Io is a moon of Jupiter and is volcanically active how is this possible?
With over 400 active volcanoes, Io is the most geologically active object in the Solar System.[5][6] This extreme geologic activity is the result of tidal heating from friction generated within Io's interior by Jupiter's varying pull. Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as 500 km (310 mi). Io's surface is also dotted with more than 100 mountains that have been uplifted by extensive compression at the base of the moon's silicate crust. Some of these peaks are taller than Earth's Mount Everest.[7] Unlike most satellites in the outer Solar System (which have a thick coating of ice), Io is primarily composed of silicate rock surrounding a molten iron or iron sulfide core. Most of Io's surface is characterized by extensive plains coated with sulfur and sulfur dioxide frost.
There are 69 known moons of Jupiter.The largest and most popular are the Galilean moons Ganymede, Callisto,Io and Europa.WIKIPEDIA ,2018GOOGLE ,2018
Why are Ganymede and Callisto geologically dead while the other two Galilean moons of Jupiter are active?
Jupiter actually has some 40+ moons, the four moons you refer to also are called the Galilean moons, as medieval astronomer Galileo Galilei, the most famous Italian in history I know of, discovered them, and deduced the laws of planetary motion from their movements. And that's why Io and Europa, the two biggest moons of Jupiter, are geologically active: Jupiter is a monster, it assembles the biggest amount of mass, and thus gravity, within our solar system, and some astronomers even say, a little bit more mass, and Jupiter might have turned into a second sun. (While the "little bit", when I hear astronomers say that, doesn't mean a spoonful or so; they're talking about the masses of earth-like planets.) The reason why Io and Europa are active is that in fact they are small planets with a crust and something underneath we don't know yet. No human made probe ever landed on one of them. We only have pictures of the surface, and we know that they are within the gravitational field of Jupiter, and there might be something to be discovered about them and the gravitational field of Jupiter; it's a vague idea, but there is an idea that, as our earth's moon is responsible for the tides, life on earth as we know it could only have developed because we have a large enough moon, so there's the idea that life could develop on a big moon if there is a large enough planet. Let us finance a mission, two euros each, that should suffice to send a probe there, and then we'll know.
Astronomy- Galilean moons?
the place do you place the Moon? all of us be attentive to for particular that it did no longer style from a similar technique that formed the Earth. It replaced into probable formed from the debris of a collision between Earth (nevertheless right here) and a few smaller merchandise (called Theia via some people). If Theia nevertheless existed, it may of course be called a captured merchandise. even with the shown fact that the unique Theia (or what's left of it) is in all hazard embedded very deep in Earth's mantle, on a similar time as the debris (mix of Earth's crust and Theia's mantle) is what now varieties the Moon. Is the Moon a "captured merchandise"? --- Triton is the main probable no longer in basic terms while you evaluate that's great and retrograde. this is the main probable through fact there is a few evidence that its mantle (made up of water and different "melted ices") replaced into heated to 2 hundred C via the capability of tidal braking, as its orbit replaced into circularized. Triton is plenty a Kuyper Belt merchandise (via its composition) that it of course did no longer style around Neptune. you may ought to discover yet another merchandise it quite is likewise "of course no longer formed around its planet", Jupiter has a great number of smaller stuff in its outer satellites (and a few of it in retrograde orbits) that a lot of them are patently captured asteroids. much extra obvious than Triton. yet they do no longer seem to be on your record. --- The question's wording is hard through fact there is not any objective thank you to degree "likeliness of having been captures" to the component the place you've got a non-subjective record.
While Galileo Galilei, astronomer, physicist, engineer, philosopher, and mathematician, did not invented the telescope (it is unknown who did, he only heard about it) but he used it to observe the celestial objects.He confirmed the phases of Venus, observed Saturn's rings (though he could not see them well enough to discern their true nature, only in 1655, Christiaan Huygens described them as a disk surrounding the planet) and the analysis of sunspots. And he discovered the so called Galilean moons, the four largest moons of Jupiter.The Galilean moons - Io, Europa, Ganymede, and Callisto - were first seen by Galileo Galilei in January 1610, and recognized by him as satellites of Jupiter in March 1610. They are the first objects found to orbit another planet. Their names derive from the lovers of Zeus.IO (Jupiter I)With over 400 active volcanoes, Io is the most geologically active object in the Solar System.Europa (Jupiter II)Slightly smaller than Earth's Moon, is the sixth-closest to the planet Jupiter.Ganymede (Jupiter III)Ganymede is the largest and most massive moon of Jupiter and in the Solar System.Callisto (Jupiter IV)It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan.
It is Io, innermost of the four large satellites of Jupiter that are known as the Galilean moons. (Galileo discovered them in 1610).Io’s density is 3,528 grams per cubic centimeter, about 5% greater than the density of Earth’s moon at 3.34 grams per cubic centimeter.With more than 400 active volcanos, Io is the most volcanically active body in the Solar System because of tidal heating caused by the interaction of the gravitational fields of the other three Galilean moon and Jupiter itself on Io’s interior. The volcanos have been belching forth volatile materials for a long time, some percentage of which exceed Io’s escape velocity and are lost to Io forever. Io has little or no water ice, which is a major component of all the other satellites in the outer Solar System and is only 1 gram/cc in density.
Ever since the Voyager 1[1] flyby I have been kind of fond of Io[2]. It’s the innermost moon of the Galilean 4 and I think it has character:I can still remember the surprise as our first views of extraterrestrial volcanism[3] became evident in the data sent back from Voyager:Massive Volcano Erupts on Jupiter's Moon, Io"In this computer-enhanced picture from Voyager 1 taken in 1979, blue plume on the horizon consists of material hurled upward from volcano to more than 150 kilometers (about 90 miles) above Io's blotchy red-orange landscape."Volcanology of Io"The heat source for Io's volcanism comes from tidal heating produced by its forced orbital eccentricity."Public domain images courtesy of NASA.Footnotes[1] Voyager 1[2] Io (moon)[3] List of extraterrestrial volcanoes
Would you say the small moons and planets are more controlled by external events than internal events? Why?
Small moons and planets are almost completely controlled by the gravitation of other objects (the sun, the planets they orbit, other planets). Gravitational forces from other objects are external. The small planets and moons (Io and Europa are exceptions) have no internal activity. Io and Europa are geologically active but simply as a direct result of the gravitational tug-of-war between Jupiter and the other Galilean moons - so again external.
Facts about Moons:1) Mercury (0), Venus (0), Earth (1) and Mars (2) together have total 3 moons. Jupiter (67), Saturn (62), Uranus (27) and Neptune (14) together have 170 moons.2) The first unmanned mission to the Moon happened in 1959. Spacecraft Luna 1 sent by the Soviet Lunar Program.3) Only 12 people have walked on our moon so far (between 1969 - 1972), all American males.4) The next visit to the moon is planned to happen in 2019 by NASA.5) Jupiter’s moon Ganymede is the biggest among all the moons in the solar system. With a diameter of 5,268 km, it is 8% larger than the planet Mercury.6) The smallest is Saturn’s moon Aegaeon. It has a diameter of only 300 meters. Even smaller than Aegaeon is Saturn’s ‘moonlet’ S/2009 S 1, which is around 200 meters in diameter.7) The earliest discovered moon after our moon (prehistoric) was Jupiter’s Europa, discovered by Galileo in 1610. He discovered 3 other Jupiter’s moons Ganymede, Io and Callisto in the same year.8) The most recently discovered moon is also Jupiter’s, Jupiter LIX, discovered on June 5, 2017.