Late on the night of July 4th, NASA team members spent a suspenseful 35 minutes watching as the spacecraft Juno attempted to enter the region around the gas giant planet Jupiter, using a risky maneuver known as an orbital insertion. The main goal of this mission is to learn more about the origin and evolution of Jupiter, which will ultimately improve our understanding of how our entire solar system came to be.

What is so risky about Juno’s orbital insertion maneuver? How close will the spacecraft get to the gas giant, and what does it hope to learn? Here are five quick facts summarizing the excitement around the Juno mission.

1. Juno will get closer to Jupiter than any previous spacecraft ever has

Jupiter is surrounded by an intense band of highly energetic charged particles known as a "radiation belt." A planet’s magnetic field offers protection against such particles, but will also cause them to be trapped along the magnetic field lines in toroid, or donut-shaped, belts.

Mercury, Jupiter, Saturn, Uranus, and even Earth are known to have radiation belts. Venus and Mars, however, do not have significant magnetic fields, and so do not have the ability to trap particles. Jupiter has the strongest magnetic field in the solar system, at nearly 20,000 times stronger than that of the Earth.


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