On Oct. 14, 2024, NASA launched a robotic spacecraft named Europa Clipperto Jupiter’s moons. Clipper will attain the ice-covered Jovian moon Europa in 2030 and spend a number of years accumulating and sending invaluable knowledge on the moon’s potential habitability again to Earth.
Clipper isn’t the one mission highlighting researchers’ curiosity in Jupiter and its moons.
On April 13, 2023, the European House Company launched a rocket carrying a spacecraft destined for Jupiter. The Jupiter Icy Moons Explorer– or JUICE – will spend not less than three years on Jupiter’s moons after it arrives in 2031.
I’m a planetary scientist who research the construction and evolution of stable planets and moons within the photo voltaic system.
There are numerous causes my colleagues and I are trying ahead to getting the info that Europa Clipper and JUICE will hopefully be sending again to Earth within the 2030s. However maybe probably the most thrilling info should do with water. Three of Jupiter’s moons – Europa, Ganymede, and Callisto – are house to giant, underground oceans of liquid water that might assist life.
This composite picture reveals, from high to backside, Io, Europa, Ganymede and Callisto subsequent to Jupiter. NASA, CC BY-ND
Meet Io, Europa, Ganymede and Callisto
Jupiter has dozens of moons. 4 of them, particularly, are of curiosity to planetary scientists.
Io, Europa, Ganymede, and Callisto are, like Earth’s Moon, comparatively giant, spherical, advanced worlds. Two earlier NASA missions have despatched spacecraft to orbit the Jupiter system and picked up knowledge on these moons. The Galileo mission orbited Jupiter from 1995 to 2003 and led to geological discoveries on all 4 giant moons. The Juno mission continues to be orbiting Jupiter right now and has supplied scientists with an unprecedented view into Jupiter’s composition, construction, and house atmosphere.
These missions and different observations revealed that Io, the closest of the 4 to its host planet, is abuzz withgeological exercise, together with lava lakes, volcanic eruptions, and tectonically shaped mountains. However it’s not house to giant quantities of water.
Europa, Ganymede, and Callisto, in distinction, have icy landscapes. Europa’s floor is a frozen wonderland with a younger however advanced historical past, probably together with icy analogs of plate tectonics and volcanoes. Ganymede, the most important moon in the whole photo voltaic system, is greater than Mercury and has its personal magnetic area generated internally from a liquid metallic core. Callisto seems considerably inert in comparison with the others however serves as a invaluable time capsule of an historical previous that’s not accessible on the youthful surfaces of Europa and Io.
Most fun of all, Europa, Ganymede, and Callisto all virtually definitely possess underground oceans of liquid water.
Heat from Europa’s inside and tidal power from Jupiter doubtless keep a large liquid ocean beneath the moon’s icy floor. NASA/JPL-Caltech/Michael Carroll
Ocean Worlds
Europa, Ganymede, and Callisto have chilly surfaces which are lots of of levels under zero. At these temperatures, ice behaves like stable rock.
However similar to Earth, the deeper underground you go on these moons, the warmer it will get. Go down far sufficient, and you ultimately attain the temperature the place ice melts into water. Precisely how far down this transition happens on every of the moons is a topic of debate that scientists hope to resolve with JUICE and Europa Clipper. Whereas the precise depths are nonetheless unsure, scientists are assured that these oceans exist.
The very best proof of those oceans comes from Jupiter’s magnetic area. Saltwater is electrically conductive. So, as these moons journey by Jupiter’s magnetic area, they generate a secondary, smaller magnetic area that alerts to researchers the presence of an underground ocean. Utilizing this system, planetary scientists have been capable of present that the three moons comprise underground oceans. And these oceans aren’t small – Europa’s ocean alone might need greater than double the water of all of Earth’s oceans mixed.
An apparent and tantalizing subsequent query is whether or not these oceans can assist extraterrestrial life. Liquid water is a vital a part of what makes for a liveable world, however it’s removed from the one requirement for all times. Life additionally wants power and sure chemical compounds, along with water, to flourish. As a result of these oceans are hidden beneath miles of stable ice, daylight and photosynthesis are out. However it’s potential different sources may present the wanted substances.
On Europa, for instance, the liquid water ocean overlays a rocky inside. That rocky seafloor may present power and chemical compounds by underwater volcanoes that might make Europa’s ocean liveable. However it’s also potential that Europa’s ocean is a sterile, inhospitable place – scientists want extra knowledge to reply these questions.
The Jupiter Icy Moons Explorer spacecraft will journey for eight years earlier than reaching Jupiter. ESA/ATG medialab/NASA/JPL/College of Arizona/J. Nichols
Upcoming Missions from ESA and NASA
Europa Clipper and JUICE are set as much as give scientists game-changing details about the potential habitability of Jupiter’s moons. Whereas each missions will collect knowledge on a number of moons, JUICE will spend time orbiting and specializing in Ganymede, and Europa Clipper will make dozens of shut flybys of Europa.
Each of the spacecraft will carry a set of scientific devices constructed particularly to research the oceans. Onboard radar will permit Europa Clipper and JUICE to probe into the moons’outer layers of stable ice. Radar may reveal any small pockets of liquid water within the ice or, within the case of Europa, which has a thinner outer ice layer than Ganymede and Callisto, hopefully detect the bigger ocean.
Magnetometers can even be on each missions. These instruments will give scientists the chance to check the secondary magnetic fields produced by the interplay of conductive oceans with Jupiter’s area in nice element and can hopefully give researchers clues to salinity and volumes of the oceans.
Scientists can even observe small variations within the moons’ gravitational pulls by monitoring delicate actions in each spacecrafts’ orbits, which may assist decide if Europa’s seafloor has volcanoes that present the wanted power and chemistry for the ocean to assist life.
Lastly, each crafts will carry a bunch of cameras and light-weight sensors that may present unprecedented photographs of the geology and composition of the moon’s icy surfaces.
Possibly in the future, a spacecraft will be capable to drill by the miles of stable ice on Europa, Ganymede or Callisto and discover oceans immediately. Till then, observations from spacecraft like Europa Clipper and JUICE are scientists’ finest wager for studying about these ocean worlds.
When Galileo found these moons in 1609, they had been the primary objects identified to orbit one other planet immediately. Their discovery was the ultimate nail within the coffin of the speculation that Earth – and humanity – resides on the heart of the universe. Possibly these worlds have one other humbling shock in retailer.
This text, initially printed April 10, 2023, has been up to date with particulars concerning the Europa Clipper launch.
Mike Sori is an Assistant Professor of Planetary Science at Purdue College. This text is republished from The Dialog beneath a Inventive Commons license. Learn the unique article.
