Jupiter

The fifth farthest planet from the Sun has been a long focus of study - since Galileo discovered the first moons beyond Earth. Jupiter has twice the size of all the planets in our solar system combined. The stripes and swirls seen on Jupiter are cold, floating in the atmosphere of hydrogen and helium. The great red spot on the gas giant is actually a storm that is bigger than Earth and has been raging for hundreds of years.

Jupiter is surrounded by lots of moons. Jupiter also has very faint rings around it which made of dust and ice.

## Exploration

Nine spacecrafts have studied Jupiter up close. NASA's Juno spacecraft which is currently studying the planet from its orbit. The spacecraft, which arrived at Jupiter's orbit in July 2016, is the first to study the gas giant's many features such as the atmosphere. Scientists and astronomers also use the Hubble Space Telescope and ground-based telescopes to regularly check in on Jupiter.

Pioneer 10 was the first spacecraft to fly by Jupiter. Many other spacecrafts then followed including Pioneer 11, Voyager 1 and Voyager 2. NASA's Galileo mission was the first to enter Jupiter's orbit and to send an atmospheric probe into the stormy clouds for scientists to study. There was also the international Ulysses mission which hurled itself into Jupiter's powerful gravity to pas the northern and southern poles.

Two new spacecrafts are being made to study Jupiter's moons up close. NASA's Europa Clipper and ESA's JUpiter ICy Moons Explorer.

Jupiter holds a unique place in the history of the space exploration. in 1610, Galileo used a new invention called the telescope to look at Jupiter and discovered the first moons beyond Earth. The discovery, however, was incorrect. Ancient belief says that everything, including the Sun and other planets, orbited Earth.

## Size and Distance

Jupiter is eleven times larger than Earth, with a radius of 43,440.7 miles (69,911 kilometres). Jupiter is 5.2 astronomical units away. One astronomical unit (abbreviated as 'AU') is the equal distance from the Sun to Earth.

It takes sunlight 43 minutes to travel to Jupiter.

## Orbit and Rotation

Jupiter has the shortest of days in our solar system, lasting at only 10 hours (the time it takes for Jupiter to make one rotation). For Jupiter to make one complete orbit around the Sun (a year in Jovian time), it would take about 12 Earth years (4,333 Earth days).

Jupiter's equator is tilted at only 3 degrees. This means Jupiter spins almost upright and does not have seasons like Earth.

## Structure

Jupiter is similarly structured to the Sun - mostly made of hydrogen and helium. Deep in Jupiter's atmosphere, the pressure and temperature increases, compressing the hydrogen gas into a liquid. This gives Jupiter the largest ocean in our solar system - an ocean which is made of hydrogen instead of water. Scientists believe that, at the depths of halfway in the planet's centre, the pressure becomes so strong that electrons are squeezed off the hydrogen atoms, making liquid electrically conduct 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 that if Jupiter could have a central core or solid material inside, even if may be thick or super hot and dense. Jupiter's centre could reach up to 50,000 degrees Celsius because it'a made of iron silicate materials (similar to quartz).

## Formation

Jupiter took shape when the rest of the solar system formed 4.5 billion years ago, when gravity pulled swirling gas and dust into the massive gas giant we know today. Jupiter took most of its left over mass to form the Sun which ended up with more than twice of the other bodies in the solar system. As a matter of fact, Jupiter has the same elements as the Sun, but it did not gain the same mass of the Sun and ignite.

4.5 billion years ago, when the solar system settled into its current state, Jupiter settled to where it's the fifth planet from the Sun.

## Surface

As Jupiter is a gas giant, it does not have a true surface. The planet is mostly filled with swirling gas and liquids. While a spacecraft would have nowhere to land on Jupiter, it wouldn't be able to fly through unscathed either. The extreme temperature and pressure inside the planet would cause any spacecraft to crush, melt and/or vaporise.

## Atmosphere

Jupiter's appearance is a tapestry of colourful clouds and spots. The gas giant likely has three layers of clouds in its "skies" that, being put together, span to about 44 miles (71 kilometres) wide. The top layer of clouds is probably made of ammonia ice, the second layer could be made of ammonium hydrosulfide crystals and the third layer is most likely made of vapour and ice.

The vivid colours you see in the thick bands across Jupiter may be plumes of sulphur phosphorus containing gases rising from the planet's warmer interior. Jupiter's fast rotation - nearly 10 Earth hours - creates strong jet streams separating its clouds dark belts and bright zones across long stretches.

With no solid surface on the gas giant, Jupiter's red spots could last for many years. Jupiter is swarmed by dozens of prevailing wind, which could reach up to 335 miles per hour (539 kilometres per hour) at the equator. The Great Red Spot, a swirling oval of clouds twice as wide as Earth, has been studied for more than 300 years. More recently, three oval of clouds formed to create the Little Red Spot, about half as small as its cousin.

## Magnetosphere

The Jovian magnetosphere is influenced by Jupiter's powerful magnetic field. It balloons 600,000 to 2 million miles (1 to 3 million kilometres) towards the Sun (seven to twenty one times the diameter of Jupiter itself) and creates a tadpole-shaped tail extending more than 600 million miles (1 billion kilometres) behind Jupiter, as far as Saturn's orbit. Jupiter's magnetic field is 16 to 54 powerful more times than Earth. It rotates with the gas giant and sweeps up particles that have electrical charge. Near Jupiter, the magnetic field traps swarms of these charged paritcles and accelerates them to very high energy, creating intense radiation that bombards the innermost moons and can damage spacecrafts.

Jupiter's magnetic field also causes some of the solar systems most spectacular aurorae ever at its poles.

## Rings

Discovered in 1979 by NASA's Voyager 1 spacecraft, Jupiter's rings were a surprise to many, as its composed of small, dark particles that are difficult to see when backlit by the Sun. Data from the Galileo spacecraft suggests that Jupiter's ring system may be formed by dust kicked up as interplanetary meteoroids smashed into the gas giant's inner most moons.

## Moons

With many small moons and four large moons, Jupiter has formed a miniature solar system. 53 moons have been confirmed, 26 are waiting confirmation. Moons are named after there discovery.

Jupiter's four largest moons - Io, Europa, Ganymede and Callisto - were first observed by astronomer Galileo Galilei in 1610 using an early development of the telescope. Today, these four moons are known as Galilean satellites, and are some of the most fascinating destinations in our solar system. Ganymede is the largest moon in our solar system (even bigger than Mercury. Callisto's very small craters indicate a very small surface activity. A liquid-water ocean with the right elements may lie beneath the frozen crust of Europa, making a very tempting place to explore.

> See more on Jupiter's Moons

## Human Life

Jupiter's temperatures and storms make human life very unlikely to appear.