{"id":14723,"date":"2017-04-14T00:52:06","date_gmt":"2017-04-13T16:52:06","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/new-discoveries-raise-prospects-for-life-on-moons-of-jupiter-and-saturn\/"},"modified":"2017-04-14T00:52:06","modified_gmt":"2017-04-13T16:52:06","slug":"new-discoveries-raise-prospects-for-life-on-moons-of-jupiter-and-saturn","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/new-discoveries-raise-prospects-for-life-on-moons-of-jupiter-and-saturn\/","title":{"rendered":"New discoveries raise prospects for life on moons of Jupiter and Saturn"},"content":{"rendered":"
\"\"
This diagram of Saturn\u2019s moon Enceladus shows its interior structure, with an icy shell and a subsurface ocean of liquid water over a rocky core. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

Scientists announced Thursday that measurements from NASA\u2019s Cassini spacecraft detected hydrogen gas, a key energy source for microbial life, in a plume gushing from a vast liquid water ocean buried beneath the icy shell of Saturn\u2019s moon Enceladus.<\/p>\n

The hydrogen is coming from hydrothermal vents at the bottom of Enceladus\u2019s subsurface ocean, scientists said, similar to geologic features found deep underwater on Earth.<\/p>\n

\u201cThis is a very significant finding because the hydrogen could be a potential source of chemical energy for any microbes that might in be in Enceladus\u2019s ocean,\u201d said Linda Spilker, project scientist on the Cassini mission at NASA\u2019s Jet Propulsion Laboratory in Pasadena, California.<\/p>\n

Cassini measured the hydrogen during a high-speed pass through jets of ice and dust spewing from Enceladus\u2019s south pole in October 2015, the deepest dive through the plumes since the spacecraft found them them in 2005.<\/p>\n

The fountains erupt through fractures, dubbed tiger stripes, visible in the moon\u2019s icy crust.<\/p>\n

While Cassini does not have the instrumentation to directly confirm the presence of microbes in the ocean of Enceladus, the latest data from the space probe reinforces the notion that the icy moon of Saturn \u2014 one-seventh the size of Earth\u2019s moon \u2014 is one of the best places to look for extraterrestrial life in the solar system.<\/p>\n

Researchers also presented new evidence that Jupiter\u2019s moon Europa \u2014 more than six times bigger than Enceladus \u2014 could have periodic eruptions similar to ones coming from Saturn\u2019s moon.<\/p>\n

William Sparks, an astronomer who analyzed imagery from the Hubble Space Telescope, said his research team has linked the location of a likely plume found by Hubble with thermal maps from NASA\u2019s Galileo spacecraft, which orbited Jupiter and made repeated flybys of Europa in the late 1990s and early 2000s.<\/p>\n

It turns out the plume near Europa\u2019s equator is at the same location of a hotspot identified by Galileo, said Sparks, who works at the Space Telescope Science Institute in Baltimore, Maryland.<\/p>\n

The latest Hubble imagery builds on previous observations in 2012 and 2014 that suggested Europa might have intermittent plumes streaming as high as 60 miles \u2014 100 kilometers \u2014 above its surface.<\/p>\n

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These composite images show a suspected plume of material erupting two years apart from the same location on Jupiter\u2019s icy moon Europa. Both plumes, photographed in UV light by Hubble, were seen in silhouette as the moon passed in front of Jupiter. Credit: NASA\/ESA\/STScI\/USGS<\/figcaption><\/figure>\n

\u201cIn 2014, we used the Hubble (telescope) and detected evidence of what are probably water vapor plumes emerging form the surface of Europa,\u201d Sparks said. \u201cThat\u2019s important because it could be giving us access to subsurface liquid water without having to drill through miles of ice.<\/p>\n

\u201cIn 2016, the new observations that we\u2019re just publishing, we saw a similar candidate almost identical in appearance, and at the identical location, to one of the 2014 candidates,\u201d Sparks said. \u201cIt\u2019s very important in an intermittent phenomenon to establish repeatabilty. It gives us a lot more faith in the observation.\u201d<\/p>\n

\u201cThe plumes of Enceladus are associated with a heat source, and its very distinctive signature, so we looked to see if we could find thermal imaging of the surface of Europa, and we did,\u201d Sparks said. \u201cThe peak hottest point on the Europa night side is right where our plume candidate is.\u201d<\/p>\n

The strong tug of gravity from Jupiter and Saturn is responsible for the churning and heating inside Europa and Enceladus that maintain their liquid water oceans.<\/p>\n

With the discovery from Cassini announced Wednesday, scientists know Enceladus has the water and chemicals needed to support life, according to Mary Voytek, a senior scientist in astrobiology at NASA Headquarters in Washington.<\/p>\n

\u201cCertainly, this finding suggests that there is a significant amount of hydrothermal activity to produce such a strong signal of hydrogen, and this hydrogen is a good source of chemical energy to support life,\u201d Voytek said.<\/p>\n

Cassini\u2019s ion and neutral mass spectrometer identified molecular hydrogen as Cassini zipped through the plumes at around 19,000 mph (8.5 kilometers per second). Researchers were eager to make the hydrogen detection, knowing such a finding would bolster the chances that life may lurk hidden beneath Enceladus\u2019s icy shell.<\/p>\n

\u201cThis sampling is extremely important for detecting trace species, and we were able to, from the previous flybys and previous measurements, find out that the plume is 98 percent water,\u201d said Hunter Waite, head of the ion and neutral mass spectrometer team at the Southwest Research Institute in San Antonio. \u201cIt has traces of ammonia, carbon dioxide, and methane, as well as some organics. The part that had been elusive to us before was the hydrogen.\u201d<\/p>\n

Waite is lead author of a paper in the journal Science outlining the hydrogen discovery.<\/p>\n

\"\"
This graphic illustrates how Cassini scientists think water interacts with rock at the bottom of the ocean of Saturn\u2019s icy moon Enceladus, producing hydrogen gas.
Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

The hydrogen is made in a chemical reaction between warm water, carbon dioxide and rock at Enceladus\u2019s seafloor, a geochemical process called serpentinization found in hydrothermal vents at the bottoms of Earth\u2019s oceans.<\/p>\n

Like the vents in terrestrial oceans, hydrothermal environments on Enceladus \u2014 a billion miles farther from the sun than Earth \u2014 are starved of sunlight, and any life forms that took hold there would have evolved to seek an alternative source of energy, like hydrogen.<\/p>\n

\u201cThese vents on the Earth support teeming communities of organisms anchored by microbes that feed on chemical energy rather than sunlight,\u201d said Chris Glein, a research scientist working on the Cassini mission at the Southwest Research Institute. \u201cAn important reaction at the base of the food chain is called methanogenesis. This is where microbes combine hydrogen with carbon dioxide to make methane, and they get a jolt of energy out of the process.\u201d<\/p>\n

Scientists calculated the energy available to potential alien microbes living in Enceladus as roughly equivalent to 300 pizzas per hour, according to Glein.<\/p>\n

\u201cWe have made the first calorie count in an alien ocean,\u201d Glein said. \u201cThis is a key step towards understanding the habitability of Enceladus.\u201d<\/p>\n

\u201cIf, indeed, there\u2019s life in there, it has to be completely different than ours, in the sense that it\u2019s generated in a way that\u2019s not related to our life,\u201d said Jim Green, head of NASA\u2019s planetary science division. \u201cWe call that a second genesis.\u201d<\/p>\n

Conceived in the 1980s and built in the 1990s, the Cassini spacecraft was not designed to search for life at Enceladus. The mass spectrometer that made the hydrogen detection at Enceladus was originally intended to sample the atmosphere of Titan, Saturn\u2019s largest moon, but managers repurposed the instrument to examine the icy moon\u2019s polar plumes after Cassini discovered the geysers streaming into space in 2005, soon after the probe arrived in orbit around the ringed planet.<\/p>\n

\u201cThis finding is the result of 12 years of Cassini investigations, and it really represents a capstone finding of the mission because we now know that Enceladus has almost all of the ingredients that you would need to support life as we know it on Earth,\u201d Spilker said.<\/p>\n

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The enhanced color view of Enceladus comes from NASA\u2019s Cassini spacecraft. The moon\u2019s bluish tiger stripes are visible at the bottom of the image. Credit: NASA\/JPL\/Space Science Institute<\/figcaption><\/figure>\n

Cassini is in the final year of its mission, heading for a plunge into Saturn\u2019s atmosphere Sept. 15 after a series of passages between the planet\u2019s cloud tops and rings set to begin later this month.<\/p>\n

The plutonium-powered spacecraft will not fly by Enceladus again, and a final swing by Titan on April 22 will use the moon\u2019s gravity to reshape Cassini\u2019s orbit to fly inside Saturn\u2019s rings.<\/p>\n

Launched in 1997, Cassini is running low on fuel, and officials want to ensure it does not crash into moons like Enceladus that could harbor life. NASA decided in 2010 to steer Cassini into Saturn, destroying the spacecraft to avoid plowing into the habitable moons while capturing unprecedented data on the planet\u2019s rings and atmosphere.<\/p>\n

\u201cWhen Cassini was first built, we never thought we would see an active ocean world like Enceladus at Saturn,\u201d Spilker said. \u201cSo Cassini can look for habitability, but we don\u2019t have the instruments to look for life. We\u2019ve come as far as we can go, so it remains for a future mission to detect life at Enceladus.\u201d<\/p>\n

NASA has no more missions to Saturn on the books, but scientists are finalizing proposals for new interplanetary robotic probes to be submitted to the space agency by April 28.<\/p>\n

The competition is for the next mission in NASA\u2019s New Frontiers program, a set of medium-cost planetary missions that has so far included the New Horizons probe that flew by Pluto in 2015, the Juno spacecraft now orbiting Jupiter and the OSIRIS-REx asteroid sample return mission that launched in September 2016.<\/p>\n

Senior NASA officials will select one mission from the New Frontiers proposals for full funding in mid-2019, with a launch targeted by the end of 2025.<\/p>\n

NASA has restricted the types of missions eligible for the next New Frontiers selection, including concepts to explore Enceladus and Titan.<\/p>\n

Other candidates are a comet surface sample return mission, a project to extract and return specimens from a basin near the lunar south pole, a mission to investigate the atmosphere of Saturn, a spacecraft to visit the Trojan asteroids sharing an orbit with Jupiter, and a probe to study the atmosphere and surface of Venus.<\/p>\n

Scientists believe Enceladus, with its constant eruptions, is an easier target to look for the existence of life. A mission with the right sensor package could fly through the plumes and search for materials like amino acids and other biosignatures thrown into space from Enceladus\u2019s ocean.<\/p>\n

For Europa, with its supposed intermittent plumes and an ocean containing twice the water in all of Earth\u2019s seas, looking for life is more tricky and may require a lander.<\/p>\n

\u201cIf we\u2019ve got a salty ocean in contact with a rocky core and energy from a variety of sources \u2026 We have many of the ingredients thought to be necessary for life,\u201d said Sparks.<\/p>\n

NASA has officially approved development of a sophisticated flyby craft named Europa Clipper to make dozens of close approaches with Jupiter\u2019s icy moon at altitudes as low as 16 miles (25 kilometers). Europa Clipper is set for launch as soon as 2022 and could arrive in Jupiter\u2019s neighborhood in the late 2020s.<\/p>\n

A team of scientists and engineers at the Jet Propulsion Laboratory is also designing a robot lander that could touch down on Europa in the early 2030s, assuming Congress funds the mission.<\/p>\n

Voytek said Enceladus is thought to be younger than Europa, and the levels of hydrogen detected by Cassini mean a lot of energy is not being consumed by potential organisms living in the moon\u2019s ocean, raising questions about whether microbes actually exist there.<\/p>\n

According to Voytek, Europa may be the better candidate for life if it has the same types of hydrothermal activity as Enceladus. \u201cThere\u2019s no reason to think it wouldn\u2019t be happening on Europa,\u201d she said.<\/p>\n

\u201cWe know that Europa and the moons around Jupiter were formed 4 billion years ago,\u201d Voytek said. \u201cThat\u2019s a lot more time for life to have emerged and start taking advantage of these energy sources.<\/p>\n

\u201cSo my money, for the moment, is still on Europa, but (life) could be on any of these moons, and certainly it would be great if it was on all of them.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

This diagram of Saturn\u2019s moon Enceladus shows its interior structure, with an icy shell and a subsurface ocean of liquid water over a rocky core. Credit: NASA\/JPL-Caltech Scientists announced Thursday that measurements from NASA\u2019s Cassini spacecraft detected hydrogen gas, a key energy source for microbial life, in a plume gushing from a vast liquid water […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1874,2394,1559,1659,1282,898,1183,1606],"class_list":["post-14723","post","type-post","status-publish","format-standard","hentry","category-news","tag-astrobiology","tag-cassini","tag-enceladus","tag-europa","tag-europa-clipper","tag-hubble-space-telescope","tag-jet-propulsion-laboratory","tag-jupiter"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14723"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=14723"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14723\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=14723"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=14723"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=14723"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}