Posts Tagged ‘Saturn’

By Irene Klotz

Ice plumes shooting into space from Saturn’s ocean-bearing moon Enceladus contain hydrogen from hydrothermal vents, an environment that some scientists believe led to the rise of life on Earth, research publish”If correct, this observation has fundamental implications for the possibility of life on Enceladus,” geochemist Jeffrey Seewald, of the Woods Hole Oceanographic Institution in Massachusetts, wrote in a related commentary in Science.

The discovery was made using NASA’s Cassini spacecraft, which in September will end a 13-year mission exploring Saturn and its entourage of 62 known moons.

The detection of molecular hydrogen occurred in October 2015 during Cassini’s last pass through Enceladus’ plumes, when it skimmed 30 miles (49 km) above the moon’s southern pole taking samples.

In 2005, Cassini discovered Enceladus’s geysers, which shoot hundreds of miles into space. Some of the material falls back onto the surface as a fresh coat of ice, while much of the rest gathers into a halo of ice dust that feeds one of Saturn’s rings.ed on Thursday showed.

The discovery makes Enceladus the only place beyond Earth where scientists have found direct evidence of a possible energy source for life, according to the findings in the journal Science.

Similar conditions, in which hot rocks meet ocean water, may have been the cradle for the appearance of microbial life on Earth more than 4 billion years ago.

“If correct, this observation has fundamental implications for the possibility of life on Enceladus,” geochemist Jeffrey Seewald, of the Woods Hole Oceanographic Institution in Massachusetts, wrote in a related commentary in Science.

The discovery was made using NASA’s Cassini spacecraft, which in September will end a 13-year mission exploring Saturn and its entourage of 62 known moons.

The detection of molecular hydrogen occurred in October 2015 during Cassini’s last pass through Enceladus’ plumes, when it skimmed 30 miles (49 km) above the moon’s southern pole taking samples.

In 2005, Cassini discovered Enceladus’s geysers, which shoot hundreds of miles into space. Some of the material falls back onto the surface as a fresh coat of ice, while much of the rest gathers into a halo of ice dust that feeds one of Saturn’s rings.

A decade later, scientists measuring the moon’s slightly wobbly orbit around Saturn determined it holds a vast ocean buried 19- to 25 miles (30- to 40 km) beneath its icy shell. The ocean is believed to be the geysers’ source.

Several moons orbiting Jupiter and Saturn are known to contain underground oceans, but Enceladus is the only one where scientists have found proof of an energy source for life.

“We’re moving toward Enceladus’s ocean being habitable, but we’re not making any claims at this point about it being inhabited,” lead author Hunter Waite, with the Southwest Research Institute in San Antonio, Texas, said in an interview.

“The next time we go back … you’re going to take something that not only picks up on the habitability story, but it starts looking for evidence for life.”

Enceladus has a diameter of 310 miles (500 km) and is one of Saturn’s innermost moons. The heat needed to keep its ocean from freezing is thought to come from tidal forces exerted by Saturn and a neighboring larger moon, Dione.

http://www.reuters.com/article/us-space-saturn-moon-idUSKBN17F2DR

saturn

t sounds like a wacky fantasy, but scientists believe that it rains diamonds in the clouds of Saturn and Jupiter.

Diamonds are made from highly compressed and heated carbon. Theoretically, if you took a charcoal bricket out of your grill and heated it and pressed it hard enough for long enough, you could make a diamond.

On Earth, diamonds form about 100 miles underground. Volcanic magma highways then bring them closer to the surface, providing us with shiny gemstones that we stick in rings and ear studs.

But in the dense atmospheres of planets like Jupiter and Saturn, whose massive size generates enormous amounts of gravity, crazy amounts of pressure and heat can squeeze carbon in mid-air — and make it rain diamonds.

Scientists have speculated for years that diamonds are abundant in the cores of the smaller, cooler gas giants, Neptune and Uranus. They believed that the larger gaseous planets, Jupiter and Saturn, didn’t have suitable atmospheres to forge diamonds.

But when researchers recently analyzed the pressures and temperatures for Jupiter’s and Saturn’s atmospheres, then modeled how carbon would behave, they determined that diamond rain is very likely.

Diamonds seem especially likely to form in huge, storm-ravaged regions of Saturn, and in enormous quantities — Kevin Baines, a researcher at University of Madison-Wisconsin and NASA JPL, told BBC News it may rain as much as 2.2 million pounds of diamonds there every year.

The diamonds start out as methane gas. Powerful lightning storms on the two huge gas giants then zap it into carbon soot.

“As the soot falls, the pressure on it increases,” Baines told the BBC. “And after about 1,000 miles it turns to graphite – the sheet-like form of carbon you find in pencils.”

And the graphite keeps falling. When it reaches the deep atmosphere of Saturn, for example — around 3,700 miles down — the immense pressure squeezes the carbon into diamonds, which float in seas of liquid methane and hydrogen.

Eventually the gems sink toward the interior of the planet (a depth of 18,600 miles), where nightmarish pressure and heat melts the diamonds into molten carbon.

“Once you get down to those extreme depths,” Baines told the BBC, “the pressure and temperature is so hellish, there’s no way the diamonds could remain solid.”

http://www.techinsider.io/diamond-rain-saturn-jupiter-2016-4


Taking a simultaneously imaginative and rigidly scientific view, Cornell chemical engineers and astronomers offer a template for life that could thrive in a harsh, cold world – specifically Titan, the giant moon of Saturn. A planetary body awash with seas not of water, but of liquid methane, Titan could harbour methane-based, oxygen-free cells that metabolise, reproduce and do everything life on Earth does.

Their theorised cell membrane, composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero, was published in Science Advances, 27th February. The work is led by chemical molecular dynamics expert Paulette Clancy, the Samuel W. and Diane M. Bodman Professor of Chemical and Biomolecular Engineering, with first author James Stevenson, a graduate student in chemical engineering. The paper’s co-author is Jonathan Lunine, the David C. Duncan Professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy.
Lunine is an expert on Saturn’s moons and an interdisciplinary scientist on the Cassini-Huygens mission that discovered methane-ethane seas on Titan. Intrigued by the possibilities of methane-based life on Titan, and armed with a grant from the Templeton Foundation to study non-aqueous life, Lunine sought assistance about a year ago from Cornell faculty with expertise in chemical modeling. Clancy, who had never met Lunine, offered to help.

“We’re not biologists, and we’re not astronomers, but we had the right tools,” Clancy said. “Perhaps it helped, because we didn’t come in with any preconceptions about what should be in a membrane and what shouldn’t. We just worked with the compounds that we knew were there and asked, ‘If this was your palette, what can you make out of that?’”

On Earth, life is based on the phospholipid bilayer membrane, the strong, permeable, water-based vesicle that houses the organic matter of every cell. A vesicle made from such a membrane is called a liposome. Thus, many astronomers seek extraterrestrial life in what’s called the circumstellar habitable zone, the narrow band around the Sun in which liquid water can exist. But what if cells weren’t based on water, but on methane, which has a much lower freezing point?

The engineers named their theorised cell membrane an “azotosome,” “azote” being the French word for nitrogen. “Liposome” comes from the Greek “lipos” and “soma” to mean “lipid body;” by analogy, “azotosome” means “nitrogen body.”

The azotosome is made from nitrogen, carbon and hydrogen molecules known to exist in the cryogenic seas of Titan, but shows the same stability and flexibility that Earth’s analogous liposome does. This came as a surprise to chemists like Clancy and Stevenson, who had never thought about the mechanics of cell stability before; they usually study semiconductors, not cells.

The engineers employed a molecular dynamics method that screened for candidate compounds from methane for self-assembly into membrane-like structures. The most promising compound they found is an acrylonitrile azotosome, which showed good stability, a strong barrier to decomposition, and a flexibility similar to that of phospholipid membranes on Earth. Acrylonitrile – a colourless, poisonous, liquid organic compound used in the manufacture of acrylic fibres, resins and thermoplastics – is present in Titan’s atmosphere.

Excited by the initial proof of concept, Clancy said the next step is to try and demonstrate how these cells would behave in the methane environment – what might be the analogue to reproduction and metabolism in oxygen-free, methane-based cells.

Lunine looks forward to the long-term prospect of testing these ideas on Titan itself, as he put it, by “someday sending a probe to float on the seas of this amazing moon and directly sampling the organics.”

Stevenson said he was in part inspired by science fiction writer Isaac Asimov, who wrote about the concept of non-water-based life in a 1962 essay, “Not as We Know It.”

Said Stevenson: “Ours is the first concrete blueprint of life not as we know it.”

http://astronomynow.com/2015/03/01/life-not-as-we-know-it-possible-on-saturns-moon-titan/

Thanks to Da Brayn for bringing this to the attention of the It’s Interesting community.