Saturn’s Moon Enceladus Shows More Signs It Could Support Alien Life

Saturn’s icy moon Enceladus is looking more and more like a habitable world.

The same sorts of chemical reactions that sustain life near deep-sea hydrothermal vents here on Earth could potentially be occurring within Enceladus’ subsurface ocean, a new study published today (April 13) in the journal Science suggests.

These reactions depend on the presence of molecular hydrogen (H2), which, the new study reports, is likely being produced continuously by reactions between hot water and rock deep down in Enceladus’ sea.

Related: Photos of Enceladus, Saturn’s Geyser-Blasting Moon

“The abundance of H2, along with previously observed carbonate species, suggests a state of chemical disequilibria in the Enceladus ocean that represents a chemical energy source capable of supporting life,” Jeffrey Seewald, of the Marine Chemistry and Geochemistry Department at the Woods Hole Oceanographic Institution in Massachusetts, wrote in an accompanying “Perspectives” piece in the same issue of Science. (Seewald was not involved in the new Enceladus study.)

A Geyser-Blasting Ocean World

The 313-mile-wide (504 kilometers) Enceladus is just Saturn’s sixth-largest moon, but the object has loomed large in the minds of astrobiologists since 2005.

In that year, NASA’s Saturn-orbiting Cassini spacecraft first spotted geysers of water ice erupting from “tiger stripe” fissures near Enceladus’ south pole. Scientists think these geysers are blasting material from a sizeable ocean buried beneath the satellite’s ice shell.

So, Enceladus has liquid water, one of the key ingredients required for life as we know it. (This ocean stays liquid because Saturn’s immense gravitational pull twists and stretches the moon, generating internal “tidal” heat.) And the new study suggests that the satellite possesses another key ingredient as well: an energy source.

 

A team of researchers led by Hunter Waite, of the Southwest Research Institute (SwRI) in San Antonio, analyzed observations made by Cassini during an October 2015 dive through Enceladus’ geyser plume.

This plunge was special in several ways. For one thing, it was Cassini’s deepest-ever dive through the plume; the probe got within a mere 30 miles (49 km) of Enceladus’ surface. In addition, Cassini’s Ion and Neutral Mass Spectrometer (INMS) instrument alternated between “open-source” and “closed-source” modes during the encounter, rather than sticking to closed source (the usual routine).

INMS is just 0.25 percent as sensitive in open-source mode as it is in closed-source mode, Waite and his colleagues wrote in the new Science paper. But open source has a key advantage: It minimizes artifacts that have complicated previous attempts to measure H2 levels in the plume.

With this analytical hurdle cleared, Waite and his team were able to calculate that H2 makes up between 0.4 percent and 1.4 percent of the volume of Enceladus’ geyser plume. Further calculations revealed that carbon dioxide (CO2) makes up an additional 0.3 percent to 0.8 percent of the plume’s volume.

Related: Inside Enceladus, Icy Moon of Saturn (Infographic)

The molecular hydrogen is most likely being produced continuously by reactions between hot water and rock in and around Enceladus’ core, Waite and his colleagues concluded. They considered other possible explanations and found them wanting. For example, neither Enceladus’ ocean nor its ice shell are viable long-term reservoirs for volatile H2, the authors wrote, and processes that disassociate H2 from water ice in the shell don’t seem capable of generating the volume measured in the plume.

The hydrothermal explanation is also consistent with a 2016 study by another research group, which concluded that tiny silica grains detected by Cassini could have been produced only in hot water at significant depths.

“The story seems to be fitting together,” Chris Glein of SwRI, a co-author of the new Science paper, told Space.com.

Deep-Sea Chemical Reactions

Earth’s deep-sea hydrothermal vents support rich communities of life, ecosystems powered by chemical energy rather than sunlight.

“Some of the most primitive metabolic pathways utilized by microbes in these environments involve the reduction of carbon dioxide (CO2) with H2 to form methane (CH4) by a process known as methanogenesis,” Seewald wrote.

The inferred presence of H2 and CO2 in Enceladus’ ocean therefore suggests that similar reactions could well be occurring deep beneath the moon’s icy shell. Indeed, the observed H2 levels indicate that a lot of chemical energy is potentially available in the ocean, Glein said.

“It’s quite a bit larger than the minimum energy required to support methanogenesis,” he said.

Glein stressed, however, that nobody knows whether such reactions are actually occurring on Enceladus.

“This is not a detection of life,” Glein said. “It increases the habitability, but I would never suggest that this makes Enceladus more or less likely to have life itself. I think the only way to answer that question is, we need data.”

Seewald also counseled caution on astrobiological interpretations. He noted, for example, that molecular hydrogen is rare in Earth’s seawater, because hungry microbes quickly gobble it up.

“Is the presence of H2 in the Enceladus ocean an indicator for the absence of life, or is it a reflection of the very different geochemical environment and associated ecosystems on Enceladus?” Seewald wrote. “We still have a long way to go in our understanding of processes regulating the exchange of mass and heat across geological interfaces that define the internal structure of Enceladus and other ice-covered planetary bodies.”

Originally published on Space.com.

What the view from earth would be like if earth had rings like Saturn

Solar siblings? Astronomers discover sun’s long-lost brother

The star HD 162826 is probably a “solar sibling,” that is, a star born in the same star cluster as the sun. It was identified by University of Texas at Austin astronomer Ivan Ramirez, in the process of honing a technique to find more solar siblings in the future, and eventually to determine how and where in the Milky Way galaxy the sun formed. (IVAN RAMIREZ/TIM JONES/MCDONALD OBSERVATORY)

It turns out that the sun has a long-lost brother — and now astronomers are racing to map a solar family tree.

A new study from researchers at the University of Texas provides clues as to how our sun was formed, whether there are other “solar siblings” in our universe and, perhaps, a better understanding of how life in the universe was formed billions of years ago.

The finding, which will be published next month in The Astrophysical Journal, identifies a star that was almost certainly born from the same cloud of gas and dust as the sun. Located 110 light years away in the constellation Hercules, the star, called HD 162826, is 15 percent more massive than our sun, and can be seen with low-power binoculars.

“We want to know where we were born,” University of Texas at Austin astronomer Ivan Ramirez said in a news release from McDonald Observatory. “If we can figure out in what part of the galaxy the sun formed, we can constrain conditions on the early solar system. That could help us understand why we are here.”

Ramirez and his eight-person team discovered HD 162826’s relation to the sun by following up on 30 possible candidates found by several groups around the world looking for solar siblings. Ramirez’s team studied 23 stars in-depth at McDonald Observatory and several stars, visible only from the southern hemisphere, using the Clay Magellan Telescope at Las Campanas Observatory in Chile. Both observations required the use of high-resolution spectorscopy to understand the stars’ chemical makeup.

There’s even a small chance these solar siblings could host life-sustaining planets. When these stars were born, collisions could have knocked chunks off planets, and these fragments could have traveled between solar systems — perhaps bringing primitive life to Earth. Conversely, fragments from Earth could have sent life to planets orbiting other stars.

“It could be argued that solar siblings are the key candidates in the search for extraterrestrial life,” Ramirez said.

Next, Ramirez’s team wants to create a road map for how to identify solar siblings, operating on the theory that the sun was born in a cluster with up to 100,000 stars. That cluster, however, formed more than 4.5 billion years ago, and has long since broken up, spreading the stars out to different parts of the Milky Way galaxy. Finding more solar siblings will provide the best clues toward discovering our sun’s origin, and Ramirez’s discovery is an important step in streamlining the identification process when it comes to tracking down stars with the same galactic DNA, he told FoxNews.com on Friday.

“Already, we’re getting a lot of data from a number of surveys,” Ramirez told FoxNews.com on Friday. “In five to 10 years from now, we’re going to be able to analyze 10,000 times more stars than what we’re able to do right now.”

Source

‘Nile river’ discovered on Saturn moon Titan — first river on another planet

Dec. 12, 2012: NASA’s Cassini spacecraft has discovered a vast river system on Saturn’s moon Titan. It is the first time images from space have revealed a river system so vast and in such high resolution anywhere other than Earth (NASA/JPL-Caltech/ASI)

The Cassini Solstice mission has discovered what appears to be a miniature version of the Nile River on Saturn’s largest moon, Titan. In comparison, the Nile is 4,132 miles long. The 250-mile long feature — from ‘headwaters’ to a large sea — is the longest extraterrestrial river ever to be discovered and imaged to such high resolution.

Using Cassini’s radar imaging instruments, mission scientists were able to deduce that the feature is indeed a river as the dark, smooth surface within the meanders and channel suggest the presence of a liquid.

ANALYSIS: The ‘Tropical’ Lakes of Saturn’s Moon Titan

 

‘The relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers.’

– Jani Radebaugh, Cassini radar team associate at Brigham Young University

 

Titan is known to have vast lakes — the only other body in the solar system, apart from Earth, to possess a cycle of liquids on its surface. However, the thick Titan atmosphere is a frigid one, meaning liquid water couldn’t possibly flow. The liquids on Titan are therefore composed of hydrocarbons such as methane and ethane.

Interestingly, using this observation of a vast river system on Titan reveals not only that rivers flow, it could also trace the path of fault lines on the Saturnian moon, suggestive of fractures in Titan’s bedrock.

“Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea,” said Jani Radebaugh, Cassini radar team associate at Brigham Young University.

“Such faults — fractures in Titan’s bedrock — may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves.”

ANALYSIS: Need a Vacation? Visit Titan’s Exotic Ontario Lacus

The discovery of vast river systems on Titan was perhaps inevitable. Cassini has previously confirmed the presence of large masses of liquid including Ontario Lacus, a lake in the southern hemisphere composed of liquid ethane. Rainfall has also been detected in the atmosphere, hinting not of a hydrological cycle (which gives us water rain, rivers and oceans on Earth), but of a methane cycle.

It is hard not to imagine what such a river system would look like when standing next to it. But looking at this radar observation, many familiar river features such as meanders and channels can be seen.

Titan is a complex and fascinating little world laced with complex prebiotic chemistry. Apart from the Huygens probe that landed on the surface in 2005, there have been no other surface missions and plans for future missions look iffy at best.

ANALYSIS: Titan’s Hazy History and the Potential for Life

Titan might be shrouded in a cold, high pressure atmosphere that makes it difficult for our robots to explore, but it’s hard to ignore the fact that the ingredients for the basic chemistry for life is there in abundance — could there be a form of life there, perhaps taking advantage of liquid methane and ethane rather than water? We may be waiting some time to find out.
Source

Enceladus has ‘spreading surface’

The tiger stripe fractures (bottom right) are places where the surface spreads

By Jonathan Amos
Science reporter, BBC News, San Francisco

A US space agency (Nasa) probe has witnessed a moon of Saturn do something very unusual and Earth-like.

Pictures of the icy satellite Enceladus suggest its surface splits and spreads apart – just like the ocean floor on our planet splits to create new crust.

The information was released at a meeting of the American Geophysical Union in San Francisco.

Evidence is mounting that liquid water lies beneath the surface

The data from the Cassini spacecraft is said to strengthen the idea that Enceladus harbours a sub-surface sea.

“Bit by bit, we’re accumulating the evidence that there is liquid water on Enceladus,” said Carolyn Porco, team leader of the Cassini imaging group and one of the senior scientists on the mission.

The observation on Earth that the sea floor is splitting at mid-ocean ridges and moving apart was one of the great scientific discoveries of the 20th Century; and became a key feature in the theory of plate tectonics – the idea that massive slabs of the Earth’s surface move around and are recycled.

Cassini sees something very similar on Enceladus.

The surface of this snow-white moon is riven with cracks – dubbed tiger stripes – at its south pole.

Dr Paul Helfenstein from Cornell University used digital maps of this region to reconstruct a history of the stripes, pushing the fractures around on a computer screen until they fitted together like pieces in a puzzle.

He found that sections of the cracks had clearly moved from their original locations.

Dr Helfenstein told BBC News that the resemblance to the Earth process was remarkable.

“What’s different about them is that spreading ridges on the Earth typically spread symmetrically about a rift,” he said.

“On Enceladus, what we see is a type of spreading but it is strongly asymmetric – it’s like a conveyor belt, in which, if it’s true it’s coming up from a convection well, it seems to be only pushing in one direction. It does happen on Earth, but only in very peculiar situations.”

On Earth, sea-floor spreading is fuelled by molten rock upwelling from deep inside the Earth.

On Enceladus, the scientists speculate the liquid may be water.

If that is the case, it makes this moon one of the most exciting targets for future exploration.

Enceladus is already known to have some of the fundamental chemistry required to make and sustain life. Liquid water currently is the major missing ingredient.

Dr Porco commented: “We first discovered this region in early 2005 and now it’s nearly four years later, so it’s still kind of brand new; but already there are some of us who really want to go back with a spacecraft that focuses on the south pole of Enceladus and investigates whether or not it is a site of either pre-biotic or biotic processes.”

Source: http://news.bbc.co.uk/2/hi/science/nature/7784902.stm

Astronomers find hints of water on Saturn moon

WASHINGTON (AP) — Astronomers looking at the spectacular supersonic plumes of gas and dust shooting off one of Saturn’s moons say there are strong hints of liquid water, a key building block of life.

This 2007 photo by NASA's Cassini probe shows plumes of gas and dust shooting off Enceladus. (NASA)

One of Saturn's moons, Enceladus is the white orb in the middle of this image. (NASA)

Their research, appearing in Thursday’s issue of the journal Nature, adds to the growing push to explore further the moon Enceladus, as one of the solar system’s most compelling places for potential life.

Using images from NASA’s Cassini probe, astronomers had already figured that the mysterious plumes shooting from Enceladus’ icy terrain contain water vapor. New calculations suggesting the gas and dust spew at speeds faster-than-sound make the case for liquid, said study lead author Candice Hansen of NASA’s Jet Propulsion Lab in California. Her team calculated the plumes travel more than 1,360 mph.

More on the story, after the jump: http://www.cnn.com/2008/TECH/space/11/26/saturn.moon.water.ap/index.html

Dazzling Mysterious Aurora Spotted on Saturn

Bizzare Hexagon Pattern on Saturn

An inexplicable new broad region of auroral light has been photographed at Saturn’s polar cap. “We’ve never seen an aurora like this elsewhere,” said Tom Stallard, an RCUK Academic Fellow working with Cassini data at the University of Leicester. “It’s not just a ring of aurorae like those we’ve seen at Jupiter or Earth.

Friday, November 14, 2008

Story Continues Here: http://www.foxnews.com/story/0,2933,451372,00.html

Here is an awesome view of the Saturn Hexagons: http://apod.nasa.gov/apod/ap070403.html

Ever since the arrival of the Saturn probe Cassini, Saturn’s veil of mystery has begun to lift itself. Yet, at the same time, new mysteries have revealed themselves, and many like this one, continue to evolve. One such mystery lies in Saturn’s polar caps region. This is part of an ongoing new discovery process with astronomers in regards to Saturn as it’s polar regions have begun to unlock some fo the wild processes that occur on our most brilliant gas giant, Saturn.

Here is an older story in the continuing saga of Saturn’s polar regions:

Mysterious Hexagons

Bizarre Hexagon Spotted on Saturn

posted: 27 March 2007
01:18 pm ET

One of the most bizarre weather patterns known has been photographed at Saturn, where astronomers have spotted a huge, six-sided feature circling the north pole.

Rather than the normally sinuous cloud structures seen on all planets that have atmospheres, this thing is a hexagon.

The honeycomb-like feature has been seen before. NASA’s Voyager 1 and 2 spacecraft imaged it more than two decades ago. Now, having spotted it with the Cassini spacecraft, scientists conclude it is a long-lasting oddity.

“This is a very strange feature, lying in a precise geometric fashion with six nearly equally straight sides,” said Kevin Baines, atmospheric expert and member of Cassini’s visual and infrared mapping spectrometer team at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We’ve never seen anything like this on any other planet. Indeed, Saturn’s thick atmosphere, where circularly-shaped waves and convective cells dominate, is perhaps the last place you’d expect to see such a six-sided geometric figure, yet there it is.”

Story Continues Here: http://www.space.com/scienceastronomy/070327_saturn_hex.html