NAI Research Archive

Meteorites Most Likely Source of Earth's Water

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.

A New Look at the Martian Blueberries

Scientists at Syracuse University - part of NAI's team at RPI - report new information about the history of water on Mars in the current issue of Planetary and Space Science. Focused on the hematite spherules known as the "blueberries" discovered by NASA's Mars Exploration Rover Opportunity in 2004, the study suggests that ages measured using the relative abundances of uranium, thorium, and helium in the blueberries could yield the time that has passed since water last wetted the sediments.

New Insight into Star Formation

Using combined data from a trio of orbiting X-ray telescopes, including NASA's Chandra X-ray Observatory and the Japan-led Suzaku satellite, astronomers have obtained a rare glimpse of the powerful phenomena that accompany a still-forming star. A new study based on these observations indicates that intense magnetic fields drive torrents of gas into the stellar surface, where they heat large areas to millions of degrees. X-rays emitted by these hot spots betray the newborn star's rapid rotation. For more, including an animation of these X-ray hot spots, read the press release from NASA's Goddard Space Flight Center.

Two Stars and One Planet

A team of Penn State University astronomers has obtained very precise measurements of a pair of stars that are orbited by a planet – like the binary system of the fictional planet Tatooine from the movie Star Wars. The orbits of the stars and planet in the system, named Kepler-16, are aligned so that they eclipse or transit each other when observed from Earth. The new measurements will aid astronomers in understanding how stars and planetary systems form. The data was obtained with the Hobby-Eberly Telescope at McDonald Observatory and provides an important independent test of a new technique for measuring masses from Kepler spacecraft data.

A preprint of the paper is online at http://arxiv.org/abs/1205.0259. Funding for this research was provided by the Center for Exoplanets and Habitable Worlds, the NASA Astrobiology Institute, the Penn State Astrobiology Research Center, and the National Science Foundation.

Newfound Gene Aids Survival in Extreme Environments

With support from the NASA Astrobiology Program, researchers at the Massachusetts Institute of Technology (MIT) have discovered a new bacterial gene that could provide clues about how life survives in some of Earth’s most extreme environments.

The gene codes for a protein, named HpnR, that is responsible for producing bacterial lipids known as 3-methylhopanoids. These lipids could help prepare nutrient-starved microbes to make a sudden appearance in nature when conditions are favorable. It allows the organisms to survive in extreme, oxygen-depleted environments until food — such as methane and the oxygen needed to metabolize it — become available.

The lipid produced by the HpnR protein may also be used as a biomarker in rock layers to identify dramatic changes in oxygen levels throughout Earth’s history.

"The thing that interests us is that this could be a window into the geologic past," says MIT postdoc Paula Welander, who led the research. "In the geologic record, many millions of years ago, we see a number of mass extinction events where there is also evidence of oxygen depletion in the ocean. It's at these key events, and immediately afterward, where we also see increases in all these biomarkers as well as indicators of climate disturbance. It seems to be part of a syndrome of warming, ocean deoxygenation and biotic extinction. The ultimate causes are unknown."

The research was supported by the NASA Astrobiology Program via the NASA Postdoctoral Program, and was completed under the guidance of NASA Astrobiology Institute Principle Investigator, Roger Summons, at the Massachusetts Institute of Technology (MIT).

The paper, “Discovery, taxonomic distribution, and phenotypic characterization of a gene required for 3-methylhopanoid production,” was published on July 23, 2012, in the Proceedings of the National Academy of Science (PNAS) under lead author Paula V. Welander.