit. During the formation of Jupiter and its satellites, the temperature in this orbit reached 800 ° C, and ice Amalthea simply could not appear there. The existence itself is difficult to explain, the satellite is too large to form from planetary rings. Most likely, Jupiter captured it from the outside. You can observe similar phenomena in our days with comets and asteroids.
Satellite coloring
Amalthea- (satellite of Jupiter) - one of the few of its "moons", but the most mysterious. In addition, its color is more saturated than that of the "red planet" of Mars.
Some scientists believe that the red color is a consequence of settled sulfur, which is erupted into space by the volcanoes of Io (the satellite of Jupiter, on which constant volcanic activity is observed). And others believe that this is the formation of chlorine with magnesium, potassium and sodium, which include an admixture of iron oxides and form a red tint. The satellite is not all red; there are also green spots on it. Some scientists suggest that the reason for this is gaseous chlorine, which fills the voids inside the cosmic body, as a result of being squeezed out onto its surface, it forms green spots.
Research
The first pictures of the “Moon” of Jupiter were taken in 1979 by the Voyager -1 and Voyager-2 aircraft. Using this survey in the infrared spectrum, data were obtained on the temperature regime of the surface.
In 1996-2000, the Galileo apparatus made the best pictures (2.4km / pixel). He, flying past Amalthea, calculated the mass by the magnitude of the deviation in his own motion.
In 2000-2001, the Cassini apparatus specified the orbit of Amalthea. In 2006, the New Horizons apparatus redefined the satellite’s orbit. However, this knowledge is not enough. Scientists are still wondering how many moons Jupiter has. The modern Hubble orbital station continues research in search of new satellites in our solar system. Let's hope that the mystery of Almatei will soon be solved.