alien life

Saturn moon Titan has chemical that could form bio-like ‘membranes’ says NASA

August 06, 2017

NASA researchers have found large quantities (2.8 parts per billion) of acrylonitrile* (vinyl cyanide, C2H3CN) in Titan’s atmosphere that could self-assemble as a sheet of material similar to a cell membrane.

Acrylonitrile (credit: NASA Goddard)

Consider these findings, presented July 28, 2017 in the open-access journal Science Advances, based on data from the ALMA telescope in Chile (and confirming earlier observations by NASA’s Cassini spacecraft):

Azotozome illustration (credit: James Stevenson/Cornell)

1. Researchers have proposed that acrylonitrile molecules could come together as a sheet of material similar to a cell membrane. The sheet could form a hollow, microscopic sphere that they dubbed an “azotosome.”

A bilayer, made of two layers of lipid molecules (credit: Mariana Ruiz Villarreal/CC)

2. The azotosome sphere could serve as a tiny storage and transport container, much like the spheres that biological lipid bilayers can form. The thin, flexible lipid bilayer is the main component of the cell membrane, which separates the inside of a cell from the outside world.

“The ability to form a stable membrane to separate the internal environment from the external one is important because it provides a means to contain chemicals long enough to allow them to interact,” said Michael Mumma, director of the Goddard Center for Astrobiology, which is funded by the NASA Astrobiology Institute.

Organic rain falling on a methane sea on Titan (artist’s impression) (credit: NASA Goddard)

3. Acrylonitrile condenses in the cold lower atmosphere and rains onto its solid icy surface, ending up in seas of methane liquids on its surface.

Illustration showing organic compounds in Titan’s seas and lakes (ESA)

4. A lake on Titan named Ligeia Mare that could have accumulated enough acrylonitrile to form about 10 million azotosomes in every milliliter (quarter-teaspoon) of liquid. Compare that to roughly a million bacteria per milliliter of coastal ocean water on Earth.

Chemistry in Titan’s atmosphere. Nearly as large as Mars, Titan has a hazy atmosphere made up mostly of nitrogen with a smattering of organic, carbon-based molecules, including methane (CH4) and ethane (C2H6). Planetary scientists theorize that this chemical make-up is similar to Earth’s primordial atmosphere. The conditions on Titan, however, are not conducive to the formation of life as we know it; it’s simply too cold (95 kelvins or -290 degrees Fahrenheit). (credit: ESA)

6. A related open-access study published July 26, 2017 in The Astrophysical Journal Letters notes that Cassini has also made the surprising detection of negatively charged molecules known as “carbon chain anions” in Titan’s upper atmosphere. These molecules are understood to be building blocks towards more complex molecules, and may have acted as the basis for the earliest forms of life on Earth.

“This is a known process in the interstellar medium, but now we’ve seen it in a completely different environment, meaning it could represent a universal process for producing complex organic molecules,” says Ravi Desai of University College London and lead author of the study.

* On Earth, acrylonitrile  is used in manufacturing of plastics.


NASA Goddard | A Titan Discovery

Abstract of ALMA detection and astrobiological potential of vinyl cyanide on Titan

Recent simulations have indicated that vinyl cyanide is the best candidate molecule for the formation of cell membranes/vesicle structures in Titan’s hydrocarbon-rich lakes and seas. Although the existence of vinyl cyanide (C2H3CN) on Titan was previously inferred using Cassini mass spectrometry, a definitive detection has been lacking until now. We report the first spectroscopic detection of vinyl cyanide in Titan’s atmosphere, obtained using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), collected from February to May 2014. We detect the three strongest rotational lines of C2H3CN in the frequency range of 230 to 232 GHz, each with >4σ confidence. Radiative transfer modeling suggests that most of the C2H3CN emission originates at altitudes of ≳200 km, in agreement with recent photochemical models. The vertical column densities implied by our best-fitting models lie in the range of 3.7 × 1013 to 1.4 × 1014 cm−2. The corresponding production rate of vinyl cyanide and its saturation mole fraction imply the availability of sufficient dissolved material to form ~107 cell membranes/cm3 in Titan’s sea Ligeia Mare.

References:

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We’ll find alien life in the next 20 years with our new, awesome telescopes says NASA

July 19, 2014

Milky_Way_IR_Spitzer-cropped-smaller-640x438

Fortunately, NASA is preparing to launch a couple of new telescopes that will make Hubble and Kepler look like tin toys by comparison. The Transiting Exoplanet Survey Satellite (TESS), which is essentially an upgraded version of Kepler, will launch in 2017. A year later in 2018, Hubble’s successor — the James Webb Space Telescope (JWST) — will launch as well. Between them, they should be able to find hundreds of thousands of planets, and then “sniff” out the atmospheric conditions using the JWST’s spectrometer to divine whether any alien life has lived or died there.

In a public meeting with NASA’s chief, the agency’s top scientists have said that they expect to find alien life within the next 20 years. Unfortunately, for those hoping that Europa or Mars might harbor life, NASA is fairly confident that the discovery of extraterrestrials will probably be outside our Solar System rather than within it. But still, suffice it to say, the discovery of life of any kind outside of Earth’s atmosphere would be massive news. Within 20 years, we could finally find out that we’re not alone in the universe — and, well, that would change everything.

This rather shocking belief — that we will find signs of alien life within 20 years — stems back to the massive success of the Kepler space telescope. Kepler was designed to seek out distant stars with orbiting planets — and that’s exactly what it found, in spades. In just 2014 alone, and while staring at just a tiny patch of night sky, Kepler confirmed the existence of more than 700 new planets. Thanks to Kepler, the astronomy community now thinks that every star is orbited by at least one planet, and probably a lot more than one. When you consider that there are around 300 billion stars in just the Milky Way, and billions of galaxies in the universe, and thus an almost inconceivable number of planets in the universe, it’s easy to see why many scientists believe alien life to be a near certainty.

While Kepler can spot planets that orbit distant stars, it has two limitations. One, it can only spot fairly large planets (much larger than Earth) — and two, it can’t actually tell us what the atmospheric conditions are like on the new planets. While the size of the planet isn’t all that significant (its orbital period and distance from its parent star is more important), being able to analyze the atmosphere is key to discovering whether it harbors life or not (and for discerning habitability, if we want to one day visit or colonize the planet).

Hubble vs. James Webb Space Telescope, primary mirror size

Fortunately, NASA is preparing to launch a couple of new telescopes that will make Hubble and Kepler look like tin toys by comparison. The Transiting Exoplanet Survey Satellite (TESS), which is essentially an upgraded version of Kepler, will launch in 2017. A year later in 2018, Hubble’s successor — the James Webb Space Telescope (JWST) — will launch as well. Between them, they should be able to find hundreds of thousands of planets, and then “sniff” out the atmospheric conditions using the JWST’s spectrometer to divine whether any alien life has lived or died there.

At the NASA meeting, the agency’s chief Charles Bolden said, “It’s highly improbable in the limitless vastness of the universe that we humans stand alone.” NASA astronomer Kevin Hand went as far as to say, “I think in the next 20 years we will find out we are not alone in the universe.” John Grunsfeld, a veteran astronaut that’s now a NASA science chief, said, “This technology we are using to explore exoplanets is real. The James Webb Space Telescope and the next advances are happening now. These are not dreams – this is what we do at NASA.”

Suffice it to say, if JWST can identify signs of life in the atmosphere of a remote planet — methane or some other biological marker perhaps — then everything would change. We would no longer be alone in the universe. We could no longer putter around indefinitely, causing untold damage to Earth’s ecology. If it turns out that much of the universe is already occupied with other life forms, we’d have to actually get a move on and colonize some darn planets.

http://www.extremetech.com/extreme/186321-well-find-alien-life-in-the-next-20-years-with-our-new-awesome-telescopes-says-nasa