The Galilean Moons, named in honor of Galileo Galileo, who first observed them in 1610, are a fascinating collection of satellites. For decades, scientists have been immensely fascinated by the three icy companions – Europa, Ganymede, and Callisto – which have oceans in their interiors that possibly support life. But Io has also been a focal point of interest lately, owing to the volcanic activity on its surface and lava plumes reaching 300 to 500 km (186 to 310 mi) into space. Since 2016, NASA’s Juno probe has provided stunning images of Io as it continues to orbit its main science objective, Jupiter.
The latest was acquired by the Juno probe’s main camera (JunoCam) on July 31st, 2023, at 05:03 AM UTC (01:03 AM EDT; July 30th, 10:03 PM PDT) and showed Prometheus spewing out lava. This active volcano is located within a 28-km (17-mi) -wide volcanic pit named Prometheus Patera on the hemisphere facing away from Jupiter. Prometheus is known for its regular eruptions, hence its nickname in the astrogeological community, “Old Faithful of Io.” A processed image of the eruption was shared by the NASA Planetary Science Division via Twitter (see below).
It’s been over twenty-two years since we’ve been able to see Jupiter’s enticing moon Europa close-up. But now the Juno spacecraft has made its closest pass of Europa, sending back some amazing pictures of the icy mini-world, which likely has an ocean that contains more water than all of Earth’s oceans combined.
Observations from the spacecraft’s 45th orbit around Jupiter brought it close enough to give us some of the best views of Europa that we’ve ever had.
Over the course of a brief two-hour opportunity, NASA’s Juno spacecraft captured a rare close look at Europa, an ice-covered moon of Jupiter that’s thought to harbor a hidden ocean — and perhaps an extraterrestrial strain of marine life.
Juno has been orbiting Jupiter since 2016, but this week brought the best opportunity to look at Europa, which is the prime target for investigation by NASA’s Europa Clipper probe in the 2030s. On Sept. 29, the orbiter buzzed over the moon’s surface at a velocity in excess of 52,000 mph (23.6 km per second), and at an altitude of 352 kilometers (219 miles).
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.
During Juno’s extended mission, every orbit is like a new adventure. Each orbit is a little different, and NASA says the natural evolution of Juno’s orbit around Jupiter provides a wealth of new science opportunities.
But for most of us, what we look forward to on every perijove – the point in each orbit where the Juno spacecraft comes closest to the gas giant – are the incredible images taken by the camera on board, JunoCam. As Juno’s “eyes,” the camera provides a unique vantage point no other spacecraft has been able to give us.
Well, hello there old friend! This week the Juno mission to the Jupiter system made the first close flyby of Jupiter’s giant moon Ganymede, and as you might guess, the images are spectacular. This is the first time we’ve seen a close-up view of the Solar System’s largest moon since the Galileo mission 20 years ago. Voyager gave us the first views of Ganymede 40 years ago. Now, planetary scientists will be able observe any changes in Ganymede’s surface over time.
But first, the image editing gurus back on Earth are having a go at the raw images sent back by Juno. Our lead image comes from Gerald Eichstädt, who worked his magic to bring out the details of Ganymede, and it’s a stunner.
A new batch of images recently arrived at Earth from JunoCam, the visible light camera on board the Juno spacecraft at Jupiter. The camera has provided stunning views of the gas giant world since the spacecraft’s arrival in 2016. Citizen scientists and imaging enthusiasts act as the camera’s virtual imaging team, participating in key steps of the process by making suggestions of areas on Jupiter to take pictures and doing the image editing work.
This lead image, edited by Kevin Gill, is another stunner: a look straight down into a giant storm.
And we like Kevin’s attitude about this whole process:
Are spirits amongst the clouds of Jupiter? The answer might be yes! A recent publication in the Journal of Geophysical Research: Planets has identified what appear to be “Sprites” in the Jovian Atmosphere.
In European Folklore, ‘Sprites’ (derived from Latin ‘spiritus’ or spirit) were elemental and ethereal beings visiting Earth. The term is fitting for “lightning sprites”, a natural meteorological phenomenon with many eye-witness testimonies but not captured on camera until 1989. Created by lightning discharges in Earth’s atmosphere, sprites are part of larger family of phenomena called TLE’s, or “Transient Luminous Events”, that last for only fractions of a second.
Artist Mik Petter has created a vibrant new piece of art based on JunoCam images of Jupiter’s Great Red Spot (GRS). The piece makes use of fractals, which are recursive mathematical creations; increasingly complex patterns that are similar to each other, yet never exactly the same.