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Sent primarily to investigate the origin and evolution of Jupiter, Juno has been able to take in bonus observations of the planet's four major moons - Callisto, Ganymede, Europa and now Io. It performed its close flyby of Ganymede in 2021, and of Europa earlier this year. These passes produced some novel insights from Juno's microwave radiometer. Intended to look deep into the clouds of Jupiter, this instrument has also been able to see down through the ice layers of Ganymede and Europa for tens of kilometres. These two moons are of particular interest because they're both thought to hide...

Explanation: The strangest moon in the Solar System is bright yellow. The featured picture, an attempt to show how Io would appear in the "true colors" perceptible to the average human eye, was taken in 1999 July by the Galileo spacecraft that orbited Jupiter from 1995 to 2003. Io's colors derive from sulfur and molten silicate rock. The unusual surface of Io is kept very young by its system of active volcanoes. The intense tidal gravity of Jupiter stretches Io and damps wobbles caused by Jupiter's other Galilean moons. The resulting friction greatly heats Io's interior, causing molten rock to...

Explanation: Jupiter and its moons move like our Sun and its planets. Similarly, Jupiter spins while its moons circle around. Jupiter’s rotation can be observed by tracking circulating dark belts and light zones. The Great Red Spot, the largest storm known, rotates to become visible after about 15 seconds in the 48-second time lapse video. The video is a compilation of shorts taken over several nights last month and combined into a digital recreation of how 24-continuous hours would appear. Jupiter's brightest moons always orbit in the plane of the planet's rotation, even as Earth’s spin makes the whole system...

One of Jupiter's tenuous rings can be seen in this infrared image. (NASA/ESA/CSA/STScI/Judy Schmidt) Given its similarities to its neighbor, Saturn, it seems natural to ask why Jupiter doesn't also have a magnificent, extensive system of visible rings. Alas, it's not the reality. While Jupiter does have rings, they're thin, tenuous, flimsy things of dust, visible only when back-lit by the Sun. According to new research, these discount rings lack bling because Jupiter's posse of chonky Galilean moons keep discs of rock and dust from accumulating the way they do around Saturn. "It's long bothered me why Jupiter doesn't have...

Explanation: What are those spots on Jupiter? Largest and furthest, just right of center, is the Great Red Spot -- a huge storm system that has been raging on Jupiter possibly since Giovanni Cassini's likely notation of it 357 years ago. It is not yet known why this Great Spot is red. The spot toward the lower left is one of Jupiter's largest moons: Europa. Images from Voyager in 1979 bolster the modern hypothesis that Europa has an underground ocean and is therefore a good place to look for extraterrestrial life. But what about the dark spot on the upper...

Iowa and Tennessee are two of the five states which have restored Constitutional Carry so far in 2021. In both states the Constitutional Carry (permitless carry) bills took effect on Thursday, 1 July, just ahead of Independence Day, July 4th. Constitutional Carry is a reasonable facsimile of the state of the law when the Second Amendment was ratified in 1791. At the time, no state or federal law required government permission in order to carry personal weapons, either openly or concealed.In Iowa, the Constitutional Carry bill contained other reforms. The bill was signed into law on 2 April by Governor...

NASA has a message for space lovers this month: Look up. The largest planet in the solar system, Jupiter, will be clearly visible June 10 — and to see its biggest moons you'll only need to grab a pair of binoculars. NASA said the gas giant is at its "biggest and brightest this month" and will be visible all night. The planet will reach opposition, the annual occurrence when the Jupiter, Earth and the Sun are arranged in a straight line, with Earth in the center. So, mark your calendars for Monday, as it will be the best time of...

Welcome to "On This Day ... in Space!" where we peer back in our archives to find historic moments in spaceflight and astronomy. So enjoy a blast from the past with Space.com's Hanneke Weitering to look back at what happened on this day in space! On Nov.  21, 1676, the Danish astronomer Ole Rømer discovered the speed of light . Before Rømer figured it out, scientists thought that light travels instantaneously, or infinitely fast. Rømer disproved this almost by accident when he was studying Jupiter's moon Io. He was trying to figure out how long it takes Io to orbit Jupiter in hopes...

NASA’s Galileo spacecraft surprised scientists when it revealed that Jupiter’s moon Ganymede generated its own magnetic field. But new research shows Ganymede also creates incredibly powerful waves that rocket particles to enormous energies. Scientists revealed these huge electromagnetic waves while studying old data from Galileo, which orbited Jupiter from 1995 to 2003. The observations show another wild way that a moon can interact with the magnetic field of its planet. Jupiter’s radius is around 11 times that of Earth, but it is perhaps 20,000 times more magnetic. This generates an intense radiation environment around the planet. Typically, these waves around...

Io boasts more than 130 active volcanoes with an estimated 400 total, making it the most volcanically active place in the Solar System. Juno used its Jovian Infrared Aurora Mapper (JIRAM) to take spectacular photographs of Io during Perijove 7 last July... Juno’s Io looks like it’s on fire. Because JIRAM sees in infrared, a form of light we sense as heat, it picked up the signatures of at least 60 hot spots on the little moon on both the sunlight side (right) and the shadowed half. Like all missions to the planets, Juno’s cameras take pictures in black and...

Within the Jupiter system, there are 67 confirmed moons of varying size, shape and composition. In honor of Jupiter’s namesake, they are sometimes collectively referred to as the Jovians. Of these, the four largest – Io, Europa, Ganymede and Callisto – are known as the Galileans (in honor of their founder, Galileo Galilei). These four moons are among the largest in the Solar System, with Ganymede being the largest of them all, and even larger than the planet Mercury. In addition, three of these moons – Europa, Ganymede and Callisto – are all believed or known to have interior oceans...

Explanation: Some of the Solar System's largest moons rose together on February 23. On that night, a twilight pairing of a waning gibbous Moon and Jupiter was captured in this sharp telescopic field of view. The composite of short and long exposures reveals the familiar face of our fair planet's own large natural satellite, along with a line up of the ruling gas giant's four Galilean moons. Left to right, the tiny pinpricks of light are Callisto, Io, Ganymede, [Jupiter], and Europa. Closer and brighter, our own natural satellite appears to loom large. But Callisto, Io, and Ganymede are actually...

On August 4th Plymouth County Sheriff's department Sgt. Rick Singer stopped a man legally openly carrying a holstered pistol while walking.  Sgt. Singer asked for the man's permit, which was presented.    Sergent Singer would not accept the legal permit.  He persistently demanded a "paper permit" which he said was the "legal permit".   He keeps saying that the permit is simply a "courtesy card"  He was wrong, but he illegally confiscated the open carriers permit.   The entire affair was recorded on video:  Link to video The Sergeant claims that the picture on the permit is not recognizable, but wants...

Explanation: On June 30, Venus and Jupiter were close in western skies at dusk. Near the culmination of this year's gorgeous conjunction, the two bright evening planets are captured in the same telescopic field of view in this image taken after sunset from Bejing, China. As the two bright planets set together in the west, a nearly Full Moon rose above the horizon to the south and east. Imaged that night with the same telescope and camera, the rising Moon from the opposite part of the sky is compared with the planetary conjunction for scale in the digitally composited image....

A US radio telescope has captured images of an enormous lava lake on the surface of Io, one of the moons orbiting the planet Jupiter, the Puerto Rico Astronomy Society (PRAS) reported. "The new images clearly show an enormous lake of lava, fed from the subsoil and which exists permanently," PRAS vice president, professor and scientist Armando Caussade said in a statement. The Large Binocular Telescope Observatory in Arizona was the one that spotted the mass of lava in the region known as Loki Patera, a volcanic pit measuring approximately 200 kilometers (124 miles) in diameter. PRAS spokesman Juan Villafañe...

The dwarf planet Pluto and its system of five moons are about as mysterious as the underworld of antiquity that inspired their names. ... “We are still baffled by how the system formed,” says study co-author Mark Showalter, a senior research scientist at the Search for Extraterrestrial Intelligence (SETI) Institute. “I think everyone believes that, at some point in the distant past, a large object bashed into ‘proto-Pluto’ and the moons formed out of the debris cloud. However, after that point in the story, details get very sketchy.” Now, analysis of data collected from the Hubble Space Telescope following the...

Explanation: Our solar system's ruling giant planet Jupiter and 3 of its 4 large Galilean moons are captured in this single Hubble snapshot from January 24. Crossing in front of Jupiter's banded cloud tops Europa, Callisto, and Io are framed from lower left to upper right in a rare triple-moon conjunction. Distinguishable by colors alone icy Europa is almost white, Callisto's ancient cratered surface looks dark brown, and volcanic Io appears yellowish. The transiting moons and moon shadows can be identified by sliding your cursor over the image, or following this link. Remarkably, two small, inner Jovian moons, Amalthea and...

Angelenos will get their chance Friday to witness a rare celestial event when the shadows of three of Jupiter’s largest moons will fall upon Jupiter at the same time. Griffith Observatory will stay open one hour later than normal to allow visitors who are already at the park to watch the triple-shadow transit as Jupiter’s three moons – Io, Europa, and Callisto – will cross the planet’s disk throughout the evening. Three moon shadows will not appear simultaneously on Jupiter again, from Los Angeles, until 2032, according to the Observatory. As if the triple shadow transit weren’t enough, there will...

Explanation: A 24 minute sequence from top to bottom, this intriguing series of telescopic frames tracks the occultation of Io by Callisto, two of Jupiter's Galilean moons, from San Pietro Polesine, Italy, planet Earth. A challenging observational project using a small telescope, the two contrasting Jovian worlds are both slightly larger than Earth's Moon. In fact, bright, volcanic Io and dark, cratered Callisto are about 3,640 and 4,820 kilometers in diameter respectively. With Earth itself now crossing near the orbital plane of Jupiter's moons, astronomers are enjoying a season of Galilean moon mutual events ranging from eclipses to occultations. The...