{"id":545221,"date":"2026-07-17T00:11:28","date_gmt":"2026-07-17T00:11:28","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/545221\/"},"modified":"2026-07-17T00:11:28","modified_gmt":"2026-07-17T00:11:28","slug":"jupiters-strange-icy-moon-has-a-secret-ocean-making-it-one-of-the-best-places-to-search-for-life-in-our-solar-system","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/545221\/","title":{"rendered":"Jupiter’s strange icy moon has a secret ocean, making it one of the best places to search for life in our Solar System"},"content":{"rendered":"

At first glance, Jupiter\u2019s moon Europa might look less like a cradle for life and more like a cracked, frozen ball in the freezing outer reaches of our Solar System.<\/p>\n

Wrapped in a shell of solid ice almost 30 km (20 miles) thick, this distant moon of is blasted by intense radiation from its parent planet and its surface temperature never rises above \u2013160\u00b0C (\u2013260\u00b0F).<\/p>\n

Yet, beneath this hostile exterior lies one of the most promising places in the search for extraterrestrial life.<\/p>\n

Scientists believe that hidden under Europa’s icy crust is a global, liquid water ocean containing more than twice the water of all of Earth\u2019s oceans combined.<\/p>\n

\"ImageImage of Neptune by NASA’s Voyager 2 probe. Credit: NASA\/JPL-Caltech<\/p>\n

Warmed by the gravitational pull of Jupiter, which stretches and flexes the moon’s interior through tidal heating, Europa’s sub-surface ocean could possess the three key ingredients for life: liquid water, chemical elements and an energy source.<\/p>\n

And with missions like NASA’s Europa Clipper and the European Spacer Agency’s Juice spacecraft en route to study this icy enigma up close, it feels like we’re closer than ever to uncovering its secrets.<\/p>\n

Let’s explore some of the most fascinating mind-boggling facts about this captivating world of our Solar System.<\/p>\n

\"ImageImage of Jupiter\u2019s moon Europa captured by NASA’s Juno spacecraft during a flyby on 29 Septemebr 2022. Image data: NASA\/JPL-Caltech\/SwRI\/MSSS. Image processing: Bj\u00f6rn J\u00f3nsson (CC BY 3.0)
\nEuropa is the smallest and least massive of Jupiter\u2019s Galilean moons<\/p>\n

With a mean radius of around 1,500km (930 miles) and a mass of 4.7998 x 1022 kg, Europa is smaller and lighter than Ganymede<\/a>, Callisto<\/a> or Io<\/a>, the other three of Jupiter’s four large Galilean moons<\/a>.<\/p>\n

It\u2019s about 90% of the size of our own Moon, making it the sixth-largest moon in the Solar System.<\/p>\n

It\u2019s too small to be seen with the naked eye<\/p>\n

Europa isn\u2019t a naked-eye object. But neither is it particularly hard to find. <\/p>\n

hen Jupiter is at its best \u2013\u00a0at opposition<\/a>, for example \u2013 you should be able to spot it easily enough with a pair of binoculars, or through a small telescope.<\/p>\n

It\u2019s covered in ice<\/p>\n

The outer surface of Europa is made entirely of water ice. This gives it a very high albedo (i.e. it reflects a lot of sunlight) \u2013 which is another reason it\u2019s fairly easy for night-sky observers to locate.<\/p>\n

\"ImagesJupiter’s moon Europa captured by NASA’s Galileo spacecraft. Credit: NASA\/JPL\/DLR
\nLike Earth, Europa has an iron core<\/p>\n

At the heart of Europa lies an iron core. That\u2019s surrounded by mantle of magma \u2013 mostly silicate rock, which is where most of the satellite\u2019s mass comes from.<\/p>\n

So far, so Earth-like, but where Earth is wrapped in rocky crust, with oceans of water above, on Europa the crust is made of ice, with a vast liquid ocean below.<\/p>\n

The crust shows some evidence of plate tectonics<\/p>\n

The plates that make up Earth\u2019s rocky crust aren\u2019t fixed: one plate can slide over or under another, which is why we have earthquakes.<\/p>\n

Evidence suggests that the same thing may be happening at Europa, except in this case with giant plates of ice rather than rock.<\/p>\n

It has a young, smooth surface<\/p>\n

While Europa itself is around 4\u20134.5 billion years old (as is true of most large rocky objects in the Solar System), its surface is believed to be between 20 and 180 million years old.<\/p>\n

We can tell this from its lack of impact craters. In fact, Europa has the smoothest surface of any solid Solar System object.<\/p>\n

\"ImageImage of the surface of Jupiter’s mooon Europa captured by the Stellar Reference Unit on NASA’s Juno spacecraft, 29 September 2022. Top right can be seen double ridges and dark stains that could indicate plumes activity. Bottom right is a feature nicknamed the ‘Platypus’. Credit: NASA\/JPL-Caltech\/SwRI
\nEuropa orbits Jupiter once every 3.55 Earth days<\/p>\n

As the Galilean moon with the second-smallest orbital radius (670,900km\/416,878 miles), Europa whizzes around its host planet pretty speedily.<\/p>\n

Only Io, with an orbital radius of 421,800km (262,094 miles), has a shorter orbital period (1.77 Earth days).<\/p>\n

It\u2019s cold\u2026 very cold<\/p>\n

With an average temperature of \u2013160\u00b0C (\u2013267\u00b0F) at the equator and \u2013220\u00b0C (\u2013364\u00b0F) at the poles, Europa is extremely cold.<\/p>\n

It\u2019s far enough away that it receives 25 times less energy from the Sun than Earth does.<\/p>\n

Most of its energy comes from tidal heating<\/p>\n

Like many Solar System objects, Europa doesn\u2019t sit bolt upright relative to its orbital path \u2013 its axis is slightly tilted.<\/p>\n

And it has a slightly elliptical \u2013 or egg-shaped \u2013 orbit around Jupiter. This, combined with the gravitational pull of its fellow Galileo moons, means Europa is constantly engaged in a gravitational tug-of-war, being pushed and pulled as it orbits Jupiter.<\/p>\n

That generates tidal currents inside the planet\u2019s subsurface ocean and rocky mantle, which creates friction and so generates heat.<\/p>\n

\"Galileo'sGalileo’s drawings of Jupiter and moons from his seminal work Sidereus Nuncius.
\nEuropa was discovered by Galileo in 1610<\/p>\n

Galileo Galilei<\/a> famously discovered the four Galilean moons in early January 1610, although fellow astronomer Simon Marius is also believed to have spotted them around the same time.<\/p>\n

It\u2019s named after a lover of Zeus<\/p>\n

In Greek mythology, Europa was the daughter of the Phoenician king of Tyre.<\/p>\n

Zeus, entranced by her beauty, transformed himself into a white bull and in such guise lured her away to Crete, where she became queen and gave birth to King Minos.<\/p>\n

Oh, and Europe is named after her as well!<\/p>\n

It hasn\u2019t been known as Europa for very long<\/p>\n

Jupiter was the Roman equivalent of the Greek god Zeus, and so Simon Marius proposed naming the Galilean moons after lovers of Zeus soon after their discovery, apparently at the suggestion of Johannes Kepler<\/a>.<\/p>\n

But the idea never really caught on, and until the mid-20th century, Europa was more commonly known as Jupiter II.<\/p>\n

\"Jupiter'sJupiter’s four Galilean moons as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. Left to right: Io, Europa, Ganymede and Callisto. Credit: NASA\/Johns Hopkins University Applied Physics Laboratory\/Southwest Research Institute
\nEuropa is tidally locked to Jupiter<\/p>\n

In other words, the same face of Europa always faces Jupiter, just as the same face of our Moon always faces towards Earth<\/a>.<\/p>\n

This is, in fact, true of all large Solar System satellites: as a rule of thumb, if they\u2019re large enough to have become rounded by gravity, they\u2019re also tidally locked to their host planet.<\/p>\n

It has a thin, tenuous atmosphere<\/p>\n

Europa\u2019s atmosphere extends up to 190km (120 miles) above the surface and mostly consists of molecular oxygen.<\/p>\n

Radiation from Jupiter breaks down water ice at the surface into molecular oxygen and molecular hydrogen. The hydrogen, being lighter, dissipates into space, but the oxygen hangs around.<\/p>\n

There\u2019s still not enough of it for human beings to breathe there, though.<\/p>\n

\"IllustrationIllustration showing charged particles from Jupiter hitting Europa\u2019s surface, splitting frozen water molecules into oxygen and hydrogen. Could some of this oxygen be making its way into Europa’s subsurface ocean? Credit: NASA\/JPL-Caltech\/SWRI\/PU
\nEuropa is bombarded with radiation from Jupiter<\/p>\n

Jupiter has a magnetic field that\u2019s 20,000 times stronger than Earth\u2019s. This generates a huge amount of radiation, and Europa \u2013 being so close-in \u2013 receives a lot of that.<\/p>\n

If you spent a day on the surface of Europa, then \u2013 quite apart from the fact that you wouldn\u2019t be able to breathe, and would freeze to death \u2013 you\u2019d likely die from radiation exposure, or at least become very, very ill.<\/p>\n

It has no weather to speak of<\/p>\n

There are no winds on Europa. There are no clouds, there is no precipitation and its sky is completely colourless.<\/p>\n

There simply isn\u2019t enough of an atmosphere for such atmospheric phenomena to occur.<\/p>\n

There\u2019s much we don\u2019t know about its surface<\/p>\n

Although the Europan surface is relatively smooth and flat \u2013 there are very few craters and no tall mountains or deep valleys \u2013 it\u2019s not entirely featureless.<\/p>\n

Much of its surface is covered in large cracks (lineae) that form a criss-cross pattern, which is why some form of plate tectonics is believed to be at work.<\/p>\n

These cracks have a reddish hue, which has yet to be fully explained \u2013 some suggest the colour may denote high levels of magnesium sulphate, while others point to a type of organic compound known as tholins.<\/p>\n

There are also circular or elliptical features called lenticulae, which are thought to be domes or pits.<\/p>\n

\"Europa'sEuropa’s cracked surface, as seen by the Voyager 2 spacecraft, 9 July 1979. Credit: NASA\/JPL
\nThere are two competing theories regarding Europa’s crust<\/p>\n

The jury\u2019s out on the precise nature of Europa\u2019s crust, with \u2018thick ice\u2019 and \u2018thin ice\u2019 models vying for scientists\u2019 favour.<\/p>\n

The thick ice model suggests a crust thickness of 10-30km (6-20 miles) while the thin ice model says the crust should be just a few kilometres thick.<\/p>\n

Its icy crust rotates<\/p>\n

As Europa\u2019s subsurface ocean covers the entire surface, the icy crust that sits on top of it isn\u2019t bound to the rocky inner layers at all, and is free to rotate.<\/p>\n

In fact, scientists believe the crust may, since its formation, have rotated by as much as 80\u00b0, relative to the satellite\u2019s core.<\/p>\n

It may nor may not give off plumes of water<\/p>\n

In 2012, there was much excitement when images from the Hubble Space Telescope appeared to show plumes of liquid water erupting from the Europan surface and reaching a height of up to 200km (125 miles).<\/p>\n

And in 2018, scientists re-examined data from the earlier Galileo probe and found some evidence that the NASA craft may actually have flown through one of these plumes.<\/p>\n

However, a more recent study published in 2026 has called the existence of such plumes into question, after scientists failed to detect more than trace amounts of water vapour in Europa\u2019s atmosphere.<\/p>\n

If water was routinely gushing 200km up into the air, you\u2019d expect to find quite a lot of it.<\/p>\n

\"AA Hubble Space Telescope image of Europa showing suspected plumes of water vapour erupting at the 7 o’clock mark. Credits: NASA\/ESA\/W. Sparks (STScI)\/USGS Astrogeology Science Center
\nThere may be lakes of liquid water within the crust<\/p>\n

Lakes of liquid water that sit within the frozen crust \u2013 entirely separate from the subsurface ocean below it \u2013 are one possible explanation for the lenticulae observed on the surface.<\/p>\n

There may also be icy spikes at the equator<\/p>\n

Another moot point is the presence (or otherwise), at the Europan equator, of icy spikes called penitentes.<\/p>\n

These jagged, vertical features can be found at high altitudes here on Earth, and are caused by the action of solar radiation on ice.<\/p>\n

The Pioneer and Voyager missions both flew by briefly<\/p>\n

Pioneer 10 and 11 conducted flybys of Europa in 1973\/74, while the two Voyager missions passed by the satellite in 1979.<\/p>\n

The Pioneer craft sent back some very low-resolution images, while Voyager provided better imagery and, by way of detecting disruptions to Jupiter\u2019s magnetic field, our first evidence of Europa\u2019s subsurface ocean.<\/p>\n

\"TheThe first image of Europa from a spacecraft was captured by NASA’s Pioneer 10 mission. Credit: NASA\/JPL-Caltech
\nMost of what we know about Europa is thanks to the Galileo mission<\/p>\n

NASA\u2019s Galileo probe orbited Jupiter from 1995 until 2003 and made 12 close flybys of Europa during that time.<\/p>\n

Those flybys provided most of the concrete information that we have about Europa \u2013 indeed, the data it sent back from Europa so intrigued scientists that NASA extended the mission for two years to learn more.<\/p>\n

Two further missions have since visited<\/p>\n

NASA\u2019s New Horizons mission flew by Europa on its way to Pluto in 2007, while the Juno orbiter came within 352km (219 miles) of the Europan surface in 2022<\/p>\n

Two current missions should tell us a lot more<\/p>\n

The European Space Agency\u2019s Jupiter Icy Moons Explorer \u2013 or JUICE, for short \u2013 launched in 2023 and is expected to arrive at the Jovian system in 2031.<\/p>\n

Similarly, NASA\u2019s Europa Clipper launched in 2024, and is expected to arrive in 2030 \u2013 although Europa Clipper will not orbit or land on its namesake.<\/p>\n

Instead, it will orbit Jupiter, but conduct over 40 flybys of Europa while it\u2019s there.<\/p>\n

\"CracksCracks and ridges on Europa’s surface captured by NASA’s Galileo spacecraft on 2 February 1999. Credit: NASA\/JPL-Caltech\/Cynthia Phillips
\nEuropa is of great interest to astrobiologists<\/p>\n

There is a good reason why NASA and ESA are so keen to find out more about Europa \u2013 it\u2019s thought to be one of the most promising places in the Solar System to look for extraterrestrial life.<\/p>\n

That\u2019s largely because temperatures in the subsurface ocean can reach 0\u00b0C \u2013 still freezing, but positively balmy compared to most of the Solar System \u2013 and because of the large amounts of oxygen found in Europa\u2019s atmosphere.<\/p>\n

There is also some evidence, on the surface, of clay-like minerals that, on Earth, are associated with organic processes.<\/p>\n

But don\u2019t get too excited: if there\u2019s life there, it\u2019s likely to take the form of microorganisms, like bacteria here on Earth, rather than little green men!<\/p>\n

If it does have plumes, that\u2019s going to help a lot<\/p>\n

If the putative water plumes spouting from Europa\u2019s surface turn out to be real, that\u2019s going to be a major boon in the hunt for extraterrestrial life.<\/p>\n

That\u2019s because a probe could simply fly through such plumes to take samples and readings, rather than having to attempt to peer below, or drill into, Europa\u2019s icy crust.<\/p>\n

What are your favourite facts? Let us know by emailing contactus@skyatnightmagazine.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"At first glance, Jupiter\u2019s moon Europa might look less like a cradle for life and more like a…\n","protected":false},"author":2,"featured_media":545222,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[85,46,141,145],"class_list":["post-545221","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-il","tag-israel","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/545221","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=545221"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/545221\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/545222"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=545221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=545221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=545221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}