. 24/7 Space News .
SATURN DAILY
Cutting through the mystery of Titan's atmospheric haze
by Staff Writers
Berkeley CA (SPX) Oct 09, 2018

The atmospheric haze of Titan, Saturn's largest moon is captured in this natural-color image. A new study, which involved experiments at Berkeley Lab's Advanced Light Source, has provided new clues about the chemical steps that may have produced this haze.

Saturn's largest moon, Titan, is unique among all moons in our solar system for its dense and nitrogen-rich atmosphere that also contains hydrocarbons and other compounds, and the story behind the formation of this rich chemical mix has been the source of some scientific debate.

Now, a research collaboration involving scientists in the Chemical Sciences Division at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has zeroed in on a low-temperature chemical mechanism that may have driven the formation of multiple-ringed molecules - the precursors to more complex chemistry now found in the moon's brown-orange haze layer.

The study, co-led by Ralf Kaiser at the University of Hawaii at Manoa and published in the Oct. 8 edition of the journal Nature Astronomy, runs counter to theories that high-temperature reaction mechanisms are required to produce the chemical makeup that satellite missions have observed in Titan's atmosphere.

The team also included other researchers at Berkeley Lab, the University of Hawaii at Manoa, Samara University in Russia, and Florida International University. The team used vacuum ultraviolet light experiments at Berkeley Lab's Advanced Light Source (ALS), together with computer simulations and modeling work to demonstrate the chemical reactions that contribute to Titan's modern-day atmospheric chemistry.

"We provide evidence here for a low-temperature reaction pathway that people have not thought about," said Musahid Ahmed, a scientist in Berkeley Lab's Chemical Sciences Division and co-leader of the study at the ALS. "This gives rise to a missing link in Titan's chemistry."

Titan may yield clues to the development of complex chemistry on other moons and planets, including Earth, he explained. "People use Titan to think about a 'pre-biotic' Earth - when nitrogen was more prevalent in the early Earth's atmosphere."

Benzene, a simple hydrocarbon with a six-carbon single-ring molecular structure, has been detected on Titan and is believed to be a building block for larger hydrocarbon molecules with two- and three-ring structures that, in turn, formed other hydrocarbons and aerosol particles that now make up Titan's atmosphere. These multiple-ring hydrocarbon molecules are known as polycyclic aromatic hydrocarbons (PAHs).

In the latest study, researchers mixed two gases - a short-lived two-ring PAH known as a naphthyl radical (C10H7) and a hydrocarbon called vinylacetylene (C4H4) - at the ALS, and produced three-ring PAHs in the process. Both of the chemicals used to drive the reaction are inferred to exist on Titan based on what is known about the chemical makeup of its atmosphere.

The ALS experiments jetted away the end products of the reactions from a small reaction chamber. Researchers used a detector known as a reflectron time-of-flight mass spectrometer to measure the mass of molecular fragments produced in the reaction of the two gases. Those measurements supplied details about the chemistry of the three-ring PAHs (phenanthrene and anthracene).

While the ALS experiments used a chemical reactor to simulate the chemical reaction and a beam of vacuum ultraviolet light to detect the products of the reaction, supporting calculations and simulations showed how the chemicals formed in the ALS experiments do not require high temperatures.

PAHs like the chemicals studied at the ALS have properties that make them particularly difficult to identify in deep space, Kaiser said. "In fact, not a single, individual PAH has been detected in the gas phase of the interstellar medium," which is the material that fills the space between stars.

He added, "Our study demonstrates that PAHs are more widely spread than anticipated, since they do not require the high temperatures that are present around carbon stars. This mechanism we explored is predicted to be versatile and is expected to lead to the formation of even more complex PAHs."

And because PAHs are considered as precursors to forming molecular clouds - the so-called "molecular factories" of more complex organic molecules that can include the precursors to life as we know it - "This could open up theories and new models of how carbon-containing material in deep space and in the rich atmospheres of planets and their moons in our solar system evolve and originate," he said.

Alexander M. Mebel, a chemistry professor at Florida International University and co-leader of the study, carried out calculations that showed how the reactants can naturally come together and form new compounds at very low temperatures.

"Our calculations revealed the reaction mechanism," Mebel said. "We showed that you don't need any energy to drive the reaction of naphthyl and vinylacetylene, so the reaction should be efficient even in the low-temperature and low-pressure atmospheric conditions on Titan."

A key to the study was in the detailed modeling of the reactor cell where the gases were mixed.

Mebel noted that modeling of the energies and simulations of the gas-flow dynamics in play within the reactor help to monitor reaction progress inside the reactor, and allowed researchers to tie theoretical results closely with experimental observations.

The modeling work, which helped to predict the chemicals produced in the reactions based on the initial gases and the temperature and pressure of the heated chamber where the gases were mixed and struck with the vacuum ultraviolet beam, was led by the research team at Samara University.

"This verification of the model, by comparing it with experiments, can also be helpful in predicting how the reaction would proceed in different conditions - from Titan's atmosphere to combustion flames on Earth."

An aim of the continuing research, Kaiser said, is to unravel the details of how carbon-containing compounds with similar structures to DNA and RNA can develop even in extreme environments.

Research paper


Related Links
Lawrence Berkeley National Laboratory
Explore The Ring World of Saturn and her moons
Jupiter and its Moons
The million outer planets of a star called Sol
News Flash at Mercury


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


SATURN DAILY
Hubble observes energetic light show at Saturn's north pole
Washington DC (SPX) Aug 31, 2018
Astronomers using the Hubble Space telescope have taken a series of images featuring the fluttering auroras at the north pole of Saturn. The observations were taken in ultraviolet light and the resulting images provide astronomers with the most comprehensive picture so far of Saturn's northern aurora. In 2017, over a period of seven months, the NASA/ESA Hubble Space Telescope took images of auroras above Saturn's north pole region using the Space Telescope Imaging Spectrograph. The observations we ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

SATURN DAILY
Space Station Crew Returns to Earth, Lands Safely in Kazakhstan

First UAE Astronaut to Fly to ISS for 11-Day Mission on April 5, 2019

NASA skeptical on sabotage theory after mystery ISS leak

Russia to help India in its first manned space mission

SATURN DAILY
First SpaceX mission with astronauts set for June 2019: NASA

SpaceX uses dumping to drive Russia out of space launch market claims Roscosmos

SLS chief engineer driven by 'challenge' of building rocket

Nucleus completes successful first launch

SATURN DAILY
Curiosity Rover to Temporarily Switch 'Brains'

Curiosity rover operating on backup computer during repairs to main processor

Opportunity Remains Silent For Over Three Months

Software finds the best way to stick a Mars landing

SATURN DAILY
China launches Centispace-1-s1 satellite

China tests propulsion system of space station's lab capsules

China unveils Chang'e-4 rover to explore Moon's far side

China's SatCom launch marketing not limited to business interest

SATURN DAILY
Britain and Australia enter into space agreement

See the future at ESA's IAC Start-up Space Zone

Ten years catching rocket signals

Thinkom develops enterprise user terminal for Telesat's LEO constellation

SATURN DAILY
Researchers discover highly active organic photocatalyst

NTU Singapore scientists develop smart technology for synchronized 3D printing of concrete

Brazil says Norsk Hydro lacked waste license for stalled plant

Reaction of a quantum fluid to photoexcitation of dissolved particles observed for the first time

SATURN DAILY
Liquid crystals and the origin of life

'Spacesuits' protect microbes destined to live in space

Astronomers find first evidence of possible moon outside our Solar System

New tool helps scientists better target the search for alien life

SATURN DAILY
While seeking Planet X, astronomers find a distant solar system object

New Horizons sets up for New Year's flyby of Ultima Thule

Extremely distant Solar System object found

New Horizons Team Rehearses For New Year's Flyby









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.