The final time a spacecraft obtained this near Jupiter’s moon Io was greater than 20 years in the past, a blink of a watch on a typical geological timescale. Most planetary our bodies in our Photo voltaic System would not exhibit a lot change in a few many years.
However Io is totally different, with volcanic eruptions recurrently remaking components of the moon’s crust. Which means there is a good probability one thing on Io has modified since NASA’s Galileo orbiter final encountered it in 2002.
NASA’s robotic Juno spacecraft is delivering the contemporary knowledge on Io with a sequence of flybys, every getting nearer to Jupiter’s volcanic moon till a pair of close-up encounters at a variety of lower than 1,000 miles (about 1,500 kilometers) in December and February.
The newest flyby on July 30 introduced the solar-powered Juno probe about 13,700 miles (22,000 kilometers) from Io’s tortured floor. Juno’s science devices have been lively for the flyby, with the spacecraft’s infrared mapping instrument tuned to detect warmth signatures from volcanic eruptions and lava flows and an optical imaging digital camera taking long-range footage of Io.
The $1.1 billion Juno mission launched 12 years in the past this week and arrived in orbit round Jupiter on July 4, 2016. Its unique purpose was to review Jupiter’s ambiance and deep inside. One in all its prime science outcomes was discovering proof for a big, doubtlessly dissolved core inside Jupiter, upending a speculation that Jupiter had a smaller, stable core at its middle.
Juno is now on an prolonged mission, and scientists solid a wider internet of science observations for the spacecraft’s second act. The tug of gravity from Jupiter is of course altering Juno’s orbit over time, bringing the spacecraft throughout the paths of the enormous planet’s largest moons. Juno flew near Jupiter’s largest moon, Ganymede, in 2021 after which visited Europa for a fleeting encounter in September 2022.
Io, barely bigger than Earth’s Moon, will get essentially the most sustained look from Juno, which began long-distance observations of the volcanic moon final 12 months. In Might, Juno flew lower than 22,000 miles (35,000 kilometers) from Io, adopted by the nearer flyby on July 30. The spacecraft will see Io once more in October earlier than establishing for what Juno’s lead scientist, Scott Bolton, calls the “climax” of the marketing campaign—the 1,500-kilometer flybys set for December 30 and February 3.
Some issues by no means change
Whereas Io is noteworthy for its fixed adjustments, scientists are discovering at the least one consistency about Io: an apparently frequently erupting volcano referred to as Prometheus, additionally dubbed the “Previous Devoted of Io.”
NASA’s Voyager spacecraft first detected the volcano in 1979, and the Galileo orbiter made quite a few observations of Prometheus throughout its eight-year tour of the Jupiter system from 1995 by way of 2003. The Pluto-bound New Horizons probe additionally noticed the volcano erupting in 2007.
Juno has proven that the volcano remains to be going, spewing a plume of fuel and dirt excessive above the evening facet of Io.
Contemporary from Jupiter, we’ve got new views of its lively moon Io, due to the #JunoMission. JunoCam even caught a glimpse of a volcanic plume! That is Prometheus, the “Previous Devoted of Io.” Extra pictures: https://t.co/1Vm8NwGA6R pic.twitter.com/YpTAf6IJCu
— NASA Photo voltaic System (@NASASolarSystem) August 4, 2023
Io is essentially the most volcanically lively physique within the Photo voltaic System. The gravitational pull from Jupiter and the moons Ganymede and Europa are stretching Io, producing tidal forces that create warmth and set off volcanic eruptions.
For comparability, Io’s stable floor bulges by as a lot as 330 ft (100 meters) throughout every tidal cycle, in line with NASA. Essentially the most excessive tides on Earth—in liquid water—range about 60 ft (18 meters).
Throughout Juno’s Might flyby with Io, the spacecraft’s digital camera captured a view of a area of Io referred to as Volund. There are adjustments afoot right here.
“Once I in contrast it to visible-light pictures taken of the identical space throughout Galileo and New Horizons flybys (in 1999 and 2007), I used to be excited to see adjustments at Volund, the place the lava circulation area had expanded to the west and one other volcano simply north of Volund had contemporary lava flows surrounding it,” stated Jason Perry of the College of Arizona’s HiRISE Operations Heart in Tucson. “Io is thought for its excessive volcanic exercise, however after 16 years, it’s so good to see these adjustments up shut once more.”
Scientists have proposed sending a devoted spacecraft to systematically research Io, just like the best way NASA’s Europa Clipper mission set for launch subsequent 12 months will present a more in-depth have a look at the icy moon regarded as one of many Photo voltaic System’s most promising areas for locating doable life.
However NASA has not accepted an Io mission. Which means Juno’s observations within the coming months will in all probability yield the one shut views of Io for at the least the subsequent decade.