Posts about astrobiology

Apply to be an Astronaut

Are you looking to change jobs? NASA is seeking outstanding scientists, engineers (job announcement closed so broken link removed), and other talented professionals to carry forward the great discovery process that its mission demands. Creativity. Ambition. Teamwork. A sense of daring. Curiosity. That’s what it takes to join NASA, one of the best places to work in the Federal Government.

photo of astronaut's faceplate reflecting earth

The National Aeronautics and Space Administration (NASA) has a need for Astronaut Candidates to support the International Space Station Program and future deep space exploration activities.

In 1959 NASA selected its first group of 7 astronaut candidates. Since then 20 additional classes have been selected; bringing the total number of astronaut candidates to 330.

The astronauts of the 21st century will continue to work aboard the International Space Station in cooperation with our international partners; help to build and fly a new NASA vehicle, the Orion Multi-Purpose Crew Vehicle (MPCV) designed for human deep space exploration; and further NASA’s efforts to partner with industry to provide a commercial capability for space transportation to the space station.

NASA is in the process of identifying possible near-Earth asteroids to explore with the goal of visiting an asteroid in 2025. With that goal, and keeping in mind that the plan is to send a robotic precursor mission to the asteroid approximately five years before humans arrive, NASA will need to select the first set of targets to explore within the next decade.

Requirement include: Applicants for the Astronaut Candidate Program must meet the basic education requirements for NASA engineering and scientific positions, specifically: successful completion of standard professional curriculum in an accredited college or university leading to at least a bachelor’s degree with major study in an appropriate field of engineering, biological science, physical science, or mathematics.

Related: NASA Robotics AcademyNASA’s Mars Curiosity RoverAstronaut Drops a Hammer and Feather on the Moon

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New Analysis of Primordial Soup Experiment Half a Century Later

Open access paper: Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples.

The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment.

The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

Related: All present-day Life on Earth Has A Single AncestorLife Untouched by the SunAmazing Designs of LifeAlbert Einstein, Marylin Monroe Hybrid Image

Changing Life as We Know It

Update: Independent researchers find no evidence for arsenic life in Mono Lake

NASA has made a discovery that changes our understanding of the very makeup of life itself on earth. I think my favorite scientific discipline name is astrobiology. NASA pursues a great deal of this research not just out in space but also looking at earth based life. Their astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.

photo of Felisa Wolfe-Simon

Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

Researchers conducting tests in the harsh, but beautiful (see photo), environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.” This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.

In science such huge breakthroughs are not just excepted without debate, however, which is wise.

Thriving on Arsenic:

In other words, every experiment Wolfe-Simon performed pointed to the same conclusion: GFAJ-1 can substitute arsenic for phosphorus in its DNA. “I really have no idea what another explanation would be,” Wolfe-Simon says.

But Steven Benner, a distinguished fellow at the Foundation for Applied Molecular Evolution in Gainesville, FL, remains skeptical. If you “replace all the phosphates by arsenates,” in the backbone of DNA, he says, “every bond in that chain is going to hydrolyze [react with water and fall apart] with a half-life on the order of minutes, say 10 minutes.” So “if there is an arsenate equivalent of DNA in that bug, it has to be seriously stabilized” by some as-yet-unknown mechanism.

It is sure a great story if it is true though. Other scientists will examine more data and confirm or disprove the claims.

“We know that some microbes can breathe arsenic, but what we’ve found is a microbe doing something new — building parts of itself out of arsenic,” said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team’s lead scientist. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?”
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