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posted by n1 on Friday April 14 2017, @04:11PM   Printer-friendly

At a NASA press conference on Thursday, scientists from the Jet Propulsion Laboratory, NASA's D.C. Headquarters, and the Space Telescope Science Institute announced new observations about the "ocean worlds" Enceladus and Europa. At Enceladus, one of Saturn's moons, the Cassini spacecraft has measured emissions of hydrogen gas that could indicate a source of chemical energy for life forms. 2016 Hubble observations of Jupiter's moon Europa have found evidence of a water plume emanating from the same location as a plume measured in 2014.

The Cassini spacecraft took a "deep dive" into one of the Enceladus plumes on Oct. 28, 2015. The plume contains about 98% water, 0.4-1.4% hydrogen, and a mixture of carbon dioxide, methane, ammonia, and other molecules. The findings support the conclusion of hot water interacting with rock at hydrothermal vents on the seafloor, a type of habitat known to support life without the need for sunlight. NASA scientists have concluded that Enceladus has all of the conditions and ingredients necessary to support life, although the detection of hydrogen gas does not prove that the internal ocean currently contains life forms, and phosphorus and sulfur have yet to be measured.

The new Hubble images of Europa show that the height of the plume is about twice that of the one measured in 2014. The location of this periodic plume corresponds with a thermal hotspot on Europa's surface found by the Galileo spacecraft in the 1990s, which was once dismissed as an anomaly. The lack of craters on Europa's surface indicates that water is spraying out of the internal ocean through cracks and reshaping the surface. However, Europa's ice shell is thought to be thicker than that of Enceladus, with water vapor escaping the crust less often. NASA is currently developing a Europa Clipper mission that would conduct a series of 45 or more flybys of Europa, with the possibility of flying directly through water vapor plumes for sampling. The European Space Agency's Jupiter Icy Moons Explorer will study Europa and Callisto, but end its mission by orbiting Ganymede.

The same chemistry detected at Enceladus could also be taking place in interior oceans on other icy worlds, such as Ceres, Titan, Ganymede, Callisto, Dione, Rhea, Titania, Triton, Pluto, Eris, Sedna, etc.

Here's the press briefing (48m16s). Also at Science Magazine, BBC,, and Popular Mechanics (mhajicek's link).

Cassini finds molecular hydrogen in the Enceladus plume: Evidence for hydrothermal processes (open, DOI: 10.1126/science.aai8703) (DX)

Active Cryovolcanism on Europa? (DOI: 10.3847/2041-8213/aa67f8) (DX)

Original Submission #1Original Submission #2

Related Stories

Underground Ocean on Enceladus May be Close to the Surface 7 comments

Data collected by the Cassini spacecraft during a 2011 flyby of Saturn's moon Enceladus suggests that an internal liquid ocean may be closer to the surface than previously thought. Ice near the south pole of Enceladus, where plumes of water vapor have been detected, was found to be up to 20 K warmer than expected:

"These observations provide a unique insight into what is going on beneath the surface. They show that the first few metres below the surface of the area that we investigated, although at a glacial 50-60 K, are much warmer than we had expected: likely up to 20 K warmer in some places," [Alice Le Gall] adds. "This cannot be explained only as a result of the Sun's illumination and, to a lesser extent, Saturn's heating so there must be an additional source of heat."

The detected heat appears to be lying under a much colder layer of frost, as no similar anomaly was found in infrared observations of the same region – these probe the temperature of the surface but are not sensitive to what is underneath. [...] Even if the observations cover only a small patch of the southern polar terrains, it is likely that the entire region is warm underneath and Enceladus' ocean could be a mere 2 km under the icy surface. The finding agrees well with the results of a recent study, led by Ondrej Cadek [DOI: 10.1002/2016GL068634] and published in 2016, which estimated the thickness of the crust on Enceladus. With an average depth of 18–22 km, the ice shell appears to reduce to less than 5 km at the south pole.

Thermally anomalous features in the subsurface of Enceladus's south polar terrain (open, DOI: 10.1038/s41550-017-0063) (DX)

Original Submission

Cassini Spacecraft Post-Mortem 4 comments

Timeline of Cassini–Huygens

NASA's Cassini Spacecraft Ends Its Historic Exploration of Saturn

Telemetry received during the plunge indicates that, as expected, Cassini entered Saturn's atmosphere with its thrusters firing to maintain stability, as it sent back a unique final set of science observations. Loss of contact with the Cassini spacecraft occurred at 7:55 a.m. EDT (4:55 a.m. PDT), with the signal received by NASA's Deep Space Network antenna complex in Canberra, Australia.

[...] As planned, data from eight of Cassini's science instruments was beamed back to Earth. Mission scientists will examine the spacecraft's final observations in the coming weeks for new insights about Saturn, including hints about the planet's formation and evolution, and processes occurring in its atmosphere.

[...] Cassini launched in 1997 from Cape Canaveral Air Force Station in Florida and arrived at Saturn in 2004. NASA extended its mission twice – first for two years, and then for seven more. The second mission extension provided dozens of flybys of the planet's icy moons, using the spacecraft's remaining rocket propellant along the way. Cassini finished its tour of the Saturn system with its Grand Finale, capped by Friday's intentional plunge into the planet to ensure Saturn's moons – particularly Enceladus, with its subsurface ocean and signs of hydrothermal activity – remain pristine for future exploration.

Farewell, Cassini: a 20 year mission to Saturn comes to a life-protecting end

During the Jovian flyby, Cassini performed scientific observations of the planet, showing that Jupiter's cloud belts were areas of "net-rising atmospheric motion."

This observation contradicted previous hypotheses about Jupiter's dark and light belts and served to highlight differences in planetary weather systems.

During the flyby, Cassini was also able to study Jupiter's thin ring system, revealing that Jupiter's rings were composed of irregularly shaped particles that likely originated as ejecta from micrometeorite impacts with the moons Metis and Adrastea.

Cassini: The legend and legacy of one of NASA's most prolific missions


Porous Core Could be Keeping Enceladus Warm 3 comments

A study has found that a "porous"/sandy/muddy core can increase the energy released by gravitational tidal friction inside Saturn's moon Enceladus. This could explain why the interior of the icy moon has not cooled down after billions of years:

A paper published in Nature Astronomy today presents the first concept that explains the key characteristics of 500 km-diameter Enceladus as observed by the international Cassini spacecraft over the course of its mission, which concluded in September.

This includes a global salty ocean below an ice shell with an average thickness of 20–25 km, thinning to just 1–5 km over the south polar region. There, jets of water vapour and icy grains are launched through fissures in the ice. The composition of the ejected material measured by Cassini included salts and silica dust, suggesting they form through hot water – at least 90ºC – interacting with rock in the porous core.

These observations require a huge source of heat, about 100 times more than is expected to be generated by the natural decay of radioactive elements in rocks in its core, as well as a means of focusing activity at the south pole.

The tidal effect from Saturn is thought to be at the origin of the eruptions deforming the icy shell by push-pull motions as the moon follows an elliptical path around the giant planet. But the energy produced by tidal friction in the ice, by itself, would be too weak to counterbalance the heat loss seen from the ocean – the globe would freeze within 30 million years.

[...] In the new simulations the core is made of unconsolidated, easily deformable, porous rock that water can easily permeate. As such, cool liquid water from the ocean can seep into the core and gradually heat up through tidal friction between sliding rock fragments, as it gets deeper.

Powering prolonged hydrothermal activity inside Enceladus (DOI: 10.1038/s41550-017-0289-8) (DX)

Previously: Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Cassini Finds Evidence of Change in Enceladus's Spin Axis
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life

Original Submission

Yuri Milner Considering Privately Funded Mission to Enceladus 6 comments

Yuri Milner, the Russian billionaire backer of Breakthrough Initiatives and Breakthrough Prizes, has set his sights on Saturn's moon Enceladus:

Milner founded the $100 million Breakthrough Starshot project, an attempt to send small probes to Alpha Centauri. Now, he has announced plans to explore funding a mission to Enceladus.

[...] "Can we design a low-cost, privately funded mission to Enceladus which can be launched relatively soon, and that can look more thoroughly at those plumes, try to see what's going on there?" Milner asked the New Space Age conference in Seattle this week.

A probe to Enceladus could be done for well under $1 billion, but it likely wouldn't be able to drill through the icy surface.

The Cassini spacecraft already flew as close as 49 km above the surface of Enceladus, and flew through a plume of water vapor released by the satellite. A proposed mission such as the Enceladus Life Finder could repeatedly fly through plumes and use better sensors to attempt to detect evidence of organic materials or microbes.

Two upcoming missions will be studying Jupiter's moon Europa: the ESA's Jupiter Icy Moons Explorer and NASA's Europa Clipper. Europa is easier for spacecraft to reach than Enceladus, but has thicker ice blocking its internal ocean.

Also at Newsweek.

Related: NASA Releases Europa Lander Study 2016 Report
Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life
Cassini Spacecraft Post-Mortem
Porous Core Could be Keeping Enceladus Warm

Original Submission

Complex Organic Molecules Found on Enceladus 4 comments

Saturn moon a step closer to hosting life

Scientists have found complex carbon-based molecules in the waters of Saturn's moon Enceladus.

Compounds like this have only previously been found on Earth, and in some meteorites. They are thought to have formed in reactions between water and warm rock at the base of the moon's subsurface ocean.

Though not a sign of life, their presence suggests Enceladus could play host to living organisms. The discovery came from data gathered by the Cassini spacecraft.

Also at SwRI, ScienceAlert,, National Geographic, Popular Mechanics, and The Guardian.

Macromolecular organic compounds from the depths of Enceladus (DOI: 10.1038/s41586-018-0246-4) (DX)

Related: Minerals In Plumes of Enceladus Indicate Hydrothermal Activity
Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life
Cassini Spacecraft Post-Mortem
Porous Core Could be Keeping Enceladus Warm
Yuri Milner Considering Privately Funded Mission to Enceladus
Organic Molecules Found on Ceres
NASA Finds Evidence of Water Plume on Europa
Organic Matter Found on Mars
Study Finds Evidence of More Organic Material on Ceres

Original Submission

NASA Will Support Initial Concept Studies for Privately Funded Mission to Enceladus 4 comments

NASA to support initial studies of privately funded Enceladus mission

NASA signed an agreement in September with a foundation to support initial studies of a privately funded mission to a potentially habitable moon of Saturn. The unfunded Space Act Agreement between NASA and the Breakthrough Prize Foundation, initiated with little public fanfare, covers NASA support for initial concept studies, known in NASA programmatic parlance as "Pre-Phase A," for a mission to the moon Enceladus, an icy world believed to have a subsurface ocean of liquid water and plumes that eject that water through the surface into space.

The agreement, the seven-page document posted on a NASA website states, "shall be for the purpose of cooperating on the Breakthrough Pre-Phase A activities for Breakthrough's Enceladus Mission." That includes supporting a series of reviews that leads up to what NASA calls Key Decision Point (KDP) A, "to determine progress to Phase A, for further formation of the Enceladus Mission's concept and technology development."

[...] Most of the study work would be done by Breakthrough. NASA, under the agreement, would use "reasonable efforts" to offer scientific and technical consulting for the study, including expertise in a range of scientific fields and in planetary projection. NASA will also advise "in the development of Phase A plans for a life signature mission to Enceladus." The agreement between NASA and Breakthrough involves no exchange of funds. NASA estimates its cost of carrying out its responsibilities under the agreement to be $72,384.

The agreement, first reported by New Scientist, offers few details about the proposed mission itself. A companion document for the agreement notes that the foundation's Breakthrough Watch program "seeks to evaluate near-term missions to objects in the Solar System, including Enceladus," that would search for signs of life there. "The Enceladus Mission is considering novel low-cost approaches, one of which uses solar sail technology to flyby the moon of Saturn to collect scientific data.

However, foundation officials have publicly discussed their interest in an Enceladus mission for a year. "We formed a little workshop around this idea," said Yuri Milner, the Russian billionaire who funds the foundation, at an event in Seattle in November 2017. "Can we design a low-cost privately-funded mission to Enceladus, which can be launched relatively soon and that can look more thoroughly at those plumes to try to see what's going on there?"

Also at

Previously: Yuri Milner Considering Privately Funded Mission to Enceladus

Related: Underground Ocean on Enceladus May be Close to the Surface
Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life
Porous Core Could be Keeping Enceladus Warm
Complex Organic Molecules Found on Enceladus

Original Submission

Research Supports the Possibility of Geothermal Vents on Europa 11 comments

Europa volcanism & interior heating modeled in detail, offers research targets for upcoming missions

Europa, an icy Jovian moon that likely possesses an ocean beneath its icy crust, may have an interior that is hot enough to produce volcanic activity on its seafloor. New research provides evidence that this seafloor volcanism likely occurred in the moon's past and [may be] ongoing at present as well.

The team of researchers, led by Dr. Marie Běhounková of Charles University in the Czech Republic, developed their own 3D models of Europa's interior and heating transfer properties to investigate the possibility of volcanism on Europa's ocean floor given other volcanism seen in the Jovian system.

[...] These volcanoes would form due to the melting of Europa's interior and heat transfer from the rocky interior of Europa to the seafloor. Models developed by Běhounková et al. show that many different factors — including radiogenic power and tidal forces — contribute to the melting of the icy moon's interior.

[...] A Laplace resonance is a phenomenon that occurs when three planetary bodies with an orbital period ratio of 1:2:4 exert regular and periodic gravitational effects on each other. These nudges create tidal forces that translate to the heating of the body's interior.

It's that interaction that led Běhounková et al.'s research toward the conclusion that this resonance and the associate tidal forces can cause increased periods of volcanic activity — called magmatic pulses — on Europa.

Journal Reference:
Marie Běhounková, Gabriel Tobie, Gaël Choblet, et al. Tidally Induced Magmatic Pulses on the Oceanic Floor of Jupiter's Moon Europa, Geophysical Research Letters (DOI: 10.1029/2020GL090077)

Previously: Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Plate Tectonics on Europa and Subsurface Oceans in the Outer Solar System
NASA Finds Evidence of Water Plume on Europa
Europa Plume Sites Lack Expected Heat Signatures
Jupiter's Watery Moon, Europa, Is Covered in Table Salt
Jupiter's Ocean Moon Europa Probably Glows in the Dark

Original Submission

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  • (Score: 2) by Runaway1956 on Friday April 14 2017, @05:56PM

    by Runaway1956 (2926) Subscriber Badge on Friday April 14 2017, @05:56PM (#494116) Journal

    we're gonna wake 'em up!

  • (Score: 3, Interesting) by Azuma Hazuki on Friday April 14 2017, @07:40PM (2 children)

    by Azuma Hazuki (5086) on Friday April 14 2017, @07:40PM (#494160) Journal

    Didn't a scientist at Woods Hole recently just ask, regarding the hydrogen, "If there's all this free lunch around, how come no one's eating it?" That doesn't prove there's no life, but he raises a good point.

    I am "that girl" your mother warned you about...
    • (Score: 0) by Anonymous Coward on Friday April 14 2017, @07:45PM

      by Anonymous Coward on Friday April 14 2017, @07:45PM (#494162)

      "although the detection of hydrogen gas does not prove that the internal ocean currently contains life forms, and phosphorus and sulfur have yet to be measured."

      - takyon

    • (Score: -1, Troll) by Anonymous Coward on Friday April 14 2017, @08:12PM

      by Anonymous Coward on Friday April 14 2017, @08:12PM (#494177)

      If there was, that plume would be 98% Mexican.