NASA's Spitzer Finds Galaxy With Split Personality

While some galaxies are rotund and others are slender disks like our spiral Milky Way, new observations from NASA's Spitzer Space Telescope show that the Sombrero galaxy is both.The galaxy, which is a round elliptical galaxy with a thin disk embedded inside, is one of the first known to exhibit characteristics of the two different types. The findings will lead to a better understanding of galaxy evolution, a topic still poorly understood.

"The Sombrero is more complex than previously thought," said Dimitri Gadotti of the European Southern Observatory in Chile and lead author of a new paper on the findings appearing in the Monthly Notices of the Royal Astronomical Society."The only way to understand all we know about this galaxy is to think of it as two galaxies, one inside the other."

The Sombrero galaxy, also known as NGC 4594, is located 28 million light-years away in the constellation Virgo.From our viewpoint on Earth, we can see the thin edge of its flat disk and a central bulge of stars, making it resemble a wide-brimmed hat. Astronomers do not know whether the Sombrero's disk is shaped like a ring or a spiral, but agree it belongs to the disk class.

"Spitzer is helping to unravel secrets behind an object that has been imaged thousands of times," said Sean Carey of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena."It is intriguing Spitzer can read the fossil record of events that occurred billions of years ago within this beautiful and archetypal galaxy."

Spitzer captures a different view of the galaxy than visible-light telescopes. In visible views, the galaxy appears to be immersed in a glowing halo, which scientists had thought was relatively light and small.With Spitzer's infrared vision, a different view emerges. Spitzer sees old stars through the dust and reveals the halo has the right size and mass to be a giant elliptical galaxy.

While it is tempting to think the giant elliptical swallowed a spiral disk, astronomers say this is highly unlikely because that process would have destroyed the disk structure. Instead, one scenario they propose is that a giant elliptical galaxy was inundated with gas more than nine billion years ago.Early in the history of our universe, networks of gas clouds were common, and they sometimes fed growing galaxies, causing them to bulk up.

The gas would have been pulled into the galaxy by gravity, falling into orbit around the center and spinning out into a flat disk. Stars would have formed from the gas in the disk."This poses all sorts of questions," said Ruben Sanchez-Janssen from the European Southern Observatory, co-author of the study. "How did such a large disk take shape and survive inside such a massive elliptical? How unusual is such a formation process?"

Researchers say the answers could help them piece together how other galaxies evolve. Another galaxy, called Centaurus A, appears also to be an elliptical galaxy with a disk inside it. But its disk does not contain many stars.

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Study Finds Surprising Arctic Methane Emission Source

The fragile and rapidly changing Arctic region is home to large reservoirs of methane, a potent greenhouse gas. As Earth’s climate warms, the methane, frozen in reservoirs stored in Arctic tundra soils or marine sediments, is vulnerable to being released into the atmosphere, where it can add to global warming. Now a multi-institutional study by Eric Kort of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., has uncovered a surprising and potentially important new source of Arctic methane: the ocean itself.

Kort, a JPL postdoctoral scholar affiliated with the Keck Institute of Space Studies at the California Institute of Technology in Pasadena, led the analysis while he was a student at Harvard University, Cambridge, Mass. The study was conducted as part of the HIAPER Pole-to-Pole Observations (HIPPO) airborne campaign, which flew a specially instrumented National Science Foundation (NSF)/National Center for Atmospheric Research (NCAR) Gulfstream V aircraft over the Pacific Ocean from nearly pole to pole, collecting atmospheric measurements from Earth’s surface to an altitude of 8.7 miles (14 kilometers). The campaign, primarily funded by NSF with additional funding from NCAR, NASA and the National Oceanic and Atmospheric Administration, was designed to improve our understanding of where greenhouse gases are originating and being stored in the Earth system.

During five HIPPO flights over the Arctic from 2009 to 2010, Kort’s team observed increased methane levels while flying at low altitudes over the remote Arctic Ocean, north of the Chukchi and Beaufort Seas. The methane level was about one-half percent larger than normal background levels.

But where was the methane coming from? The team detected no carbon monoxide in the atmosphere that would point to possible contributions from human combustion activities. In addition, based on the time of year, location and nature of the emissions, it was extremely unlikely the methane was coming from high-latitude wetlands or geologic reservoirs.

By comparing locations of the enhanced methane levels with airborne measurements of carbon monoxide, water vapor and ozone, they pinpointed a source: the ocean surface, through cracks in Arctic sea ice and areas of partial sea ice cover. The cracks expose open Arctic seawater, allowing the ocean to interact with the air, and methane in the surface waters to escape into the atmosphere. The team detected no enhanced methane levels when flying over areas of solid ice.

Kort said previous studies by others had measured high concentrations of methane in Arctic surface waters, but before now no one had predicted that these enhanced levels of ocean methane would find their way to the overlying atmosphere.

So how is the methane being produced? The scientists aren’t yet sure, but Kort hinted biological production from living things in Arctic surface waters may be a likely culprit. “It’s possible that as large areas of sea ice melt and expose more ocean water, methane production may increase, leading to larger methane emissions,” he said. He said future studies will be needed to understand the enhanced methane levels and associated emission processes and to measure their total contribution to overall Arctic methane levels.

“While the methane levels we detected weren’t particularly large, the potential source region, the Arctic Ocean, is vast, so our finding could represent a noticeable new global source of methane,” he added. “As Arctic sea ice cover continues to decline in a warming climate, this source of methane may well increase. It’s important that we recognize the potential contribution from this source of methane to avoid falsely interpreting any changes observed in Arctic methane levels in the future.”

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A farewell to Star Trek's real life Shuttle Enterprise

It was six years after the final airing of the original Star Trek on television and the trekkie movement was alive and well. After a successful run in syndication, Paramount Pictures had announced and began script production on the franchise's first major film titled "Star Trek: The Motion Picture." The victory for show creator Gene Rodenberry and trek fans alike would be one of many in the Star Trek universe.

Fast forward less than a year to Rockwell International's facilities in Palmdale, California. Preparations to unveil to the public the first NASA Space Shuttle were underway. A formal dedication for Shuttle Constitution would be held on September 17th, 1976, on Constitution day.

Designated OV-101 (Orbiter Vehicle 101), Constitution was built to perform test flights within Earth's atmosphere. Designed without physical engines, a heat shield and many systems required for space flight, the space vehicle would never leave Earth, making it the only space shuttle never to fly in space.

While a full campaign of testing was fully underway, another campaign 3000 miles away would define Constitution forever. Momentum was building around a write-in campaign to request a name change of Shuttle Constitution. Without any official mention by The White House or President Ford's staff, over 400,000 Star Trek fans were petitioning the President to reconsider the name Constitution for America's first space shuttle. Their request was simple - call it Enterprise.

President Ford, during World War II, was stationed on the aircraft carrier Monterey, which coincidentally had served with the USS Enterprise. Stating that he was "partial to the name," he overrode the name Constitution and officially dubbed OV-101 Enterprise.

On Constitution Day, 1976, special guests along with NASA officials and President Ford dedicated the first in the fleet. Those special guests were from a not so distant television series. Joining NASA Administrator James Fletcher were Star Trek USS Enterprise crew members DeForest Kelley (Dr. "Bones" McCoy), George Takei (Mr. Sulu), James Doohan (Chief Engineer Montgomery "Scotty" Scott), Nichelle Nichols (Lt. Uhura), Leonard Nimoy (Mr. Spock), Gene Rodenberry (Series Creator), and Walter Koenig (Ensign Pavel Checkov).

Approach & Landing Tests

Less than five months after the formal dedication, Enterprise would take her maiden flight atop a Boeing 747 Shuttle Carrier Aircraft for a series of unmanned and unpowered tests to determine structural loads, handling, and monitoring of newly built ground systems. It was also an opportunity to test the ferry flight characteristics of the mated 747 and the shuttle itself. On August 12, 1977 Enterprise flew on its own for the first time with Commander Fred W. Haise, Jr. (former Apollo 13 Lunar Module Pilot) and Pilot C. Gordon Fullerton at the controls. The subsequent test flights would serve as the model for future shuttle landings after orbiting missions.

Retirement & Relocation

When all flight tests were completed, Enterprise was retired from duty. The vehicle had certain components removed which could be reused on on future shuttle missions. Enterprise then was sent on an international tour visiting the United Kingdom, France, Italy, Germany, Canada, and within the United States, California, Alabama and Louisiana. Enterprise was sent via barge to Louisiana for display during the 1984 World's Fair. While in California it was used as a fit-check to the never-used shuttle launch pad at Vandenberg Air Force Base.

On November 18, 1985 Enterprise was ferried to Washington, D.C., where it became property of the Smithsonian Institution and sat in storage until the opening of the James S. McDonnell Space Hangar at the Smithsonian's National Air & Space Museum's Udvar-Hazy Center in November of 2004.

On April 12, 2011, NASA officially announced the winning facilities that will permanently display the retired shuttle fleet. Enterprise, which was on display at the Udvar-Hazy center would be replaced by Shuttle Discovery and sent to the Intrepid Sea, Air & Space Museum in New York City.

Enterprise will depart Dulles International Airport and arrive at New York's John F. Kennedy International Airport on April 23rd, 2012 marking the first phase of relocation to the shuttle's new home. In June, Enterprise will move by barge to the Intrepid, going past such iconic landmarks including the Statue of Liberty and the World Trade Center.

"When the Enterprise touches down at JFK [Airport], it will signify the first step of its final journey to educate and inspire millions of people around the world about the groundbreaking work of the NASA space program," said U.S. Senator Charles E. Schumer (D – New York). "The Enterprise will immediately become an iconic and must-see destination in New York that will further contribute to our reputation as the greatest city in the world."

When the barge trip along the Hudson River is completed, Enterprise will be raised by crane to a place near the deck of the USS Intrepid, where it will be on public display in a temporary climate controlled facility until a permanent facility can be constructed.

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12-Mile-High Martian Dust Devil Caught in Act

A Martian dust devil roughly 12 miles high (20 kilometers) was captured whirling its way along the Amazonis Planitia region of Northern Mars on March 14. It was imaged by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Despite its height, the plume is little more than three-quarters of a football field wide (70 yards, or 70 meters).

Dust devils occur on Earth as well as on Mars. They are spinning columns of air, made visible by the dust they pull off the ground. Unlike a tornado, a dust devil typically forms on a clear day when the ground is heated by the sun, warming the air just above the ground. As heated air near the surface rises quickly through a small pocket of cooler air above it, the air may begin to rotate, if conditions are just right.

The image was taken during late northern spring, two weeks short of the northern summer solstice, a time when the ground in the northern mid-latitudes is being heated most strongly by the sun.

The Mars Reconnaissance Orbiter has been examining the Red Planet with six science instruments since 2006. Now in an extended mission, the orbiter continues to provide insights into the planet's ancient environments and how processes such as wind, meteorite impacts and seasonal frosts continue to affect the Martian surface today. This mission has returned more data about Mars than all other orbital and surface missions combined.

More than 21,700 images taken by HiRISE are available for viewing on the instrument team's website: http://hirise.lpl.arizona.edu . Each observation by this telescopic camera covers several square miles, or square kilometers, and can reveal features as small as a desk.

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project and the Mars Exploration Rover Project are managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena. Lockheed Martin Space Systems, Denver, built the orbiter. 

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Fermi Observations of Dwarf Galaxies Provide New Insights on Dark Matter

There's more to the cosmos than meets the eye. About 80 percent of the matter in the universe is invisible to telescopes, yet its gravitational influence is manifest in the orbital speeds of stars around galaxies and in the motions of clusters of galaxies. Yet, despite decades of effort, no one knows what this "dark matter" really is. Many scientists think it's likely that the mystery will be solved with the discovery of new kinds of subatomic particles, types necessarily different from those composing atoms of the ordinary matter all around us. The search to detect and identify these particles is underway in experiments both around the globe and above it.

Scientists working with data from NASA's Fermi Gamma-ray Space Telescope have looked for signals from some of these hypothetical particles by zeroing in on 10 small, faint galaxies that orbit our own. Although no signals have been detected, a novel analysis technique applied to two years of data from the observatory's Large Area Telescope (LAT) has essentially eliminated these particle candidates for the first time.

"In effect, the Fermi LAT analysis compresses the theoretical box where these particles can hide," said Jennifer Siegal-Gaskins, a physicist at the California Institute of Technology in Pasadena, Calif., and a member of the Fermi LAT Collaboration. Earlier today, she discussed the latest results of space-based dark matter searches in an invited talk at a meeting of the American Physical Society (APS) in Atlanta, Ga.

WIMPs, or Weakly Interacting Massive Particles, represent a favored class of dark matter candidates. Some WIMPs may mutually annihilate when pairs of them interact, a process expected to produce gamma rays -- the most energetic form of light -- that the LAT is designed to detect.

"One of the best places to look for these faint gamma-ray signals is in dwarf spheroidal galaxies, small satellites of our own Milky Way galaxy that we know possess large amounts of dark matter," Siegal-Gaskins explained. "From an astrophysical perspective, these are downright boring systems, with little gas or star formation and no objects like pulsars or supernova remnants that emit gamma rays."

In addition, many dwarfs lie far away from the plane of our galaxy, which produces a broad band of diffuse gamma-ray emission that stretches all around the sky. Selecting only dwarf galaxies at great distances from this plane helps minimize interference from the Milky Way.

The team examined two years of LAT-detected gamma rays with energies in the range from 200 million to 100 billion electron volts (GeV) from 10 of the roughly two dozen dwarf galaxies known to orbit the Milky Way. Instead of analyzing the results for each galaxy separately, the scientists developed a statistical technique -- they call it a "joint likelihood analysis" -- that evaluates all of the galaxies at once without merging the data together. No gamma-ray signal consistent with the annihilations expected from four different types of commonly considered WIMP particles was found.

For the first time, the results show that WIMP candidates within a specific range of masses and interaction rates cannot be dark matter. A paper detailing these results appeared in the Dec. 9, 2011, issue of Physical Review Letters.

"The fact that we look at 10 dwarf galaxies jointly not only increases the statistics, but it also makes the analysis much less sensitive to fluctuations in the gamma-ray background and to uncertainties in the way the dark matter may be distributed around the dwarfs," said Maja Llena Garde, a graduate student at Stockholm University in Sweden and a co-author of the study.

For any given properties of a dark matter particle, the distribution of the particles has a significant impact on the expected gamma-ray signal, a wrinkle that often is handled inadequately, if at all, in previous studies.

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