Artist's view of the #aurorae of #Jupiter's moon #Ganymede.
The bands of aurorae and their movement are only possible due to a magnetic field generated by movements of salty water underneath the moon's icy crust.
The salty internal ocean potentially contains more water than all of Earth's oceans combined.
Backyard astronomy with the kids is fun. Caught this photo using my phone, handheld against binoculars on a tripod, looking at Jupiter last night. The visible moons, from left to right, are Ganymede, Europa, and Callisto.
The NASA administrator at the time,
Sean O'Keefe,
sought to develop a new generation of spacecraft 
powered by nuclear reactors as part of what he called #Project #Prometheus.
He believed that a mission with Europa as its main target offered a perfect test case for the technology,
and thus, the "Jupiter Icy Moons Orbiter"
was born.
This was a highly ambitious mission. A typical spacecraft uses on the order of a few hundred watts of power.
This probe, powered by a nuclear reactor, would have had on the order of 100,000 watts of power.
The Jupiter Icy Moons Orbiter was audacious in other ways,
such as using a landing component to directly sample Europa's ice.
Unfortunately, the mission also became insanely expensive,
with a budget blasting past $20 billion.
When O'Keefe was replaced by a new administrator in 2005, Mike Griffin, the Jupiter Icy Moons Orbiter was put on ice.
Galileo sparked an incredible amount of interest in Europa.
First, NASA tried a fast, cheap mission.
Then the agency worked on the most ambitious spacecraft concept ever put forward.
Both failed. A decade was lost.
A new champion emerges
In 2000, a conservative Texas attorney named
#John #Culberson won election to the US House of Representatives for the first time.
For a time, he focused on local issues, such as freeway construction in the greater Houston area.
However, after the cancellation of the Jupiter Icy Moons Orbiter, he was furious.
Most people in Congress, to the extent they care about NASA, do so for parochial interests and local jobs.
For Culberson, that meant Johnson Space Center, which was located in a district adjacent to his.
But Culberson was also deeply interested in planetary exploration,
and he wanted to be associated with NASA's first mission to find life on another world.
So he became an advocate of funding for a NASA center on the opposite side of the country,
the Jet Propulsion Laboratory,
which led the agency's robotic exploration efforts.
As a member of the House Appropriations Committee, Culberson began to tuck funding into NASA's budget for the ongoing study of a Europa orbiter.
During this period, as a science reporter for the Houston Chronicle,
I began to bump into Culberson at various events around town.
He was both a conservative Christian politician and a life-long science geek.
Skeptic that I am, I wondered if his interest in science was an act to ingratiate himself with constituents,
given that the Houston area has a large biomedical community.
Eventually, however, I began to realize it was totally genuine.
He is fascinated by the Solar System and wants to know more about its origin and whether it harbors life on worlds other than Earth.
We bonded over this mutual interest.
In the meantime, there were more furtive starts on a Europa mission.
In 2007, NASA began studying mission concepts for #Europa and #Ganymede in the Jovian system,
as well as the moons #Titan and #Enceladus around Saturn.
Working with international partners two years later, NASA eventually down-selected to a combination mission in which the US space agency built an orbiter for Europa
and the European Space Agency one for Ganymede
(eventually, this European mission did launch, as #JUICE, in 2023).
NASA's part was known as the Jupiter Europa Orbiter.
However, a year later, new NASA Administrator Charles Bolden was looking for ways to cut the agency's budget.
By now, you probably know what was about to happen.
Sure enough, the Jupiter Europa Orbiter's budget was ballooning to above $3 billion.
And there was another problem
—Mars became ascendant in the agency's exploration interests.
"For the first time in 20 years, #Mars was brought into competition with the outer planets," Brown said.
"The top endorsement in a painful budget environment was a Mars Sample Return. As a result, the Jupiter Europa Orbiter died."
Once again, Culberson was not happy. But this time, he would soon be in a position to do something about it.
During its flyby of Earth the, Jupiter Icy Moons Explorer (#Juice) probe found ingredients for #life in Earth’s #atmosphere.
The #flyby provided the opportunity to test out and calibrate Juice’s science instruments in space, ensuring that they are ready for arrival at #Jupiter.
In the Jupiter system, Juice will fly through dust and gas emitted from the icy moons #Europa, #Ganymede and #Callisto, and search for signatures of life under their icy crusts.
#astrobiology
https://www.esa.int/Science_Exploration/Space_Science/Juice/Juice_confirms_that_Earth_is_habitable/
For #MythologyMonday -- let's talk AMBROISA -- the food/drink of the #GreekGods!
It is said to give the gods their immortality/longevity & our guy Ganymede (of #Aquarius mythology fame) is one of the servers of ambrosia for the gods (after Zeus, you know, kidnapped him...
)
More on Ambrosia here: https://en.wikipedia.org/wiki/Ambrosia (and we have an episode on the #mythology and #astronomy of the #constellation Aquarius)
It's the Day of Zeus / Jupiter's Day / #Thursday! 
"[Constellation] Aquila. This is the eagle which is said to have snatched #Ganymede up and given him to his lover, Jupiter [Zeus] [...] And so it seems to fly above Aquarius, who, as many imagine is Ganymede."
Pseudo-Hyginus, Astronomica 2. 16
#Ganymedes and #Zeus as an eagle, Roman mosaic, 2nd century CE
@antiquidons @mythology #DayOfZeus #GreekRomanArt #Jupiter #MosaicMonday
If #Saturn’s cratered #moon #Mimas has liquid #water beneath its surface, #ocean worlds might be far more common than we thought.
Only #Jupiter’s #Europa, #Callisto, and #Ganymede and Saturn’s #Enceladus and #Titan have confirmed oceans, but several more moons of Saturn, #Uranus, and #Neptune are the subject of exploration.
But simulation suggests that Mimas’ subsurface ocean rests under 20–30 km of ice. As much as 50%–60% of Mimas’s total volume could be liquid water.
A découvrir sur https://reves-d-espace.com/lune-ganymede-juno-webb/
His Dark Materials
Dark craters Chrysor and Aleyn in Memphis Facula on Ganymede.
Captured by the Galileo Spacecraft in 1996
Credits: NASA/JPL/Brown University
https://photojournal.jpl.nasa.gov/catalog/PIA01607
It's the Day of Zeus / Jupiter's Day / #Thursday!
Wall decoration of #Ganymedes seemingly just getting off #Zeus' lap...
#Neoclassical relief, Hamburger Kunsthalle.
https://www.maicar.com/GML/Ganymedes.html
@antiquidons @mythology #DayOfZeus #ancMedReception #Ganymede
Salts and organics on #Ganymede’s surface observed by the #JIRAM spectrometer onboard #Juno: https://www.nature.com/articles/s41550-023-02107-5.epdf?sharing_token=_L4lYGL3OUjY_7me7vvu0tRgN0jAjWel9jnR3ZoTv0OZjcl3SIKPp0fHDrV0bzSJgkDjP3hzW87CKZ-qqS0gcNIM63XNEgLGRqFJj-WmQ_p7RsvjGt6-ZqJBEeE404BDUoEn-KUUME45umCN_6uGSQ1BZSVus6q1YgEvPg9pr4E%3D -> Salts and Organics Observed on Ganymede’s Surface by NASA’s Juno: https://www.jpl.nasa.gov/news/salts-and-organics-observed-on-ganymedes-surface-by-nasas-juno - data collected by NASA’s Juno mission indicates a briny past may be bubbling to the surface on Jupiter’s largest moon.
Salts and Organics Observed on Ganymede’s Surface by NASA’s Juno https://www.nasa.gov/missions/juno/salts-and-organics-observed-on-ganymedes-surface-by-nasas-juno/ #NASA #Juno #Ganymede #JupiterMoons #TheSolarSystem
Full moon, Jupiter and two of its Galilean moons. (Ganymede and Europa)
This is what my camera captured in terms of location on the frame, but this is a heavily edited image.
The moon required a short exposure, the disk of Jupiter a longer one, and the Galilean moons needed the longest.
This is a composite image.
I pushed the moon's contrast hard to show the impact/ray structures clearly.
I enlarged the dots of the Galilean moons so that they were visible, especially on smaller screens.
I pushed contrast of the disk of Jupiter, and two of the widest cloud bands are visible if you zoom in. Not too bad for a 400mm focal length lens.
#Moon
#Jupiter
#Ganymede
#Europa
#Astronomy
#Astrophotography
Ocean #moons of the outer solar system hint at ice volcanoes, #hydrothermal vents, and the tantalizing chance of #habitability.
#Jupiter’s moons #Europa and #Ganymede, #Saturn’s moons #Enceladus and #Titan, and more objects in the outer solar system have turned out to be remarkably active ocean worlds.
They are filled with ice and vast seas of water. They may have hydrothermal vents feeding into oceans. All of these characteristics add up to potential #habitability.
https://eos.org/features/cryovolcanisms-song-of-ice-and-fire
Hydrogen peroxide at the poles of #Ganymede: https://www.science.org/doi/10.1126/sciadv.adg3724 -> "the discovery of #HydrogenPeroxide, a radiolysis product of water ice, specifically constrained to the high latitudes" -> James #Webb Space Telescope sees Jupiter moons in a new light: https://news.berkeley.edu/2023/07/27/james-webb-space-telescope-sees-jupiter-moons-in-a-new-light/
@AimeeMaroux @antiquidons @histodons @mythology The myth of #Ganymede leads to what may be the raunchiest homoerotic passage of #Plato in the Phaedrus:
>"[255c] then the fountain of that stream which Zeus, when he was in love with Ganymede, called “desire” flows copiously upon the lover; and some of it flows into him, and some, when he is filled, overflows outside;"
Although it's mostly how *Eros *as desire helps elevate the soul to the Gods, I think we can read the cruder sex joke into it!
It's the Day of Zeus / Jupiter's Day / #Thursday!
#Zeus pursuing #Ganymedes who is playing with a hoop. Hoops (krikoi), were probably made of bronze, iron, or copper, and were driven with a stick called the "elater". Hoop driving was practiced in the gymnasium and was also used for tumbling & dance with different techniques.
Zeus and Ganymedes, red-figure vase painting, National Archaeological Museum #Athens
#DayOfZeus #Ganymede #Mythology #LGBTQhistory @antiquidons @histodons @mythology
It's the Day of Zeus / Jupiter's Day / #Thursday!
Bronze mirror case depicting the abduction of #Ganymedes by Zeus. Several people are standing around when #Zeus lifts up the Trojan prince into the air but they can't do anything to stop it.
Late #Etruscan from Palestrina, Italy
#DayOfZeus #Ganymede #Mythology #EtruscanArt #antiquidons @antiquidons @histodons @mythology
It's the Day of Zeus / Jupiter's Day / #Thursday!
Meet these superb golden earrings consisting of a honeysuckle palmette below which hangs a finely worked 3D figure of #Ganymedes in the clutches of #Zeus, who has assumed the guise of an eagle to carry him off to Mount Olympos. The airborne theme is ingeniously adapted here as earrings hang freely in space.
Greek, ca. 330–300 BCE
#DayOfZeus #Ganymede #Mythology #ancientGreece #GreekRomanArt #antiquidons @antiquidons @histodons @mythology
