1. Earth's Oldest Mineral Grains Suggest an Early Start for Life

    Scientists are drawing a portrait of how Earth looked soon after it formed 4.56 billion years ago, based on clues within the oldest mineral grains ever found.

    Tiny zircons (zirconium silicate crystals) deposited in ancient stream deposits appear to indicate that Earth developed continents and water — perhaps even oceans and environments in which microbial life could emerge — 4.3 billion to 4.4 billion years ago.

    The findings by two research groups, one in Australia and the other in the US, indicate “liquid water stabilizes early on Earth-type planets,” said geologist Stephen Mojzsis, a member of ...

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  1. The Heat Is On: Asteroid Belt Found Around Nearby Star

    When unusually warm dust was first discovered (1991) around a nearby star, called zeta Leporis, infrared astronomers begun hunting in detail for the heat source. According to the latest research at UCLA, what the star may be undergoing is asteroid and planet formation similar to that of our own early solar system. For infrared astronomers the warm particle halo may reveal more than just a hot cloud. It may reveal a dusty disk that resembles an asteroid belt.

    Michael Jura and Catherine Chen reported their most recent findings at the annual meeting of the American Astronomical Society.

    “We chose to ...

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  1. The First Sulfur Eaters

    Some of the oldest rocks on Earth can be found amid the spiky grass and orange-red dust of Northwestern Australia. While most rocks have been altered over time through geological processes, the Australian rocks have remained relatively unchanged since their inception 3.47 billion years ago. Earlier this year, Yanan Shen of Harvard University, Donald Canfield of Odense University in Denmark, and Roger Buick of the University of Washington announced they found evidence for life in the ancient Australian rocks.

    The scientists found indications of a type of bacteria that consume sulfate and produce sulfide as a waste product. Sulfate-reducing ...

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  1. Test-Tube RNA

    Based on an MIT Whitehead Institute press release

    A new RNA enzyme, or ribozyme, synthesized by David Bartel, Wendy Johnson and colleagues at MIT’s Whitehead Institute for Biomedical Research, opens a door to create a path for the earliest evolution to have happened without either DNA or proteins in the primordial soup. Since first described in the journal Science, the Whitehead ribozyme, or RNA catalyst, has filled in the picture of early chemical evolution and how life might have arisen.

    As highlighted in Sydney Altman’s 1989 Nobel laureate address entitled “RNA World”: “If very primitive life on Earth ...

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  1. NASA’s Global Surveyor Sees Possible Climate Change on Mars

    Based on a Jet Propulsion Laboratory press release

    The planet Mars we know today is a cold, dry, desert world, but suppose the martian climate is changing even now, year to year and decade to decade?

    New observations by NASA’s Mars Global Surveyor spacecraft are expanding understanding of the martian climate and may indicate the climate is changing significantly even today. This suggests even larger climate changes have occurred during the planet’s recent history and may again in its future. The observations were made during a full martian year, 687 Earth days.

    If this is so, Mars might someday ...

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  1. Atmosphere of an Extrasolar Planet Detected for the First Time

    Astronomers have made the first direct detection and chemical analysis of an atmosphere of a planet that exists outside our solar system.

    The planet – HD 209458b – orbits a yellow, Sun-like star that lies 150 light-years away. The star HD 209458 is in the constellation Pegasus, and can be seen with an amateur telescope.

    As the planet passes in front of – or “transits” – its parent star, light rays from the star pass through the planet’s atmosphere. Using NASA’s Hubble Space Telescope, the astronomers analyzed the spectrum of this light and detected the presence of sodium in the ...

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  1. Doubts About ALH84001: The JSC Mars Meteorite Team Responds

    Buseck et al. have “rediscovered” an anaytical method developed in 1947 by Dennis Gabor for defining the morphology of crystals using electron microscopy. Unfortunately, the Buseck et al. paper adds nothing to further the understanding of the issue of life on Mars. It demonstrates that these authors fail to understand the work of Thomas-Keprta et al, 2001 who used a transmission electron microscope to image individual microscopic particles at multiple angles and orientations. From this, the 3-D morphology of the particles could be reconstructed. The technique used by Buseck et al. also uses a transmission electron microscope to image microscopic ...

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  1. Café Methane

    Hydrothermal vents along the mid-ocean ridges have drawn much attention from scientists who study Earth’s extreme environments – and what they may mean for the prospect of life elsewhere in the solar system.

    But in recent years, researchers discovered life also thrives in other, much colder, lightless deep-sea ecosystems. Such habitats are created where faults in ancient sediments allow natural gas (methane) in deeply buried deposits to seep upward to the ocean floor to form methane ices known as gas hydrates.

    These “methane seeps” are found all over the world on continental slopes some 500 to 1,000 meters (1 ...

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  1. Eating Kerogen

    When microorganisms die in ponds of water or in the ocean, they slowly sink to the bottom, forming a thick black sludge. Over time, this sludge becomes buried and compacted by more organisms and layers of mud. If oxygen is left out of the mixture, the organic matter can’t decay and it eventually fossilizes into the material called kerogen.

    Scientists have long believed that kerogen was a carbon ‘sink’ – a place where carbon was trapped and could not be recycled. But recently, a team of researchers led by Steven Petsch of the Woods Hole Oceanographic Institution (WHOI) discovered that ...

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  1. Dedication of the Carl Sagan Center

    The nature of life on Earth and the search for life elsewhere are two sides of the same question – the search for who we are.

    -Carl Sagan

    On Friday, November 9, 2001, on what would have been Carl Sagan’s 67th birthday, the NASA Ames Research Center dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos. The cornerstone for the new Center was unveiled during the dedication ceremony.

    “Carl was an incredible visionary, and now his legacy can be preserved and advanced by a 2lst century research and education laboratory committed to ...

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  1. Evidence of Martian Life Dealt Critical Blow

    Based on an Arizona State University press release

    There may have once been (and perhaps still is) life on Mars, but the evidence for it is barely stirring.

    When, in 1996, a group of NASA researchers presented several lines of evidence for fossil bacteria in a Martian meteorite, a wave of excitement passed through the public and the scientific community alike. Of course, that wave was followed by a storm of controversy.

    Five years of scrutiny and debate over the NASA group’s claims have since brought all but one of their arguments unceremoniously back to Earth. Non-biological processes and contamination ...

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  1. Europe Heads for Mars

    The H.M.S. Beagle set sail from Britain late in the stormy December of 1831, bearing the young naturalist Charles Darwin on a quest to understand the natural history of the farthest lands humans could reach. One hundred and seventy two years later, the UK’s Open and Leicester Universities, together with Astrium, an Aerospace Industry partner, aims to reach a bit farther: to Mars. Beagle 2, a compact, lightweight lander carried on the European Space Agency’s (ESA) Mars Express, will search for signs of life on the red planet.

    The H.M.S. Beagle’s captain, Robert ...

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  1. Why Microbes Matter

    It is difficult to speculate where this new biology may lead. We may learn to apply universal principles of biology to better understand our own type of life and to do such things as develop artificial cells, tissues and organs that might be better suited for certain purposes as compared to those that can be engineered based only on terrestrial principles.

    As a potential location for our second datum of biology, our neighboring planet Mars once again beckons. The possibility that the labeled release experiment (LR), carried to Mars in 1976 aboard the two Viking landers, actually discovered microorganisms is ...

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  1. The Invasion of the Deep-Sea Microbes

    On the deep sea floor, along the margins of diverging plates of ocean crust, communities of microscopic organisms live around hot volcanic vents. These seafloor hydrothermal systems have probably existed on Earth since the oceans first formed, more than four billion years ago. The microscopic life around the vents may also have an ancient heritage — genetic comparisons suggest that modern vent microbes are close kin to the earliest forms of life on Earth. These regions are therefore of special interest to astrobiologists, who study the geology, chemistry, and biology of hydrothermal vents to better understand how Earth’s early biosphere ...

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  1. Glass Munchers Under the Sea

    A team of researchers recently announced that they have found the deepest-living microbes on the planet. These bacteria eat into rock at the bottom of the sea floor, some burrowing down as far as 500 meters (1,640 feet), although most of the microbial activity seems to be in the upper 300 meters (984 feet) of the ocean crust.

    “We’ve documented how extensive these microscopic organisms are eating into volcanic rock, leaving worm-like tracks that look like someone has drilled their way in,” says one of the paper’s co-authors, Hubert Staudigel of Scripps Institution of Oceanography at ...

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