At 11:53 p.m. Eastern time on July 4th the spacecraft sent a signal announcing it had accomplished its five-year journey, traveling 1.7 billion miles from Earth, the New York Times reports. Juno will now spend the next 20 months in various orbits around our solar system’s largest planet—which could be the key to unlocking the origins of our solar system, says the Times:
Jupiter, most likely the first planet formed after the sun, is believed to hold the keys to understanding the origins of our solar system. How much water it contains and the possible presence of a rocky core could reveal where in the solar system Jupiter was created and provide clues to the early days of other planets.
Juno’s instruments are designed to precisely measure the magnetic and gravitational fields of Jupiter and the glow of microwaves emanating from within. That, for instance, will give hints about storm systems like the visible Great Red Spot, which has persisted for centuries, although it has been shrinking.