This year’s Independence Day holiday was a special one for planetary science, as the NASA spacecraft Juno successfully entered the dense atmosphere of our solar system’s giant, Jupiter, yesterday at 11:53 PM, EDT. After 5 years and traveling nearly 550 million miles, Juno reached Jupiter at nearly 130,000 miles per hour, poised to orbit the planet 32 times, gathering unprecedented data on Jupiter’s atmosphere, magnetic, and gravitational fields, all lending clues to how it formed about 4.57 billion years ago.
Scientists think that Jupiter may have been the first planet to form from the swirling disk of gas and dust from which the rest of the solar system formed. Juno’s science will help unravel the detailed composition of Jupiter’s atmosphere which hold clues to its formation history, including how and where it formed relative to Earth and the Sun.
Unlike Earth and the other terrestrial planets, Venus and Mars, Jupiter is a “gas giant,” composed mostly of Hydrogen and Helium, and may have a rocky core. Juno will closely examine the rollicking storms in Jupiter’s clouds, including its mysterious Great Red Spot that has been shrinking over the several centuries since its discovery.
Jupiter’s largest moons, Io, Europa, Ganymede and Callisto, were discovered by Galileo in 1610, and imaged in detail first by the Voyager mission — twin probes launched in 1977 and now heading to interstellar space — followed by the Galileo flyby in 1995.
Juno will study Jupiter’s atmosphere and (possible) core in unprecedented detail, hopefully unraveling many of the mysteries surrounding fundamental processes during solar system formation, including that of planet Earth. As an observational astronomer interested in the earliest chemical pathways of planet formation, I am particularly eager to learn what Juno uncovers in the depths of Jupiter’s primitive, roiling atmosphere.
Here you can watch Juno approach Jupiter and the Galilean moons in this time-lapse capture by one of Juno’s imagers:
The mission will end in 2018 with Juno taking a nosedive into Jupiter’s atmosphere in a planned maneuver of final demise, similar to previous mission terminations.
In the meantime, we will stay tuned for Juno’s exciting new discoveries! You can watch the NASA’s Juno mission trailer for a brief yet informative and entertaining overview of the exciting science to come!