Juno delves deep into Jupiter’s Red Spot
NASA’s Juno mission, which was launched on Aug. 5, 2011, has uncovered some interesting data after its first pass over the largest planet in our Solar System – the gas giant Jupiter. This data suggests that the massive, fiery-red and centuries-old hurricane known as the Great Red Spot descends farther below the planet’s cloud tops than was previously believed.
These findings were announced on Monday, Dec. 11, 2017, in New Orleans, Louisiana, at the annual American Geophysical Union.
“One of the most basic questions about Jupiter’s Great Red Spot is: how deep are the roots?” said Scott Bolton, Juno’s principal investigator from the Southwest Research Institute in San Antonio. “Juno data indicate that the Solar System’s most famous storm is almost one-and-a-half Earths wide, and has roots that penetrate about 200 miles (300 kilometers) into the planet’s atmosphere.”
Juno conducted its first pass in July of 2017, the instrument that made this discovery was the spacecraft’s Microwave Radiometer (MWR). The probe has also discovered two, previously uncharted, radiation zones.
“Juno’s Microwave Radiometer has the unique capability to peer deep below Jupiter’s clouds,” said Michael Janssen, Juno co-investigator from NASA’s Jet Propulsion Laboratory in Pasadena, California. “It is proving to be an excellent instrument to help us get to the bottom of what makes the Great Red Spot so great.”
In terms of the Great Red Spot, the size of the storm helps to drive home the immense scale of Jupiter’s weather systems, with aspects of the super-sized hurricane dwarfing aspects of our world.
“Juno found that the Great Red Spot’s roots go 50 to 100 times deeper than Earth’s oceans and are warmer at the base than they are at the top,” said Andy Ingersoll, professor of planetary science at Caltech and a Juno co-investigator via a NASA-issued release. “Winds are associated with differences in temperature, and the warmth of the spot’s base explains the ferocious winds we see at the top of the atmosphere.”
While Jupiter has been studied in varying degrees for hundreds of years, its size, as well as the conditions it creates, continues to astound scientists.
“The closer you get to Jupiter, the weirder it gets,” said Heidi Becker, Juno’s radiation monitoring investigation lead at JPL via a release issued by the agency. “We knew the radiation would probably surprise us, but we didn’t think we’d find a new radiation zone that close to the planet. We only found it because Juno’s unique orbit around Jupiter allows it to get really close to the cloud tops during science collection flybys, and we literally flew through it.”
So far the spacecraft, which has a dry mass of some 3,512 pounds (1,593 kg), has completed some nine passes of Jupiter.
The Juno mission, as all space missions do, began with a launch. This one took place at Cape Canaveral Air Force Station’s Space Launch Complex 41 in Florida atop a United Launch Alliance Atlas V 551 (AV-029) rocket. It arrived in orbit above Jupiter on the fourth of July, 2016. Since that time, it has skimmed close to the massive planet. How close? Juno dipped down to about 2,100 miles (3,400 kilometers) above Jupiter’s cloud tops.
The Great Red Spot is perhaps the best-known feature of Jupiter and measures an astonishing 10,000 miles (16,000 kilometers) wide as of April 3, 2017. That makes the long-lived storm, which has existed for at least 350 years, some 1.3 times as wide as our home world. By comparison, the longest-lived Earth hurricane on record lasted for a mere 31 days.
The Great Red Spot might not be around forever, however. In the 19th Century, the storm was estimated to measure about twice the width of Earth. In its statement about Juno’s recent accomplishments, NASA noted the following about the Spot: Today, measurements by Earth-based telescopes indicate the oval that Juno flew over has diminished in width by one-third and height by one-eighth since Voyager times.
Just above Jupiter’s atmosphere and near the planet’s equator, the spacecraft found a previously undiscovered radiation zone. Energetic hydrogen, oxygen, and sulfur ions travel at nearly the speed of light in this region, which was identified by Juno’s Jupiter Energetic Particle Detector Instrument (JEDI).
The particles that JEDI discovered are thought to come from energetic neutral atoms. These fast-moving ions have no electrical charge and are created in the gas located between Jupiter’s moons Europa and Io. These neutral atoms become ions when their electrons are stripped from them when they interact with Jupiter’s turbulent atmosphere.
These are not the only discoveries that the spacecraft, which has a planned mission life of some seven years, has made in the outer reaches of our Solar System.
Signatures of a high-energy heavy-ion population within the inner edges of Jupiter’s relativistic electron radiation belt have also been found. These were discovered when Juno carried out high-latitude passes in areas that were not explored by other spacecraft that have ventured to the 86,881 miles (139,822 km) wide world.
What type of particles these are and where they originate is unknown, they were discovered by Juno’s Stellar Reference Unit (SRU-1) star camera.
Numerous spacecraft have traveled to and flown past Jupiter. These include Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Galileo, Cassini, New Horizons, and Juno.
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.