Wednesday, November 23, 2011

NASA's TRMM Satellite Sees Deadly Tornadic Thunderstorms in Southeastern U.S.

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Tornadoes are expected to accompany severe storms in the springtime in the U.S., but this time of year they also usually happen. When a line of severe thunderstorms associated with a cold front swept through the U.S. southeast on Nov. 16, TRMM collected rainfall data on the dangerous storms from space.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite flew over the southeastern United States on November 16, 2011 at 2310 UTC (6:10 p.m. EST) when tornadoes were occurring with a line of thunderstorms that stretched from western Florida north through North Carolina. At least six deaths were caused by one of these tornadoes that destroyed three homes near Rock Hill, South Carolina.

Typically in the fall, the transition from warm air to cooler air occurs as Canadian cold air moves down into the U.S. The combination of a strong cold front with warm, moist air in its path enables the creation of strong to severe storms at this time of year.

TRMM data was used to create a rainfall analysis of the line of severe thunderstorms associated with the cold front. The analysis showed that the area of moderate to very heavy rainfall (falling at more than 2 inches or 50 mm per hour) with this frontal system was only located in a narrow line. In addition to heavy rain and some tornadoes, the strong cold front brought winds gusting over 30 mph, and a temperature drop of as much as 20 degrees as the front passed.

TRMM rainfall imagery is created at the NASA Goddard Space Flight Center in Greenbelt, Md. To create the images, rain rates in the center swaths are taken from the TRMM Precipitation Radar (PR), a unique space-borne precipitation radar, while rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS) to form a complete picture of the rainfall in a storm or storm system like this one.

Data captured at the same time with TRMM's Precipitation Radar (PR) were used to create a three dimensional look at the line of severe storms. That 3-D image shows the vertical structure or height of the thunderstorms. The higher the cloud tops go, the stronger the storm. Strong updrafts had pushed precipitation within some of these storms to heights of 9.3 miles (15 kilometers).

According to USA Today tornadoes were reported in four states from that line of thunderstorms. Alabama, Mississippi, Louisiana and South Carolina all had reported tornadoes, and dozens of buildings and homes were damaged. The line of severe weather also took down trees and power lines leaving many without electricity.

The Tropical Rainfall Measuring Mission is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall.

For more information visit http://www.nasa.gov/topics/earth/features/Tornadic-Storms.html

Tuesday, November 22, 2011

ESA To Collaborate with NASA on Solar Science Mission

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Solar Orbiter will venture closer to the Sun than any previous mission. The spacecraft will also carry advanced instrumentation that will help untangle how activity on the sun sends out radiation, particles and magnetic fields that can affect Earth's magnetic environment, causing aurora, or potentially damaging satellites, interfering with GPS communications or even Earth's electrical power grids.

"Solar Orbiter will use multiple gravity assists from Venus to tilt its orbit until it can see the poles of the Sun, and that's never been done before," said Chris St. Cyr, NASA's project scientist for Solar Orbiter at Goddard. "A full view of the solar poles will help us understand how the sun's magnetic poles reverse direction every 11 years, causing giant eruptions and flares, called space weather, that can affect the rest of the solar system."

Being so close to the sun also means that the Solar Orbiter will stay over a given area of the solar surface for a longer time, allowing the instruments to track the evolution of sunspots, active regions, coronal holes and other solar activity far longer than has been done before.

Solar Orbiter is also designed to make major breakthroughs in our understanding of how the sun generates and propels the flow of particles in which the planets are bathed, known as the solar wind. Solar activity and solar eruptions create strong perturbations in this wind, triggering spectacular auroral displays on Earth and other planets. Solar Orbiter will be close enough to the sun to both observe the details of how the solar wind is accelerated off the sun and to sample the wind shortly after it leaves the surface.

The mission's launch is planned for 2017 from Cape Canaveral, Florida aboard a NASA-provided launch vehicle. Solar Orbiter will be placed into an elliptical orbit around the sun. Its closest approach will be near the orbit of Mercury, 75% of the distance between Earth and the sun – some 21,000,000 miles away from the sun's surface.

For more information visit http://www.nasa.gov/mission_pages/sunearth/news/ESA-SolarOrbiter.html

Friday, November 18, 2011

NASA's Hubble Confirms That Galaxies Are the Ultimate Recyclers

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New observations by NASA's Hubble Space Telescope are expanding astronomers' understanding of the ways in which galaxies continuously recycle immense volumes of hydrogen gas and heavy elements. This process allows galaxies to build successive generations of stars stretching over billions of years.

This ongoing recycling keeps some galaxies from emptying their "fuel tanks" and stretches their star-forming epoch to over 10 billion years.

This conclusion is based on a series of Hubble Space Telescope observations that flexed the special capabilities of its Cosmic Origins Spectrograph (COS) to detect gas in the halo of our Milky Way and more than 40 other galaxies. Data from large ground-based telescopes in Hawaii, Arizona and Chile also contributed to the studies by measuring the properties of the galaxies.

Astronomers believe that the color and shape of a galaxy is largely controlled by gas flowing through an extended halo around it. The three studies investigated different aspects of the gas-recycling phenomenon.

The results are being published in three papers in the November 18 issue of Science magazine. The leaders of the three studies are Nicolas Lehner of the University of Notre Dame in South Bend, Ind.; Jason Tumlinson of the Space Telescope Science Institute in Baltimore, Md.; and Todd Tripp of the University of Massachusetts at Amherst.

The COS observations of distant stars demonstrate that a large mass of clouds is falling through the giant halo of our Milky Way, fueling its ongoing star formation. These clouds of hot hydrogen reside within 20,000 light-years of the Milky Way disk and contain enough material to make 100 million suns. Some of this gas is recycled material that is continually being replenished by star formation and the explosive energy of novae and supernovae, which kicks chemically enriched gas back into the halo.

The COS observations also show halos of hot gas surrounding vigorous star-forming galaxies. These halos, rich in heavy elements, extend as much as 450,000 light-years beyond the visible portions of their galactic disks. The amount of heavy-element mass discovered far outside a galaxy came as a surprise. COS measured 10 million solar masses of oxygen in a galaxy's halo, which corresponds to about one billion solar masses of gas -- as much as in the entire space between stars in a galaxy’s disk.

Researchers also found that this gas is nearly absent from galaxies that have stopped forming stars. In these galaxies, the “recycling” process ignites a rapid firestorm of star birth which can blow away the remaining fuel, essentially turning off further star-birth activity.

This is evidence that gas pushed out of a galaxy, rather than pulled in from intergalactic space, determine a galaxy's fate."

The Hubble observations demonstrate that those galaxies forming stars at a very rapid rate, perhaps a hundred solar masses per year, can drive two-million-degree gas very far out into intergalactic space at speeds of up to two million miles per hour. That's fast enough for the gas to escape forever and never refuel the parent galaxy.

While hot gas "winds" from galaxies have been known for some time, the new COS observations reveal that hot outflows extend to much greater distances than previously thought and can carry a tremendous amount of mass out of a galaxy. Some of the hot gas is moving more slowly and could eventually be recycled. The observations show how gas-rich star-forming spiral galaxies can evolve to elliptical galaxies that no longer have star formation.

The light emitted by this hot plasma is invisible, so the researchers used COS to detect the presence of the gas by the way it absorbs certain colors of light from background quasars. Quasars are the brightest objects in the universe and are the brilliant cores of active galaxies that contain active central black holes. The quasars serve as distant lighthouse beacons that shine through the gas-rich "fog" of hot plasma encircling galaxies. At ultraviolet wavelengths, COS is sensitive to the presence of heavy elements, such as nitrogen, oxygen, and neon. COS's high sensitivity allows many galaxies to be studied that happen to lie in front of the much more distant quasars. The ionized heavy elements are markers for estimating how much mass is in a galaxy's halo.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

For more information visit http://www.nasa.gov/mission_pages/hubble/science/recyclers.html

Idressonline conducting Thanksgiving Sale with special offers

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Friday, November 11, 2011

NASA Develops Super-Black Material That Absorbs Light Across Multiple Wavelength Bands

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NASA engineers have produced a material that absorbs on average more than 99 percent of the ultraviolet, visible, infrared, and far-infrared light that hits it -- a development that promises to open new frontiers in space technology.

The team of engineers at NASA's Goddard Space Flight Center in Greenbelt, Md., reported their findings recently at the SPIE Optics and Photonics conference, the largest interdisciplinary technical meeting in this discipline. The team has since reconfirmed the material's absorption capabilities in additional testing, said John Hagopian, who is leading the effort involving 10 Goddard technologists.

"The reflectance tests showed that our team had extended by 50 times the range of the material’s absorption capabilities. Though other researchers are reporting near-perfect absorption levels mainly in the ultraviolet and visible, our material is darn near perfect across multiple wavelength bands, from the ultraviolet to the far infrared," Hagopian said. "No one else has achieved this milestone yet."



The nanotech-based coating is a thin layer of multi-walled carbon nanotubes, tiny hollow tubes made of pure carbon about 10,000 times thinner than a strand of human hair. They are positioned vertically on various substrate materials much like a shag rug. The team has grown the nanotubes on silicon, silicon nitride, titanium, and stainless steel, materials commonly used in space-based scientific instruments. (To grow carbon nanotubes, Goddard technologist Stephanie Getty applies a catalyst layer of iron to an underlayer on silicon, titanium, and other materials. She then heats the material in an oven to about 1,382 degrees Fahrenheit. While heating, the material is bathed in carbon-containing feedstock gas.)

The tests indicate that the nanotube material is especially useful for a variety of spaceflight applications where observing in multiple wavelength bands is important to scientific discovery. One such application is stray-light suppression. The tiny gaps between the tubes collect and trap background light to prevent it from reflecting off surfaces and interfering with the light that scientists actually want to measure. Because only a small fraction of light reflects off the coating, the human eye and sensitive detectors see the material as black.

In particular, the team found that the material absorbs 99.5 percent of the light in the ultraviolet and visible, dipping to 98 percent in the longer or far-infrared bands. "The advantage over other materials is that our material is from 10 to 100 times more absorbent, depending on the specific wavelength band," Hagopian said.

"We were a little surprised by the results," said Goddard engineer Manuel Quijada, who co-authored the SPIE paper and carried out the reflectance tests. "We knew it was absorbent. We just didn't think it would be this absorbent from the ultraviolet to the far infrared."


If used in detectors and other instrument components, the technology would allow scientists to gather hard-to-obtain measurements of objects so distant in the universe that astronomers no longer can see them in visible light or those in high-contrast areas, including planets in orbit around other stars, Hagopian said. Earth scientists studying the oceans and atmosphere also would benefit. More than 90 percent of the light Earth-monitoring instruments gather comes from the atmosphere, overwhelming the faint signal they are trying to retrieve.

Currently, instrument developers apply black paint to baffles and other components to help prevent stray light from ricocheting off surfaces. However, black paints absorb only 90 percent of the light that strikes it. The effect of multiple bounces makes the coating’s overall advantage even larger, potentially resulting in hundreds of times less stray light.

In addition, black paints do not remain black when exposed to cryogenic temperatures. They take on a shiny, slightly silver quality, said Goddard scientist Ed Wollack, who is evaluating the carbon-nanotube material for use as a calibrator on far-infrared-sensing instruments that must operate in super-cold conditions to gather faint far-infrared signals emanating from objects in the very distant universe. If these instruments are not cold, thermal heat generated by the instrument and observatory, will swamp the faint infrared they are designed to collect.

Black materials also serve another important function on spacecraft instruments, particularly infrared-sensing instruments, added Goddard engineer Jim Tuttle. The blacker the material, the more heat it radiates away. In other words, super-black materials, like the carbon nanotube coating, can be used on devices that remove heat from instruments and radiate it away to deep space. This cools the instruments to lower temperatures, where they are more sensitive to faint signals.

To prevent the black paints from losing their absorption and radiative properties at long wavelengths, instrument developers currently use epoxies loaded with conductive metals to create a black coating. However, the mixture adds weight, always a concern for instrument developers. With the carbon-nanotube coating, however, the material is less dense and remains black without additives, and therefore is effective at absorbing light and removing heat. "This is a very promising material," Wollack said. "It's robust, lightweight, and extremely black. It is better than black paint by a long shot."

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For more information visit http://www.nasa.gov/topics/technology/features/super-black-material.html

Tuesday, November 8, 2011

Herschel Finds Oceans of Water in Disk of Nearby Star

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Using data from the Herschel Space Observatory, astronomers have detected for the first time cold water vapor enveloping a dusty disk around a young star. The findings suggest that this disk, which is poised to develop into a solar system, contains great quantities of water, suggesting that water-covered planets like Earth may be common in the universe. Herschel is a European Space Agency mission with important NASA contributions.

Scientists previously found warm water vapor in planet-forming disks close to a central star. Evidence for vast quantities of water extending out into the cooler, far reaches of disks where comets take shape had not been seen until now. The more water available in disks for icy comets to form, the greater the chances that large amounts eventually will reach new planets through impacts.

"Our observations of this cold vapor indicate enough water exists in the disk to fill thousands of Earth oceans," said astronomer Michiel Hogerheijde of Leiden Observatory in The Netherlands. Hogerheijde is the lead author of a paper describing these findings in the Oct. 21 issue of the journal Science.

The star with this waterlogged disk, called TW Hydrae, is 10 million years old and located about 175 light-years away from Earth, in the constellation Hydra. The frigid, watery haze detected by Hogerheijde and his team is thought to originate from ice-coated grains of dust near the disk's surface. Ultraviolet light from the star causes some water molecules to break free of this ice, creating a thin layer of gas with a light signature detected by Herschel's Heterodyne Instrument for the Far-Infrared, or HIFI.

"These are the most sensitive HIFI observations to date," said Paul Goldsmith, NASA project scientist for the Herschel Space Observatory at the agency's Jet Propulsion Laboratory in Pasadena, Calif. "It is a testament to the instrument builders that such weak signals can be detected."
TW Hydrae is an orange dwarf star, somewhat smaller and cooler than our yellow-white sun. The giant disk of material that encircles the star has a size nearly 200 times the distance between Earth and the sun. Over the next few million years, astronomers believe matter within the disk will collide and grow into planets, asteroids and other cosmic bodies. Dust and ice particles will assemble as comets.

As the new solar system evolves, icy comets are likely to deposit much of the water they contain on freshly created worlds through impacts, giving rise to oceans. Astronomers believe TW Hydrae and its icy disk may be representative of many other young star systems, providing new insights on how planets with abundant water could form throughout the universe.

For more information visit http://www.nasa.gov/mission_pages/herschel/news/herschel20111020.html

Monday, November 7, 2011

A Day for Recharging: Green Flight Challenge Competition, Day Three

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At the CAFE Green Flight Challenge, sponsored by Google, the competing electric aircraft are completing battery recharging today in preparation for their speed challenge tomorrow. Many of the team members are away from the CAFE campus, doing some sightseeing and catching up on other business. Everything is much more relaxed today here in Santa Rosa, Calif., at the site of this NASA Centennial Challenges event.

CAFE has more than 80 volunteers helping out with the competition. They can be seen around the campus, wearing Green Flight Challenge shirts. They've been quite the local heroes.

The daily briefing was at 11 a.m. EDT. A big concern for tomorrow's challenge is the weather, which looks to be a bit questionable when the speed test is planned, so CAFE wants to get the planes off as soon as they can tomorrow morning. A suggestion was made to have the pilots' briefing at 10:30 a.m. EDT in order to expedite the planes taking off.

Safety and security measures were reviewed and particular emphasis was placed on the no-smoking requirement. (This is fire season in California and the area is quite dry and a fire would be a bad thing to deal with.

Everyone was also cautioned about the poisonous black widow and brown recluse spiders in the area -- adding another note of excitement as the next competition nears.

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For more information visit http://www.nasa.gov/topics/technology/centennial/gfc_third_day.html