When astronomers on Earth looked into the sky in search of other planets, they anticipated the eventual discovery of solar systems like our own. Imagine their amazement when they first observed planets the size of our own solar system giants (Jupiter, Saturn, Uranus, Neptune) orbiting extremely close to their parent stars. This unexpected discover led planetary scientists to the realization that to understand how these giants function, we must first gain a better understanding of Jupiter’s role in the formation of our own solar system.
To date, Jupiter has had a number of spacecraft fly-bys including Pioneer 10 and 11, Voyager 1 and 2, Ulysses and Cassini, and one orbital mission, Galileo. Galileo was launched in 1989 and after a 6 year journey to Jupiter, spent 8 years studying the planet and its many moons. Galileo returned data from Jupiter that included information about the composition of the upper layer of the giant planet's atmosphere and a partial map of its magnetosphere. This data was collected from both an on-board instrument and from a descent probe.
Although Galileo returned a great deal of new information, it also raised many additional, crucial questions that the Juno science team seeks to answer, including:
- How did the giant planets form?
- Does Jupiter have a rock-ice core, and if so how large is it?
- How different is the composition of Jupiter from the original solar nebula, and if it's different, what is the cause?
- How deep into the atmosphere do the Great Red Spot and other atmospheric features reach?
- How does the dynamo on Jupiter work?
The Juno mission answers these questions and more !!
