After a 2.8 billion-kilometer journey, NASA’s Juno spacecraft will arrive at Jupiter, the king of the Solar System, on July 4, 2016. For millennia, the gas giant has remained a mystery, shrouded in a dense atmosphere of hydrogen and helium. Juno, on the other side, will peer under the planet’s surface and into its core.
Juno will investigate Jupiter’s gravitational and magnetic structures, allowing scientists to test theories about how Jupiter’s atmospheric gases behave under the immense pressures of Jupiter’s interior. Once the current structure of Jupiter is known, it will be possible to understand how, when, and maybe where the planet evolved in the Solar System.
On August 5, 2011, the NASA project was launched into orbit atop an Atlas V rocket from Cape Canaveral, however this alone was inadequate to reach Jupiter. The spacecraft completed a slingshot around the Earth on October 9, 2013, speeding to a final speed of 11km/s owing to our planet’s gravity.
When Juno arrives, it will make 37 extremely elliptical orbits around the Earth. Its path will take it less than 5,000 kilometres above the tallest clouds before swinging out to millions of kilometres and returning in 14 days.
Once its mission is over, the probe will be deorbited in 2018, burning up in Jupiter’s atmosphere to avoid polluting the planet’s moons (about 60 in all), which are thought to be our best shot for finding life beyond our planet.
Complexity under the clouds
Jupiter is a gas giant planet, thus thinking about its surface conditions is pointless: it doesn’t have one. Instead, as you descend, the hydrogen and helium gas that make up the majority of Jupiter’s atmosphere get denser and denser, until the hydrogen becomes a liquid metal.
However, there is still a lot going on in Jupiter’s spinning clouds, which are most likely a combination of water and ammonia. There is also a lot of complexity behind the clouds, as researchers found using a microwave gadget that allows Juno to investigate beneath the clouds.
It turns out, for example, that the east-west winds that are known to blast across Jupiter’s cloud tops aren’t only a high-altitude phenomenon: Winds have the ability to travel thousands of kilometres underground.
Similarly, Jupiter’s famous Great Red Spot — a vortex around the size of Earth that has been swirling for at least two centuries, and maybe much longer: It runs for around 300 kilometres downwards.
Then there’s the case of the vanishing ammonia. “We expected… that once you got below the [clouds], everything would be totally mixed,” says mission commander Scott Bolton, a planetary scientist at the Southwest Research Institute in San Antonio, Texas. After all, Jupiter is a rapidly revolving fluid ball (a day lasts just under 10 hours).
Juno’s microwave data, however, indicate that this jumbled picture is only valid around the equator. It disintegrates while travelling north or south into Jupiter’s midlatitudes, where there isn’t nearly as much ammonia as astronomers thought.
What will Juno be looking into?
Jupiter’s light-colored zones trap rotating vortices hundreds of kilometres wide. These storms can last for a few days, years, or even millennia. Juno will use infrared pictures to see into their depths.
Despite the fact that the majority of Jupiter is hydrogen (90 percent) and helium (10 percent), Juno will analyse the amounts of trace gases such as ammonia and water. Jupiter’s atmosphere has been relatively consistent since its inception, therefore studying it will disclose a lot about the initial Solar System that gave birth to it.
Jupiter’s magnetic field, or magnetosphere, is one of the largest structures in the Solar System, orbiting the gas giant for three million kilometres. It is powered by deep-sea electric currents, but Juno’s magnetic map will disclose whether these currents are created by a solid core or by the motion of highly pressurised’metallic’ hydrogen.
What did we learn from the Juno mission?
NASA’s Juno spacecraft has given its first scientific findings on the amount of water in Jupiter’s atmosphere. According to the Juno data, which were just published in the journal Nature Astronomy, water accounts for around 0.25 percent of the molecules in Jupiter’s atmosphere at the equator.
Jupiter has the most surface area, the largest ocean, the most gravity, and the strongest magnetic field in our solar system. This behemoth knows the answers to the previously mentioned essential questions concerning our own atmosphere, its gaseous composition, magnetism, orbital path, and interaction with the moon.
Indeed, Jupiter data from the JUNO mission will help to improve and broaden our understanding of the Earth’s origins and development.