Space News & Blog Articles

Jupiter is a big planet, but it’s still a planet. That means it doesn’t heat itself through fancy mechanisms like nuclear fusion. Its interior is heated through its own weight, squeezing the interior through hydrostatic equilibrium, and its surface is heated mostly by the Sun. Since Jupiter only gets about 4% of the light per square meter that Earth gets, you’d expect its upper atmosphere to be pretty cold. Traditional models estimate it should be about -70 degrees Celsius. But recent measurements show the upper atmosphere is over 400 degrees Celsius, and in the polar regions as much as 700 degrees Celsius. In the words of Ruby Rhod from the movie The Fifth Element, “It’s Hot Hot Hot!”

With such little sunlight reaching Jupiter, how can its atmosphere be so warm? The team found it has to do with Jupiter’s aurora. On Earth, we have aurora all the time. More popularly known as the northern lights, this glow of the upper atmosphere occurs when ions from the solar wind get caught in Earth’s magnetic field and strike our atmosphere at high speed. Jupiter’s magnetic field is much stronger than Earth’s, and so Jupiter’s aurora can be much more intense. So intense that it can heat Jupiter’s upper atmosphere.

Jovian aurora as seen by the Hubble Space Telescope. Credit: NASA, ESA, and J. Nichols (University of Leicester)

The team showed that it is the polar region of Jupiter where the atmosphere is most heated, and the heat waves correlate with the cycle of Jupiter’s aurora activity. They also studied how this heat is transferred, so that much of Jupiter’s upper atmosphere is hyper-warm. Interestingly, this kind of strong electromagnetic heating is similar to what happens to the Sun’s upper atmosphere.

The Sun is obviously much larger and hotter than Jupiter, with a surface temperature of nearly 5,500 degrees Celsius, but you would still expect the uppermost region of its atmosphere to be cooler than its surface. After all, it’s very cold in space. But observations of the Sun show that its most diffuse upper layer, known as the corona, has a temperature of millions of degrees. This was a long-standing mystery until we finally figured out that solar flares and realignments of the Sun’s magnetic field were heating the corona. It turns out electromagnetism can hold a lot of energy.

Since Jupiter has such a warm upper atmosphere, this could help explain long-lasting weather patterns in its cloud region. After all, storms are powered by a varied temperatures in different regions, such as how the warm tropical ocean on Earth powers hurricanes as the northern hemisphere grows cooler in autumn. Similar temperature variations in Jupiter’s atmosphere could drive the great storms we observe.

In July 2016, NASA’s Juno space probe reached Jupiter, becoming the second spacecraft in history to orbit the gas giant (the first being the Galileo probe that orbited Jupiter from 1995 to 2003). The data it has sent back has led to new revelations about the Jovian atmosphere, magnetosphere, gravitational field, structure, and composition. While its primary mission was intended to only last until 2018, a mission extension means that Juno will continue to orbit Jupiter’s poles (a perijove maneuver) and send back stunning images and data until 2025.

Recently, a team of citizen scientists led by mathematician and software developer Gerald Eichstädt used images taken by the probe’s visible-light camera/telescope (the JunoCam) to create a 3D animation of Jupiter’s upper atmosphere. Eichstädt’s animation was presented at the 2022 Europlanet Science Congress (EPSC), which took place from September 18 – 23 in Granada, and shows the relative heights of the cloud tops of Jupiter that reveal delicately textured swirls and peaks. Eichstädt’s work also showcased the potential for citizen science and public engagement with today’s missions.

The Junocam was initially put on board to increase public engagement by taking raw images that are made available in a public gallery. Citizen scientists can then download the images, process them, upload the finished creations, and share them with the world. In this case, a worldwide team of citizen scientists, working closely with professional astronomers and the Juno team, demonstrated that JunoCam data could also be used to create stunning visuals and valuable science. As Eichstätd stated in a Europlanet Society press release:

“The Juno mission provides us with an opportunity to observe Jupiter in a way which is essentially inaccessible by Earth-based telescopic observations. We can look at the same cloud features from very different angles within only a few minutes. This has opened up a new opportunity to derive 3D elevation models of Jupiter’s cloud tops. The images of the wonderful chaotic storms on Jupiter seem to come to life, showing clouds rising at different altitudes.”

The images used to create the animation were taken during Juno’s 43rd close flyby of Jupiter (its 43rd perijove maneuver), which took place on July 5th, 2022, when the probe was at a nominal altitude of 13,536.3 km (8,411 mi) above Jupiter’s cloud tops. These visible-light pictures once again revealed intimate details about Jupiter’s atmosphere, including the swirling cloud formations near the planet’s north pole, reaching depths of over 50 km (30 mi) and hundreds of km in diameter. A close-up view of these images can be seen in the video posted above (courtesy of space animation artist Celestial).

Here’s one of the best videos we’ve seen of the last minutes of the Double Asteroid Redirection Test (DART) mission as it headed towards and slammed into the asteroid Dimorphos. This stabilized version of the last five-and-a-half minutes of images leading up to DART’s intentional collision with the asteroid was produced from NASA’s DART images. It was produced by the YouTube channel Spei’s Space News from Germany.

DART streamed these images from its DRACO camera back to Earth in real time as it approached the asteroid. This replay movie is 10 times faster than reality, except for the last six images, which are shown at the same rate that the spacecraft returned them. DRACO stands for Didymos Reconnaissance and Asteroid Camera for Optical navigation.

Below you can see the real-time views coming in to DART’s mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. The team can be seen cheering, clapping and giving each other high fives as the spacecraft performed its heroic duty, which was to intentionally collide with an asteroid in attempt to deflect it, a technique known as kinetic impact.

Dimorphos is a small asteroid moonlet, just 530 feet (160 meters) in diameter. It orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. Neither asteroid poses a threat to Earth, and the impact should change the way Dimorphos orbits Didymos, making the duo the perfect target for this test. NASA says that DART’s impact demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.

DART launched on November 24, 2021, and after 10 months of flying about 7 million miles (11 million kilometers through space, caught up with Dimorphos. DART weighed 1,260-pounds (570-kilograms) and crashed into the asteroid at roughly 14,000 miles (22,530 kilometers) per hour, which is expected to have slightly slowed the asteroid’s orbital speed.