Recently in the Astrogeology Category

Is Iron A Biological Element?

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and a half billion years ago.

Planet Earth is situated in what astronomers call the Goldilocks Zone -- a sweet spot in a solar system where a planet's surface temperature is neither too hot nor too cold.

Planets with volcanic activity are considered better candidates for life than worlds without such heated internal goings-on.

Understanding the collisional properties of ice is important for understanding both the early stages of planet formation and the evolution of planetary ring systems.

We present an inversion method based on Bayesian analysis to constrain the interior structure of terrestrial exoplanets, in the form of chemical composition of the mantle and core size.

How do you make an Earth-like planet? The "test kitchen" of Earth has given us a detailed recipe, but it wasn't clear whether other planetary systems would follow the same formula.

A new study is helping to answer a longstanding question that has recently moved to the forefront of earth science: Did our planet make its own water through geologic processes, or did water come to us via icy comets from the far reaches of the solar system?

Applications due: February 15, 2013

In this intense multidisciplinary summer course, June 9 - July 12, explore the coevolution of the Earth and its biosphere, with emphasis on how microbial processes affect the environment and leave imprints on the rock record. Participants get hands-on experience in cutting-edge geobiological techniques including molecular biology, bioinformatics, geochemistry, petrology and sedimentology, and work in research groups to solve relevant questions. The course will involve a field trip to the Great Salt Lake and southern Wyoming. Lab work will be conducted at the Colorado School of Mines in Golden, Colorado, USC/Caltech/JPL in the Los Angeles area and the USC Wrigley Institute on Catalina Island. The 2013 course is open to students and researchers at any level, although we give preference to graduate students in their early to mid years of study.

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A new study, supported in part by the NASA Astrobiology Institute, suggests that meteorites and their parent asteroids are the most-likely sources of water on Earth. The research led by the Carnegie Institution for Science's Conel Alexander indicates that these rocks from space were the sources of early Earth's volatile elements -- which include hydrogen, nitrogen, and carbon -- and possibly organic material. Understanding if and how volatile elements were delivered to the early Earth is important in determining the origins of both water and life on our planet. This work was partially funded by NASA Cosmochemistry, the NASA Astrobiology Institute, Carnegie Institution of Canada, the Natural Sciences and Engineering Research Council of Canada, the W.M. Keck Foundation, and the UK Cosmochemical Analysis Network. [Source: NAI]

When life began on Earth, iron may have done the job of magnesium, making life possible.

On the periodic table of the elements, iron and magnesium are far apart. But new evidence discovered by NAI's team at the Georgia Institute of Technology suggests that three billion years ago, iron did the job magnesium does today in helping Ribonucleic acid (RNA), a molecule essential for life, assume the molecular shapes necessary for biology.

The results of the study were published online on May 31, 2012 in the journal PLoS ONE.

There is considerable evidence that the evolution of life passed through an early stage when RNA played a more central role, doing the jobs of DNA and protein before they appeared. During that time, more than three billion years ago, the environment lacked oxygen but had lots of available iron.

"One of the greatest challenges in astrobiology is understanding how life began on Earth billions of years ago when the environment was very different than it is today," said Carl Pilcher, director of the Astrobiology Institute at NASA's Ames Research Center, Moffett Field, Calif. "This study shows us how conditions on early Earth may have been conducive to the development of life."

In the new study, researchers from the Georgia Institute of Technology, Atlanta, used experiments and numerical calculations to show that under early Earth conditions, with little oxygen around, iron can substitute for magnesium in RNA, enabling it to assume the shapes it needs to catalyze life's chemical reactions. In fact, it catalyzed those reactions better with iron than with magnesium.