Exploration of the gas giants

[caltrek]

The Salty Belly of a Saturn Moon May Contain Building Blocks of Life
by Doris Ellin Urrutia
December , 2023

Introduction:

(Inverse) In 2017, the Cassini spacecraft barrelled toward Saturn for the final time. NASA officials had elected to terminate the mission in a death dive. Obliterating the probe in a controlled maneuver would safeguard Saturn’s precious rings, moons, plus whatever else Cassini’s Earthly material could damage, or even contaminate. Like, perhaps, life.

Currently, scientists have never detected biosignatures in another world. But space exploration is providing tantalizing ideas. The latest such notion comes from a frigid moon of Saturn. The work is detailed in a study published this week in the journal Nature Astronomy.

Six years before its fiery finale, Cassini flew through plumes of gas coming from Saturn’s moon Enceladus. The spray was coming through cracks on its icy surface. It was a natural delivery service, giving Cassini’s INMS, or Ion and Neutral Mass Spectrometer, a special taste of what’s inside the moon.

WHAT’S IN THE SPRAY?

Astronomers have been studying INMS data since Cassini’s 2011 and 2012 rendezvous of the plumes. So far, they’ve found compelling evidence that Enceladus may have conditions favorable to life. Inside the gaseous spray there was the presence of water, carbon dioxide, methane, ammonia, and molecular hydrogen. This suggests that life could potentially emerge far away from the Sun in another part of the solar system.

But that’s a big maybe. “We don't yet know how life originated on Earth, so it's difficult to say what the necessary conditions would be on Enceladus,” Jonah Peter, a graduate student at Harvard University and lead author of the new paper, tells Inverse.

Read more here: https://www.inverse.com/science/salty- ... cks-life

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NASA's Juno to get close look at Jupiter's volcanic moon Io on Dec. 30
https://phys.org/news/2023-12-nasa-juno ... -moon.html
by NASA

NASA's Juno spacecraft will on Saturday, Dec. 30, make the closest flyby of Jupiter's moon Io that any spacecraft has made in over 20 years. Coming within roughly 930 miles (1,500 kilometers) from the surface of the most volcanic world in our solar system, the pass is expected to allow Juno instruments to generate a firehose of data.

"By combining data from this flyby with our previous observations, the Juno science team is studying how Io's volcanoes vary," said Juno's principal investigator, Scott Bolton of the Southwest Research Institute in San Antonio, Texas. "We are looking for how often they erupt, how bright and hot they are, how the shape of the lava flow changes, and how Io's activity is connected to the flow of charged particles in Jupiter's magnetosphere."

A second ultra-close flyby of Io is scheduled for Feb. 3, 2024, in which Juno will again come within about 930 miles (1,500 kilometers) of the surface.

The spacecraft has been monitoring Io's volcanic activity from distances ranging from about 6,830 miles (11,000 kilometers) to over 62,100 miles (100,000 kilometers), and has provided the first views of the moon's north and south poles. The spacecraft has also performed close flybys of Jupiter's icy moons, Ganymede and Europa.

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Juno Probe Completes Ultra-Close Flyby of Volcanic Moon Io
Jupiter's innermost moon is the latest target of Juno's extended mission.
By Ryan Whitwam January 3, 2024
https://www.extremetech.com/science/jun ... ic-moon-io

NASA's Juno spacecraft arrived in the Jovian system in 2016, tasked with studying the solar system's largest planet up close. Of course, Jupiter also has the most moons in the solar system (by a hair), and Juno has had the opportunity to scan a few of those, as well. Its most recent flyby reveals the volcanic moon Io in all its sulfuric glory.

In order to study Jupiter, the spacecraft has to remain in a highly eccentric orbit. This minimizes the amount of time Junop spends close to the gas giant, which produces intense bands of radiation that could fry the probe's electronics. These long, swooping orbits also put Juno in close proximity to the planet's inner moons. In the past, Juno has conducted flybys of Ganymede and Europa. There was another Io flyby in 2022, but the spacecraft's closest approach was 64,000 km (40,000 miles). On Dec 30, Juno zipped over the surface at an altitude of just 1,500 km (930 miles).

Io is a bit larger than Earth's moon, making it the third largest in the Jovian system. The constant pull of Jupiter's gravity causes tidal heating, which has produced an impressive 400 active volcanoes on the moon, belching out plumes of sulfur and sulfur dioxide. In the image above, you can see some sizable volcanic features, including the largest on the entire moon. It's Loki Patera, the dark circle toward the lower right. This 202-kilometer (126-mile) depression contains a lava lake, which shows evidence of frequent surface changes.

[wjfox]

Neptune and Uranus seen in true colours for first time

2 hours ago

Our ideas of the colours of the planets Neptune and Uranus have been wrong, research led by UK astronomers reveals.

Images from a space mission in the 1980s showed Neptune to be a rich blue and Uranus green.

But a study has discovered that the two ice giant planets are both similar shades of greenish blue.

It has emerged that the earlier images of Neptune had been enhanced to show details of the planet's atmosphere, which altered its true colour.

"They did something that I think everyone on Instagram will have done at some time in their life, they tweaked the colours," Prof Catherine Heymans, Astronomer Royal for Scotland and a University of Edinburgh astrophysics professor, told BBC Radio 4's Today. "They accentuated the blue just to reveal the features that you can see in Neptune's atmosphere, and that's why the image looks very blue, but in reality, Neptune is actually pretty similar to Uranus."

https://www.bbc.co.uk/news/science-environment-67892275

[raklian]

Neptune and Uranus seen in true colours for first time

Uranus looks quite bleached, eh?

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Titan's 'magic islands' are likely to be honeycombed hydrocarbon icebergs, finds study
https://phys.org/news/2024-01-titan-mag ... arbon.html
by Liza Lester, American Geophysical Union

Titan's "magic islands" are likely floating chunks of porous, frozen organic solids, a new study finds, pivoting from previous work suggesting they were gas bubbles. The study was published in Geophysical Research Letters.

A hazy orange atmosphere 50% thicker than Earth's and rich in methane and other carbon-based, or organic, molecules blankets Saturn's largest moon, Titan. Its surface is covered with dark dunes of organic material and seas of liquid methane and ethane. Stranger yet are what appear in radar imagery as shifting bright spots on the seas' surfaces that can last a few hours to several weeks or more.

Scientists first spotted these ephemeral "magic islands" in 2014 with the Cassini-Huygens mission and have since been trying to figure out what they are. Previous studies suggested they could be phantom islands caused by waves or real islands made of suspended solids, floating solids, or bubbles of nitrogen gas.

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NASA Installs Europa Clipper Spacecraft's Scientific Instruments
JPL engineers can finally test the complete spacecraft ahead of launch in October.
By Ryan Whitwam February 2, 2024

NASA hopes to send the Europa Clipper on its way toward Jupiter later this year, and work is ongoing to get the spacecraft ready. There's a chance that Europa's subsurface ocean could have the ingredients for life, but reaching Europa and surviving in orbit of Jupiter is no simple feat. NASA says the mission has passed a major milestone: All nine instruments designed for the mission have been installed aboard Europa Clipper. This finally allows NASA engineers to test the complete spacecraft for the first time.

The Europa Clipper is being prepared for its mission at NASA's Jet Propulsion Laboratory (JPL) in southern California. In October, the spacecraft will be loaded aboard a SpaceX Falcon Heavy rocket to begin its long journey to the Jovian system. NASA initially wanted to launch this mission with the Space Launch System, but delays in building those rockets left NASA with little choice. SpaceX is the only launch services provider with a super-heavy lift vehicle ready to go.

This period in Europa Clipper development is vitally important to the mission's success. The Clipper gets its name from the way it will explore Jupiter's moon. Europa lies well within the intense radiation field of Jupiter, meaning the probe would be at great risk of failure if it entered the orbit of the moon and stayed there. So, the mission will employ a strategy similar to the one that kept the Juno spacecraft alive. It will swing past Europa 44 times, collecting more data on each flyby before its eccentric orbit takes it out of the danger zone.

https://www.extremetech.com/science/nas ... nstruments

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Juno Completes Second Flyby of Volcanic Moon Io
The rest of Juno's mission will focus once again on Jupiter.
By Ryan Whitwam February 6, 2024

NASA's Juno spacecraft began its scientific operations looping around the gas giant Jupiter, providing the most stunning images yet of the solar system's largest planet. But that was in 2016—Juno is still operational, but it's shifted focus to some of Jupiter's many moons. Late last year, Juno completed a close flyby of Io, and now the probe has done it again, zipping over the craggy surface of Jupiter's most volcanic moon to beam back photos of the alien landscape. Enjoy it—these might be the last up-close images of Io we get for a long time.

The Juno team says the latest flyby took place exactly as planned on Feb. 3, offering another glimpse of the moon's surface from a mere 930 miles (1,500 kilometers) above the surface. And what a surface it is—Io is Jupiter's innermost moon, which subjects Io to the intense tug of the gas giant's gravity. This results in tidal heating, which keeps the interior of Io toasty. That's why the moon has an estimated 400 active volcanoes.

https://www.extremetech.com/science/jun ... ic-moon-io

[Time_Traveller]

Saturn’s ‘Death Star’ moon has hidden ocean under its crust, say scientists

Wed 7 Feb 2024 16.00 GMT

A moon of Saturn that resembles the Death Star from Star Wars because of a massive impact crater on its surface has a hidden ocean buried miles beneath its battered crust, researchers say.

The unexpected discovery means Mimas, an ice ball 250 miles wide, becomes the latest member of an exclusive club, joining Saturn’s Titan and Enceladus and Jupiter’s Europa and Ganymede as moons known to harbour subterranean oceans.

“It’s quite a surprise,” said Valéry Lainey, an astronomer at the Observatoire de Paris in France. “If you look at the surface of Mimas, there’s nothing that betrays a subsurface ocean. It’s the most unlikely candidate by far.”

Peculiarities in Mimas’s orbit had led astronomers to entertain two possibilities: either it contained an elongated core shrouded in ice, or an internal ocean that allowed its outer shell to shift independently of the core.

By analysing thousands of images from Nasa’s Cassini mission to Saturn, Lainey and his colleagues reconstructed the precise spin and orbital motion of Mimas as it looped around the gas giant. Their calculations showed Mimas must possess a hidden subsurface ocean to move the way it does.

https://www.theguardian.com/science/202 ... dden-ocean