Jupiter has the shortest day in the solar system. One day on Jupiter takes only about 10 hours the time it takes for Jupiter to rotate or spin around once , and Jupiter makes a complete orbit around the Sun a year in Jovian time in about 12 Earth years 4, Earth days.
Its equator is tilted with respect to its orbital path around the Sun by just 3 degrees. This means Jupiter spins nearly upright and does not have seasons as extreme as other planets do. With four large moons and many smaller moons, Jupiter forms a kind of miniature solar system.
Jupiter has 53 confirmed moons and 26 provisional moons awaiting confirmation of discovery. Moons are named after they are confirmed. Jupiter's four largest moons — Io, Europa, Ganymede, and Callisto — were first observed by the astronomer Galileo Galilei in using an early version of the telescope. These four moons are known today as the Galilean satellites, and they're some of the most fascinating destinations in our solar system. Io is the most volcanically active body in the solar system.
Ganymede is the largest moon in the solar system even bigger than the planet Mercury. A liquid-water ocean with the ingredients for life may lie beneath the frozen crust of Europa, making it a tempting place to explore. Discovered in by NASA's Voyager 1 spacecraft, Jupiter's rings were a surprise, as they are composed of small, dark particles and are difficult to see except when backlit by the Sun.
Data from the Galileo spacecraft indicate that Jupiter's ring system may be formed by dust kicked up as interplanetary meteoroids smash into the giant planet's small innermost moons. Jupiter took shape when the rest of the solar system formed about 4. Jupiter took most of the mass left over after the formation of the Sun, ending up with more than twice the combined material of the other bodies in the solar system.
In fact, Jupiter has the same ingredients as a star, but it did not grow massive enough to ignite. About 4 billion years ago, Jupiter settled into its current position in the outer solar system, where it is the fifth planet from the Sun.
The composition of Jupiter is similar to that of the Sun — mostly hydrogen and helium. Deep in the atmosphere, pressure and temperature increase, compressing the hydrogen gas into a liquid. This gives Jupiter the largest ocean in the solar system — an ocean made of hydrogen instead of water. Scientists think that, at depths perhaps halfway to the planet's center, the pressure becomes so great that electrons are squeezed off the hydrogen atoms, making the liquid electrically conducting like metal.
Jupiter's fast rotation is thought to drive electrical currents in this region, generating the planet's powerful magnetic field. It is still unclear if deeper down, Jupiter has a central core of solid material or if it may be a thick, super-hot and dense soup. It could be up to 90, degrees Fahrenheit 50, degrees Celsius down there, made mostly of iron and silicate minerals similar to quartz.
The planet is mostly swirling gases and liquids. The extreme pressures and temperatures deep inside the planet crush, melt, and vaporize spacecraft trying to fly into the planet.
Jupiter's appearance is a tapestry of colorful cloud bands and spots. The gas planet likely has three distinct cloud layers in its "skies" that, taken together, span about 44 miles 71 kilometers. The top cloud is probably made of ammonia ice, while the middle layer is likely made of ammonium hydrosulfide crystals. The innermost layer may be made of water ice and vapor. Its name comes from the Roman god Jupiter. It is high horizontal winds — in excess of kilometers per hour — that cause the zones to spread out planet-wide.
What causes these strong winds remains a topic of research. Replenished by upwelling gas, zonal bands are thought to include relatively opaque clouds of ammonia and water that block light from lower and darker atmospheric levels. One light-colored zone is shown in great detail in the featured vista taken by the robotic Juno spacecraft in Astronomers have no idea how long the spot will last nor why it has lasted so long. The storm is so large that it can be seen from Earth by any medium sized or larger telescope.
A more recent storm has developed on Jupiter that has captured the attention of astronomers. Officially dubbed Oval BA , but commonly referred to as Red Jr, this storm is about half the size of the famous Great Red Spot and almost exactly the same color. Oval BA first appeared in when three smaller spots collided and merged. Scientists theorize that the Great Red Spot may have been created in the same way. Scientists have been using the color of Jupiter to understand the atmospheric workings of the planet.
0コメント