Image credit: NASA/JPL-CaltechCould we go fishing on a planet-sized frozen moon near JupiterUsing cutting-edge 3D modeling techniques unheard of last century, NASA scientists have re-examined 21-year-old data of Europa, one of Jupiters moons known to have a huge, salty, liquid ocean underneath its icy surface.They found new evidence to back-up astronomers suspicions that Europa is spewing water vapor into space.If its ocean does host simple life, that means a spacecraft could sniff it and, potentially, discover signs of life.Go sniff a moonThe data were there, but we needed sophisticated modeling to make sense of the observation, said Xianzhe Jia, a space physicist at the University of Michigan in Ann Arbor whose team has been re-examining data from the Galileo space probe that reached Jupiter in 1997.
Europa as seen by the Galileo spacecraft in the late 1990s | Credit: NASA/JPL-Caltech/SETI InstituteBack in 2012, the Hubble Space Telescope found evidence of water vapor vents off Europa's south pole, and did again soon after.We were inspired by those Hubble detections, and realized that one of Galileos flybys of Europa was just 124 miles above the region that Hubble saw repeated plumes, said Jia.
We needed to see whether there was anything in the data that could tell us whether or not there was a plume.Old data, new discoveriesEuropas plumes are likely fed by a subsurface water ocean, or pockets of ocean, under Europa's crust, so a future spacecraft could flyby and investigate their chemical makeup.That's what NASA wants to do with its Europa Clipper mission; go sniff a moon.
With this new re-examining of old data, NASA can be sure the mission is worth it.This is not the first time that Galileo's data has been re-visited.
NASA researchers have also reviewed historical data collected by Galileo to get closer to discovering why Jupiters moon Ganymede the solar systems largest moon has such a bright aurora.What is NASA planning to do at EuropaWhat Hubble and, it seems, also Galileo found on Europa has tantalized planetary scientists, and momentum has since built up for a dedicated mission.Called the Europa Clipper, NASA's spacecraft will conduct approximately 45 flybys of the icy moon during a three- or four-year mission.
Some of those flybys would get as close as 16 miles from Europa's surface.Europa is strewn with cracks and ridges | Credit: NASA/JPL/University of Arizona(Image: NASA/JPL/University of Arizona)This is about the search for the ingredients for life.
Life as we know it and that's all we know requires three things: liquid water, the right chemistry, and an energy source to drive biology.The Europa Clipper will confirm whether the moon has that subsurface ocean, and search for signs of the other two criteria.So, the spacecraft will image the moon's icy surface in high resolution and examine the composition and the structure of its interior and icy covering using two ice-penetrating radar antennas.What is Europa likeEuropa is cold, cracked and chaotic.
As cold as -370 F/-220 C at its poles, it's covered in water ice and frozen sulfur dioxide, and it's thought that underneath is a liquid salty ocean.If that does exist, it probably moves a lot because Europa's ice surges up and down by 50 metres thanks to the gravitational pull of Jupiter.Europa isn't the only moon in the solar system to have the potential to host life.
In 2005, NASAs Cassini spacecraft discovered jets of water vapor and dust spewing off the surface of Saturns moon Enceladus.When will Europa Clipper arriveThat depends when it launches, and on what kind of rocket.
Its tentatively scheduled to launch in 2022, but the politics are messy.The mission must be as cheap as possible and launch on time, which means using a SpaceX Falcon Heavy rocket is a no-brainer.Except that, unless the Europa Clipper uses NASAs own flagship Space Launch System (SLS) uber-rocket which is overdue, over budget, misunderstood by politicians, and likely to delay the Europa Clippers launch until 2025 Congress might cancel the SLS.The Europa Clipper will discover if there are the ingredients necessary to support life | Credit: NASA/JPL-CaltechThe politics are complex, but suffice to say, the preparation for this mission is likely to be just as much about NASAs future as it is the search for alien life.The mid-to-late 2020s is all we know about the Europa Clippers arrival date, because which rocket it launches on will determine how long it takes to get there.Are there any other missions to Europa plannedPlanned to launch in 2022, the European Space Agency's Jupiter Icy Moons Explorer (JuICE) will spend three and a half years examining Europa, Ganymede and a third moon, Callisto, all of which are thought to conceal oceans of liquid water beneath their icy crusts.The JuICE mission will explore Europa, Ganymede and Callisto | Credit: ESA/ATG medialabJuICE will carry cameras and ice-penetrating radar, among other instruments, and detect organic molecules.At Europa, it will explore its active regions and study the composition of the icy crust, detecting whether there are shallow reservoirs of water sandwiched between icy layers.How to see Europa in the night skyIt may only be the sixth-largest moon in the solar system, but Europa is a relatively easy object to see in the night sky.Jupiter has 53 moons in total, but the biggest four Io, Europa, Ganymede, and Callisto are known as the Galilean moons.First spotted by Italian astronomer Galileo Galilei through a small telescope in 1610, absolutely any size of scope pointed at Jupiter will reveal them.Europa and the other Galilean moons are easy to see with a small telescope | Credit: NASAThey can also be seen through high-powered binoculars.
Now is a great time to do so because Jupiter is at opposition Earth is directly between the sun and the giant planet making Jupiter the brightest its been for 13 months and, technically, since 2002.So, who will get to Europa first, NASAs Europa Clipper or the ESAs JuICEThough the launch schedule and thus the speed of the Europa Clipper is up in the air, the set-in-stone ESAs JuICE is solar-powered, so it will take seven years to reach the Jovian System.The hunt for alien life is nothing if not a slow-burner, but at least now astronomers know that Europas has plumes; the solar system sniff is on.VKbNCkprWLDKr9RoyNRZKJ.jpg#