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Life’s Origins in the Cosmos

To make life happen you need organic molecules that contain nitrogen. Now new work at NASA’s Ames Research Center, to be reported in the October 10 issue of the Astrophysical Journal, reveals that organic molecules found throughout the galaxy do, in fact, contain nitrogen. “Our work shows a class of compounds that is critical to biochemistry is prevalent throughout the universe,” said Douglas Hudgins, an astronomer at NASA Ames and principal author of the study. The studies combined laboratory experiments and computer simulations.

We already knew, thanks to the Spitzer Space Telescope, that complex organic molecules called polycyclic aromatic hydrocarbons (PAHs) are all but ubiquitous. Learning that PAHs contain nitrogen implies that the building blocks of life are seeded everywhere in the universe. From a NASA Ames news release, quoting astrochemist and team member Louis Allamandola:

“Chlorophyll, the substance that enables photosynthesis in plants, is a good example of this class of compounds, called polycyclic aromatic nitrogen heterocycles, or PANHs. Ironically, PANHs are formed in abundance around dying stars. So even in death, the seeds of life are sewn,” Allamandola said.

You can learn much more about this research and how it proceeded from the NASA Ames site. From the analysis found there:

This is the first direct evidence for the presence of complex, prebiotically important, biogenic compounds in space and brings us a step closer to assessing if life’s origin on Earth may have had a helping hand from infalling stardust. The bulk of the astronomical evidence points to the formation of these nitrogen containing PAHs in the winds of dying stars which inject them into interstellar space. Eventually they become incorporated into the clouds of material that give birth to stars and planets. Freshly formed planets continue to collect infalling material (dust, asteroids, meteorites, and comets) from the star formation process and life on Earth is thought to have emerged from this primordial chemical soup.

A preprint of the paper is also available (PDF warning).

M81 Spiral GalaxyImage (click to enlarge): NASA Spitzer Space Telescope image of the spiral galaxy M81, located some 12 million light years from Earth. The infrared radiation emitted by polycyclic nitrogen-containing aromatic hydrocarbon (PANH) molecules is shown in red. This emission is excited by star (and planet) formation along the edges of the spiral arms. Credit: NASA Ames.

Centauri Dreams‘ take: according to the Ames researchers, more than a hundred tons of extraterrestrial materials fall to Earth every year, much of it in the form of organic compounds. Imagine how much greater the amount of such infall must have been in the era when the planets were still young and the Sun’s debris disk more congested. The primordial Earth must have been inundated with compounds now understood to be complex and significant in the formation of life. Clearly, the study of life on Earth and presumably elsewhere in the cosmos now links directly to the study of interstellar chemistry.

Does this conclusion have implications for the Fermi paradox? A recent paper in the Journal of the British Interplanetary Society discusses the ‘where are they’ question in the context of discoveries like the above. We’ll look at Deardorff, Haisch et al., “Inflation-Theory Implications for Extraterrestrial Visitation” in an upcoming entry.

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  • ljk April 3, 2007, 15:31

    Primordial Soup’s On: Scientists Repeat Evolution’s Most Famous Experiment

    http://sciam.com/article.cfm?chanID=sa004&articleID=9952573C-E7F2-99DF-32F2928046329479

    Their results could change the way we imagine life arose on early Earth

    By Douglas Fox

    A Frankensteinesque contraption of glass bulbs and crackling electrodes has produced yet another revelation about the origin of life.

    The results suggest that Earth’s early atmosphere could have produced chemicals necessary for life—contradicting the view that life’s building blocks had to come from comets and meteors. “Maybe we’re over-optimistic, but I think this is a paradigm shift,” says chemist Jeffrey Bada, whose team performed the experiment at the Scripps Institution of Oceanography in La Jolla, Calif.

  • ljk May 23, 2007, 23:53

    The news release below can be found at

    http://ucsdnews.ucsd.edu/newsrel/science/05-07OriginofLifeKM-.asp

    Father of ‘Origin of Life’ Chemistry at UC San Diego Dies

    By Daniel Kane

    Stanley L. Miller, an emeritus professor of chemistry and biochemistry at
    the University of California, San Diego whose famous laboratory experiments
    in 1952 demonstrated how the simple organic compounds considered necessary for
    the origin of life could have been synthesized on the primitive Earth, died
    yesterday. He was 77.

    Miller, who had suffered a series of strokes since 1999 and was living in a
    nursing home in National City, south of San Diego, died at Paradise Hospital
    in National City.

    One of the founding chemists of UCSD, Miller was a graduate student at the
    University of Chicago in the 1950s, working under the late Harold Urey, a
    Nobel laureate who later moved to La Jolla and founded UCSD’s chemistry
    department. On May 15, 1953, Miller published a paper in the journal Science
    detailing a novel experiment that produced the building blocks of life from
    nothing more than hydrogen, water, methane and ammonia.

    No one then knew how the organic compounds found in life could have originated
    on the barren, primitive Earth, which Urey surmised had coalesced from a
    cloud of dust and was initially surrounded by an atmosphere of hydrogen, water,
    ammonia and methane – some of the major components of the universe.

    So Miller put water and ammonia into a globe-shaped flask with hydrogen and
    methane gas, boiled the solution and zapped the contents with an electrical
    discharge to simulate lightning and coronal discharges in the atmosphere.
    Within a week, he had produced a “molecular soup” containing amino acids,
    the building blocks of proteins and of life itself.

    “The public’s imagination was captivated by the outcome of the experiment,”
    said Jeffrey L. Bada, a professor of marine chemistry at UCSD’s Scripps
    Institution of Oceanography who was one of Miller’s graduate students at
    UCSD and a leading expert on the chemical origin of life. “By the time the
    results were corroborated by an independent group three years later, the
    metaphor of the ‘prebiotic soup’ had found its way into comic strips, cartoons,
    movies and novels.”

    Miller, the first assistant professor of chemistry recruited to work at UCSD,
    continued his research into the chemical origins of life for over four decades
    in La Jolla and helped to establish the university’s strong tradition of
    interdisciplinary research.

    “Like Roger Revelle, who built UCSD from the ‘top down’ with the best and the
    brightest, Miller and Urey were bold thinkers with a broad knowledge of
    science and gifted scientific intuitions who opened new disciplines in their
    quest to understand our origins,” said Mark Thiemens, dean of the Division of
    Physical Sciences at UCSD.

    “Stanley Miller was the father of origin of life chemistry,” said Bada. “And
    he was a leader in that field for many decades, remaining active even after
    his first stroke in November, 1999. It was the Miller experiment that almost
    overnight transformed the study of the origin of life into a respectable field
    of inquiry.”

    Stanley Miller was born in Oakland, Ca. on March 7, 1930. His father was an
    assistant district attorney in Oakland, appointed to his position by
    former California Governor and U.S. Chief Justice Earl Warren.

    He received his bachelor’s degree in chemistry from UC Berkeley in 1951 and
    his doctorate from the University of Chicago in 1954. He spent a year at
    Caltech on a fellowship, then five more years at Columbia University before
    joining the faculty of the newly formed San Diego campus of the University of
    California.

    Most of his research had been focused on the origin of life, especially the
    prebiotic synthesis of small molecules. In addition, he was a pioneer in the
    investigation of the natural occurrence of clathrate hydrates, the mechanism
    of the action of general anesthetics and the thermodynamics of bioorganic
    compounds.

    Miller was a member of the prestigious National Academy of Sciences. He
    received the Oparin Medal from the International Society of the Study of the
    Origin of Life in 1983 and was president of the society from 1986 to 1989.
    He was also an Honorary Counselor of the Higher Council for Scientific
    Research of Spain in 1973.

    He is survived by his family consisting of his brother Donald, a retired
    physical chemist, and sister-in-law Miriam of Livermore, Ca; two nieces,
    Nancy Miller of Washington, DC and Lynne Miller Franco of Silver Spring, Md.,
    and her two children, Lucio and Elena Franco of Silver Spring, Md.; and
    his devoted care-giver and companion Maria Morris.

    No funeral service is planned, although a memorial service will be scheduled
    at a future date. Miller’s family requests that donations be sent to the
    Miller Archival Fund at UCSD Libraries.

  • ljk July 23, 2007, 10:50

    Interstellar Chemistry Gets More Complex

    With New Charged-Molecule Discovery

    Astronomers using data from the National Science Foundation’s

    Robert C. Byrd Green Bank Telescope (GBT) have found the largest

    negatively-charged molecule yet seen in space. The discovery

    of the third negatively-charged molecule, called an anion,

    in less than a year and the size of the latest anion will

    force a drastic revision of theoretical models of interstellar

    chemistry, the astronomers say.

    “This discovery continues to add to the diversity and complexity

    that is already seen in the chemistry of interstellar space,”

    said Anthony J. Remijan of the National Radio Astronomy Observatory

    (NRAO). “It also adds to the number of paths available for making

    the complex organic molecules and other large molecular species

    that may be precursors to life in the giant clouds from which

    stars and planets are formed,” he added.

    Two teams of scientists found negatively-charged octatetraynyl,

    a chain of eight carbon atoms and one hydrogen atom, in the

    envelope of gas around an old, evolved star and in a cold, dark

    cloud of molecular gas. In both cases, the molecule had an extra

    electron, giving it a negative charge. About 130 neutral and about

    a dozen positively-charged molecules have been discovered in space,

    but the first negatively-charged molecule was not discovered until

    late last year. The largest previously-discovered negative ion

    found in space has six carbon atoms and one hydrogen atom.

    “Until recently, many theoretical models of how chemical reactions

    evolve in interstellar space have largely neglected the presence of

    anions. This can no longer be the case, and this means that there are

    many more ways to build large organic molecules in cosmic environments

    than have been explored,” said Jan M. Hollis of NASA’s Goddard Space

    Flight Center (GSFC).

    Ultraviolet light from stars can knock an electron off a molecule,

    creating a positively-charged ion. Astronomers had thought that

    molecules would not be able to retain an extra electron, and thus

    a negative charge, in interstellar space for a significant time.

    “That obviously is not the case,” said Mike McCarthy of the Harvard-

    Smithsonian Center for Astrophysics (CfA). “Anions are surprisingly

    abundant in these regions.”

    Remijan and his colleagues found the octatetraynyl anions in the

    envelope of the evolved giant star IRC +10 216, about 550 light-years

    from Earth in the constellation Leo. They found radio waves emitted

    at specific frequencies characteristic of the charged molecule by

    searching archival data from the GBT, the largest fully-steerable

    radio telescope in the world.

    Another team from the Harvard-Smithsonian Center for Astrophysics

    (CfA) found the same characteristic emission when they observed a cold

    cloud of molecular gas called TMC-1 in the constellation Taurus.

    These observations also were done with the GBT. In both cases,

    preceding laboratory experiments by the CfA team showed which radio

    frequencies actually are emitted by the molecule, and thus told the

    astronomers what to look for.

    “It is essential that likely interstellar molecule candidates are first

    studied in laboratory experiments so that the radio frequencies they can emit

    are known in advance of an astronomical observation,” said Frank Lovas

    of the National Institute of Standards and Technology (NIST).

    Both teams announced their results in the July 20 edition of the

    Astrophysical Journal Letters.

    “With three negatively-charged molecules now found in a short period

    of time, and in very different environments, it appears that many

    more probably exist. We believe that we can discover more new species

    using very sensitive and advanced radio telescopes such as the GBT,

    once they have been characterized in the laboratory,” said Sandra

    Bruenken of the CfA.

    “Further detailed studies of anions, including astronomical observations,

    laboratory studies, and theoretical calculations, will allow us to

    use them to reveal new information about the physical and chemical

    processes going on in interstellar space,” said Martin Cordiner,

    of Queen’s University in Belfast, Northern Ireland.

    “The GBT continues to take a leading role in discovering, identifying

    and mapping the distribution of the largest molecules ever found in

    astronomical environments and will continue to do so for the next

    several decades,” said Phil Jewell of NRAO.

    In addition to Hollis, Lovas, Cordiner and Jewell, Remijan worked with

    Tom Millar of Queen’s University in Belfast, Northern Ireland, and

    Andrew Markwick-Kemper of the University of Manchester in the UK.

    Bruenken worked with McCarthy, Harshal Gupta, Carl Gottlieb,

    and Patrick Thaddeus, all of the Harvard-Smithsonian Center for

    Astrophysics.

    The National Radio Astronomy Observatory is a facility of the

    National Science Foundation, operated under cooperative agreement

    by Associated Universities, Inc.

    Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center

    for Astrophysics is a joint collaboration between the Smithsonian

    Astrophysical Observatory and the Harvard College Observatory. CfA

    scientists, organized into six research divisions, study the origin,

    evolution and ultimate fate of the universe.

    ###

    NOTE: This release, with graphics, is available on the NRAO

    Web site, at: http://www.nrao.edu/pr/2007/biganion/

  • ljk July 23, 2007, 15:55

    ARIZONA RADIO OBSERVATORY TEAM DISCOVERS

    SUPERGIANT STAR SPEWS MOLECULES NEEDED FOR LIFE

    Monday, July 23, 2007

    Contact information, Web sites listed at the end

    University of Arizona astronomers who are probing the oxygen-rich

    environment around a supergiant star with one of the world’s most sensitive

    radio telescopes have discovered a score of molecules that include compounds

    needed for life.

    “I don’t think anyone would have predicted that VY Canis Majoris is a

    molecular factory. It was really unexpected,” said Arizona Radio Observatory

    (ARO) Director Lucy Ziurys, UA professor of astronomy and of chemistry.

    “Everyone thought that the interesting chemistry in gas clouds around old

    stars was happening in envelopes around nearer, carbon-rich stars,” Ziurys

    said. “But when we started looking closely for the first time at an

    oxygen-rich object, we began finding all these interesting things that

    weren’t supposed to be there.”

    VY Canis Majoris, one of the most luminous infrared objects in the sky, is

    an old star about 5,000 light years away. It’s a half million times more

    luminous than the sun, but glows mostly in the infrared because it’s a cool

    star. It truly is “supergiant” — 25 times as massive as the sun and so huge

    that it would fill the orbit of Jupiter. But the star is losing mass so fast

    that in a million years — an astronomical eyeblink — it will be gone. The

    star already has blown away a large part of its atmosphere, creating its

    surrounding envelope that contains about twice as much oxygen as carbon.

    Ziurys and her colleagues are not yet halfway through their survey of VY

    Canis Majoris, but they’ve already published in the journal, Nature (June 28

    issue), about their observations of a score of chemical compounds. These

    include some molecules that astronomers have never detected around stars and

    are needed for life.

    Among the molecules Ziurys and her team reported in Nature are table salt

    (NaCl); a compound called phosphorus nitride (PN), which contains two of the

    five most necessary ingredients for life; molecules of HNC, which is a

    variant form of the organic molecule, hydrogen cyanide; and an ion molecule

    form of carbon monoxide that comes with a proton attached (HCO+).

    Astronomers have found very little phosphorus or ion molecule chemistry in

    outflows from cool stars until now.

    “We think these molecules eventually flow from the star into the

    interstellar medium, which is the diffuse gas between stars. The diffuse gas

    eventually collapses into denser molecular clouds, and from these solar

    systems eventually form,” Ziurys said.

    Comets and meteorites dump about 40,000 tons of interstellar dust on Earth

    each year. We wouldn’t be carbon-based life forms otherwise, Ziurys noted,

    because early Earth lost all of its original carbon in the form of a methane

    atmosphere.

    “The origin of organic material on Earth — the chemical compounds that

    make up you and me — probably came from interstellar space. So one can say

    that life’s origins really begin in chemistry around objects like VY Canis

    Majoris.”

    Astronomers previously studied VY Canis Majoris with optical and infrared

    telescopes. “But that’s kind of like diving in with a butcher knife to look

    at what’s there, when what you need is an oyster fork,” Ziurys said.

    The Arizona Radio Observatory’s 10-meter Submillimeter Telescope (SMT) on

    Mount Graham, Ariz., excels as a sensitive stellar “oyster fork.” Chemical

    molecules each possess their own unique radio frequencies. The astronomers

    identify the unique radio signatures of chemical compounds in laboratory

    work, enabling them to identify the molecules in space.

    The ARO team recently began testing a new receiver in collaboration with

    the National Radio Astronomy Observatory. The receiver was developed as a

    prototype for the Atacama Large Millimeter Array, a telescope under

    construction in Chile. The state-of-the-art receiver has given the SMT 10

    times more sensitivity at millimeter wavelengths than any other radio

    telescope. The SMT can now detect emission weaker than a typical light bulb

    from distant space at very precise frequencies.

    The UA team has discovered that the molecules aren’t just flowing out as a

    gas sphere around VY Canis Majoris, but also are blasting out as jets

    through the spherical envelope.

    “The signals we receive show not only which molecules are seen, but how the

    molecules are moving toward and away from us,” said Stefanie Milam, a recent

    doctoral graduate on the ARO team.

    The molecules flowing out from VY Canis Majoris trace complex winds in

    three outflows: the general, spherical outflow from the star, a jet of

    material blasting out towards Earth, and another jet shooting out a 45

    degree angle away from Earth.

    Astronomers have seen bipolar outflows from stars before, but not two,

    unconnected, asymmetric and apparently random outflows, Ziurys said.

    Ziurys said she believes the two random jets are evidence for what

    astronomers earlier proposed are “supergranules” that form in very massive

    stars, and has been seen in Betelgeuse. Supergranules are huge cells of gas

    that form inside the star, then float to the surface and are ejected out of

    the star, where they cool in space and form molecules, creating jet outflows

    with certain molecular compositions.

    Back in the 1960s, no one believed molecules could survive the harsh

    environment of space. Ultraviolet radiation supposedly reduced matter to

    atoms and atomic ions. Now scientists conclude that at least half of the gas

    in space between the stars within the 33-light-year inner galaxy is

    molecular, Ziurys said. “Our results are more evidence that we live in a

    really molecular universe, as opposed to an atomic one,” Ziurys said.

    The Arizona Radio Observatory (ARO) owns and operates two radio telescopes

    in southern Arizona: The former NRAO 12 Meter (KP12m) Telescope located 50

    miles southwest of Tucson on Kitt Peak and the Submillimeter Telescope (SMT)

    located on Mount Graham near Safford, Ariz. The telescopes are operated

    around-the-clock for about nine to 10 months per year for a combined 10,000

    hours per observing season. About 1,500 hours are dedicated to sub-mm

    wavelengths at the SMT. The ARO offices are centrally located in the Steward

    Observatory building on the UA campus in Tucson.

    ———————————————————-

    Contact Information

    Lucy Ziurys1-520-621-6525 lziurys@as.arizona.edu

    Stefanie Milam 1-520-977-5149 smilam@as.arizona.edu

    Aldo Apponi 1-520-621-2553 aapponi@as.arizona.edu

    Nick Woolf 1-520)-621-3234 nwoolf@as.arizona.edu

    Related Web sites

    UA Astrochemistry Group –

    http://www.chem.arizona.edu/faculty/ziur/ziur-group.html

    Arizona Radio Observatory – http://aro.as.arizona.edu/

    Life and Planets Astrobiology Center – http://www.laplace.arizona.edu/