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Extreme planet makeover interactive feature. Image credit: NASA/JPL-Caltech 

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An artist's rendering of the lunar core as identified in new findings by a NASA-led research team. (NASA/MSFC/Renee Weber) 

A close-up view of the Passive Seismic Experiment, a component of the Apollo Lunar Surface Experiments Package (ALSEP) which was deployed on the Moon by the Apollo 14 astronauts during their first extravehicular activity (EVA-1). (NASA/JSC) 

Renee Weber. (NASA/MSFC)

State-of-the-art seismological techniques applied to Apollo-era data suggest our moon has a core similar to Earth's. 

Uncovering details about the lunar core is critical for developing accurate models of the moon's formation. The data sheds light on the evolution of a lunar dynamo -- a natural process by which our moon may have generated and maintained its own strong magnetic field. 

The team's findings suggest the moon possesses a solid, iron-rich inner core with a radius of nearly 150 miles and a fluid, primarily liquid-iron outer core with a radius of roughly 205 miles. Where it differs from Earth is a partially molten boundary layer around the core estimated to have a radius of nearly 300 miles. The research indicates the core contains a small percentage of light elements such as sulfur, echoing new seismology research on Earth that suggests the presence of light elements -- such as sulfur and oxygen -- in a layer around our own core. 

The researchers used extensive data gathered during the Apollo-era moon missions. The Apollo Passive Seismic Experiment consisted of four seismometers deployed between 1969 and 1972, which recorded continuous lunar seismic activity until late-1977. 

"We applied tried and true methodologies from terrestrial seismology to this legacy data set to present the first-ever direct detection of the moon's core," said Renee Weber, lead researcher and space scientist at NASA's Marshall Space Flight Center in Huntsville, Ala. 

In addition to Weber, the team consisted of scientists from Marshall; Arizona State University; the University of California at Santa Cruz; and the Institut de Physique du Globe de Paris in France. Their findings are published in the online edition of the journal Science. 

The team also analyzed Apollo lunar seismograms using array processing, techniques that identify and distinguish signal sources of moonquakes and other seismic activity. The researchers identified how and where seismic waves passed through or were reflected by elements of the moon's interior, signifying the composition and state of layer interfaces at varying depths. 

Although sophisticated satellite imaging missions to the moon made significant contributions to the study of its history and topography, the deep interior of Earth's sole natural satellite remained a subject of speculation and conjecture since the Apollo era. Researchers previously had inferred the existence of a core, based on indirect estimates of the moon's interior properties, but many disagreed about its radius, state and composition. 

Hubble Snaps Image of Space Oddity

› Print resolution image (3.9 Mb)Credit: NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo Team
In this image by NASA's Hubble Space Telescope, an unusual, ghostly green blob of gas appears to float near a normal-looking spiral galaxy.

Crystals of human hematopoietic prostaglandin D synthase (H-PGDS) grown under terrestrial (a) and microgravity (b) conditions. In the microgravity experiment plate-like crystals were grown with good morphology. Scale bar corresponds to 100 μm. (Dr. Yoshihiro Urade, Osaka Bioscience Institute)

Data from STS-115 S. typhimuriumexperiments. SEM of spaceflight bacteria showing -- white areas -- the formation of an extracellular matrix and associated cellular aggregation of space flight cells. Magnification: X3.500. (The Biodesign Institute, Arizona State University)The new year is here, and along with it a new era of utilization for research and technology begins for the completed International Space Station. The orbiting laboratory shifts focus in 2011 from finalizing construction efforts to full-scale use of the facility for scientific investigation and technological advances.

Mark Uhran, assistant associate administrator for the International Space Station at NASA Headquarters, kicked off the year at the 49th AIAA Meeting speaking on the topic, Positioning the International Space Station for the Utilization Era.

"Full-scale ISS utilization will re-boot the spacecraft for the purposes for which it was originally designed -- scientific research, applications development, technological demonstration and industrial growth," Uhran says.

With benefits from research conducted under microgravity conditions already being realized, the NASA authorization act of 2010 extends the life of the space station to 2020. Accomplishments during the second decade of continuous human life, work and research on the station will depend upon the global-market impact of station-based research and development, as well as continued government programmatic support.

The past 25 years of microgravity-based research, on earlier missions and during station assembly, can be viewed as a survey phase. Although it can take a long time for the full application of research results in our daily lives, early space research has already yielded important progress and advances for industry and health here on Earth. In his AIAA paper, Uhran reviews five specific examples of notable discoveries and their benefits:

Andromeda, shown here, is one of two distant galaxies where astronomers recently searched for diffuse interstellar bands (DIBs). If DIBs were found when looking in a straight line from Earth to a star in the galaxy, the star is circled. Bigger circles indicate stronger DIBs. An "x" means no DIBS were observed. The colors in the insets correspond to wavelengths of the spectrum: blue for UV, green for visible light, and red for infrared.Credit: M31 image by Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF. Insets from Nick Cox, Institute for Astronomy, K.U. Leuven.
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The Triangulum Galaxy, located nearly 3 million light years from Earth, is another far galaxy where researchers have found diffuse interstellar bands (DIBs). The detailed observations needed to see DIBs along a straight line from Earth to an individual star in such a distant galaxy stretch the limits of even the largest telescopes. Credit: NASA/Swift Science Team/Stefan Immler
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