NASA Investigating the Life of Comet ISON

After several days of continued observations, scientists continue to work to determine and to understand the fate of Comet ISON: There's no doubt that the comet shrank in size considerably as it rounded the sun and there's no doubt that something made it out on the other side to shoot back into space. The question remains as to whether the bright spot seen moving away from the sun was simply debris, or whether a small nucleus of the original ball of ice was still there. Regardless, it is likely that it is now only dust.  

Comet ISON, which began its journey from the Oort Cloud some 3 million years ago, made its closest approach to the sun on Nov. 28, 2013. The comet was visible in instruments on NASA's Solar Terrestrial Relations Observatory, or STEREO, and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, via images called coronagraphs. Coronagraphs block out the sun and a considerable distance around it, in order to better observe the dim structures in the sun's atmosphere, the corona. As such, there was a period of several hours when the comet was obscured in these images, blocked from view along with the sun. During this period of time, NASA's Solar Dynamics Observatory could not see the comet, leading many scientists to surmise that the comet had disintegrated completely. However, something did reappear in SOHO and STEREO coronagraphs some time later – though it was significantly less bright.

Whether that spot of light was merely a cloud of dust that once was a comet, or if it still had a nucleus – a small ball of its original, icy material – intact, is still unclear. It seems likely that as of Dec. 1, there was no nucleus left. By monitoring its changes in brightness over time, scientists can estimate whether there's a nucleus or not, but our best chance at knowing for sure will be if the Hubble Space Telescope makes observations later in December 2013.

Regardless of its fate, Comet ISON did not disappoint researchers. Over the last year, observatories around the world and in space gathered one of the largest sets of comet observations of all time, which should provide fodder for study for years to come. The number of space-based, ground-based, and amateur observations were unprecedented, with twelve NASA space-based assets observing over the past year.

Related Links:

For more information on Comet ISON: www.nasa.gov/ison

To download recent ISON imagery: http://svs.gsfc.nasa.gov/Gallery/CometISON.html

Legless geckos slither using skin ridges

A belly carpeted in flattened ridges may help legless lizards slither. Some geckos have only two tiny tabs for legs, so they wriggle and glide like snakes.

These geckos may propel themselves with microscopic corduroy-like ribs on their skin, Marlene Spinner of the University of Kiel in Germany and colleagues suggest October 9 in the Proceedings of the Royal Society B. Unlike geckos with legs, which owe their sticky grip to spines on the skin, the flap-footed lizard Lialis jicari is spine-free where skin skims the ground.

Instead, the reptile carries blunt nubs on the chin and rows of orderly ripples on the stomach, the team discovered by examining freshly shed skin under a microscope. The skin ribs could reduce friction as the animals slide forward.

Source: www.sciencenews.org

Voyager's view

It’s finally official: Voyager 1 has become the first human-made object to enter interstellar space, mission scientists report September 12 in Science. On August 25, 2012, the scientists say, Voyager 1 exited a giant invisible bubble called the heliosphere that is inflated by a torrent of subatomic particles spewing from the sun. Now the probe is surrounded almost exclusively by particles produced by other stars. But whether it’s correct to say that the probe has left the solar system depends on how you define the solar system. “From my perspective, Voyager is nowhere near the edge of the solar system,” says planetary scientist Hal Levison of the Southwest Research Institute in Boulder, Colo. The sun continues to exert gravitational dominance out to hundreds of times the distance of Voyager 1 from the sun, where trillions of icy pebbles, boulders and comets orbit. In the last 36 years, Voyager has traveled an impressive 25.4 billion kilometers, but it still has a long way to go to unambiguously depart the solar system.

Source: www.sciencenews.org

A beacon illuminates a key Alzheimer's protein

By Laura Sanders

Web edition: September 18, 2013

Deep within the living brain, a newly created beacon can illuminate hidden signs of Alzheimer’s disease. Recent work has focused on detecting amyloid, a sticky substance that builds up in the brains of people living with Alzheimer’s. But until now, clinicians lacked a good way to see amyloid’s co-conspirator, the protein called tau. Tangles of a harmful form of tau pile up inside the brains of people with Alzheimer’s disease and several other dementias.

Masahiro Maruyama of the National Institute of Radiological Sciences in Japan and colleagues report September 18 in Neuron that a class of molecules can latch on to tau tangles. When linked to radioactive carbon, these molecules serve as beacons that illuminate tau during PET scans. Scientists know from work with cadavers that the hippocampus harbors tau as Alzheimer’s disease progresses. The new imaging tool will help scientists diagnose and study Alzheimer’s disease and other disorders marked by tau accumulation in living people, the researchers write.

Source: www.sciencenews.org

Antares rocket makes its maiden voyage into space

Orbital Sciences' Antares rocket had its first successful launch today, carrying a mock cargo ship into orbit before the rocket burned up in the atmosphere. It comes after two delays, for both weather and mechanical failure, but resulted in a strong showing for the Antares' two-stage booster engine, which utilizes a combination of liquid and solid fuels. Once testing is complete, the rocket is expected to take over resupply and crew launches to the International Space Station. The dummy cargo ship, which weighed over four tons, included three small Phonesat satellites as part of a NASA research experiment, as well as a larger Dove-1 satellite carried on behalf of telecom company Cosmogia.

It's part of a longterm shift at NASA from public missions to private contracts, which has also seen billion-dollar contracts for Elon Musk's SpaceX project project and a gradual phase-out of NASA's own space shuttle project. As one Nasa administrator told Space.com, "This is the culmination of a plan that we've been on for several years." With this successful launch behind them, Orbital Sciences is planning subsequent launches every three to six months, with two more scheduled for 2013 and at least one more mock-launch before they start ferrying actual cargo.