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Archive for May, 2013

Detection Of The Cosmic Gamma Ray Horizon Measures All The Light In The Universe Since The Big Bang


How much light has been emitted by all galaxies since the cosmos began? After all, almost every photon (particle of light) from ultraviolet to far infrared wavelengths ever radiated by all galaxies that ever existed throughout cosmic history is still speeding through the Universe today. If we could carefully measure the number and energy (wavelength) of all those photons—not only at the present time, but also back in time—we might learn important secrets about the nature and evolution of the Universe, including how similar or different ancient galaxies were compared to the galaxies we see today.

That bath of ancient and young photons suffusing the Universe today is called the extragalactic background light (EBL). An accurate measurement of the EBL is as fundamental to cosmology as measuring the heat radiation left over from the Big Bang (the cosmic microwave background) at radio wavelengths. A new paper, called “Detection of the Cosmic γ-Ray Horizon from Multiwavelength Observations of Blazars,” by Alberto Dominguez and six coauthors, just published today by the Astrophysical Journal—based on observations spanning wavelengths from radio waves to very energetic gamma rays, obtained from several NASA spacecraft and several ground-based telescopes—describes the best measurement yet of the evolution of the EBL over the past 5 billion years.

Full Story: http://hipacc.ucsc.edu/PressRelease/CGRH.html

Most Detailed Observations Ever Of The Ring Nebula


Image credit: NASA, ESA, and C. Robert O’Dell

Image credit: NASA, ESA, and C. Robert O’Dell

The NASA/ESA Hubble Space Telescope has produced the most detailed observations ever of the Ring Nebula (Messier 57). This image reveals intricate structure only hinted at in previous observations, and has allowed scientists to construct a model of the nebula in 3D — showing the true shape of this striking object.

Formed by a star throwing off its outer layers as it runs out of fuel, the Ring Nebula is an archetypal planetary nebula [1]. It is both relatively close to Earth and fairly bright, and so was first recorded in the late 18th century. As is common with astronomical objects, its precise distance is not known, but it is thought to lie just over 2000 light-years from Earth.

From Earth’s perspective, the nebula looks roughly elliptical. However, astronomers have combined ground-based data with new observations using the NASA/ESA Hubble Space Telescope to observe the nebula again, hunting for clues about its structure, evolution, physical conditions and motion.

It turns out that the nebula is shaped like a distorted doughnut. We are gazing almost directly down one of the poles of this structure, with a brightly coloured barrel of material stretching away from us.

Full Story and Images: http://www.spacetelescope.org/news/heic1310/
Also: http://hubblesite.org/newscenter/archive/releases/2013/13

Astronomers Team Up With The Public To Solve Decade Old Puzzle


An extremely precise measurement of the distance to a star system has finally allowed astronomers to solve a decade-old puzzle, confirming understanding of the way exotic objects like black holes interact with nearby stars.

Published today in prestigious journal Science, a team of astronomers headed by Dr James Miller-Jones from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), have measured the distance to star system SS Cygni to be 372 light years, much closer than a previous measurement made by the Hubble Space Telescope in the 1990s.

The measurement was made possible by amateur astronomers from the American Association of Variable Star Observers (AAVSO) who alerted the team to changes in the compact star system, triggering the team to start observations with two of the world’s most accurate radio telescopes.

If you hold your finger out at arm’s length and move your head from side to side, you should see your finger appear to wobble against the background. If you move your finger closer to your head, you’ll see it starts to wobble more. We did the exact same thing with SS Cygni – we measured how far it moved against some very distant galaxies as the Earth moved around the Sun,” Dr James Miller-Jones said.

Full Story: http://www.icrar.org/home/astronomers-team-up-with-the-public-to-solve-decade-old-puzzle
Also: http://www.nrao.edu/pr/2013/sscyg/
Also: http://news.ualberta.ca/newsarticles/2013/may/ualberta-teams-with-citizen-scientists-to-solve-space-mystery

Black Hole Powered Jets Plow Into Galaxy

May 22, 2013 1 comment

X-ray: NASA / CXC/SAO / A.Siemiginowska et al; Optical: NASA / STScI; Radio: NSF / NRAO / VLA

X-ray: NASA / CXC/SAO / A.Siemiginowska et al; Optical: NASA / STScI; Radio: NSF / NRAO / VLA

This composite image of a galaxy illustrates how the intense gravity of a supermassive black hole can be tapped to generate immense power. The image contains X-ray data from NASA’s Chandra X-ray Observatory (blue), optical light obtained with the Hubble Space Telescope (gold) and radio waves from the NSF’s Very Large Array (pink).

This multi-wavelength view shows 4C+29.30, a galaxy located some 850 million light years from Earth. The radio emission comes from two jets of particles that are speeding at millions of miles per hour away from a supermassive black hole at the center of the galaxy. The estimated mass of the black hole is about 100 million times the mass of our Sun. The ends of the jets show larger areas of radio emission located outside the galaxy.

Full Story and Images: http://www.chandra.harvard.edu/photo/2013/4c2930/

Orion’s Hidden Fiery Ribbon


Credit: ESO/Digitized Sky Survey 2

Credit: ESO/Digitized Sky Survey 2

Clouds of gas and interstellar dust are the raw materials from which stars are made. But these tiny dust grains block our view of what lies within and behind the clouds — at least at visible wavelengths — making it difficult to observe the processes of star formation.

This is why astronomers need to use instruments that are able to see at other wavelengths of light. At submillimetre wavelengths, rather than blocking light, the dust grains shine due to their temperatures of a few tens of degrees above absolute zero. The APEX telescope with its submillimetre-wavelength camera LABOCA, located at an altitude of 5000 metres above sea level on the Chajnantor Plateau in the Chilean Andes, is the ideal tool for this kind of observation.

This spectacular new picture shows just a part of a bigger complex called the Orion Molecular Cloud, in the constellation of Orion (The Hunter). A rich melting pot of bright nebulae, hot young stars and cold dust clouds, this region is hundreds of light-years across and located about 1350 light-years from us. The submillimetre-wavelength glow arising from the cold dust clouds is seen in orange in this image and is overlaid on a view of the region taken in the more familiar visible light.

The dust clouds form beautiful filaments, sheets, and bubbles as a result of processes including gravitational collapse and the effects of stellar winds. These winds are streams of gas ejected from the atmospheres of stars, which are powerful enough to shape the surrounding clouds into the convoluted forms seen here.

Full Story and Images: http://www.eso.org/public/news/eso1321/

Storms On Uranus, Neptune Confined To Upper Atmosphere


The Voyager 2 spacecraft photographed bands of clouds around Neptune during its flyby in 1989. Photo: NASA

The Voyager 2 spacecraft photographed bands of clouds around Neptune during its flyby in 1989. Photo: NASA

Similar to the giant gas planets Jupiter and Saturn, their smaller cousins, Uranus and Neptune, have long been known to harbor swirling clouds and violent winds churning up their atmospheres. Massive bands of jet streams encircling the entire planet have been observed in both cases. But given that Uranus’ atmosphere is believed to be thick enough to swallow the entire Earth, it was not known just how far the weather perturbations reach into the planet’s interior.

Now a team of planetary scientists with the University of Arizona’s Lunar and Planetary Laboratory, including William Hubbard and Adam Showman, has published the results of new analyses that put an upper limit to the weather zone on Uranus and Neptune. According to their data, reported in the journal Nature, the atmosphere on both planets goes from screaming winds of infernal violence to dead-quiet at a much shallower depth than previously thought.

“Our analyses show that the dynamics are confined to a thin weather layer no more than about 680 miles deep,” said Hubbard. “This number is an upper limit, so in reality, it is possible that the atmosphere quiets down even shallower than that.”

Full Story: http://www.uanews.org/story/storms-on-uranus-neptune-confined-to-upper-atmosphere

Mars Rover Opportunity Examines Clay Clues In Rock


Image Credit: NASA/JPL-Caltech / Cornell / Arizona State Univ.

Image Credit: NASA/JPL-Caltech / Cornell / Arizona State Univ.

NASA’s senior Mars rover, Opportunity, is driving to a new study area after a dramatic finish to 20 months on “Cape York” with examination of a rock intensely altered by water.

The fractured rock, called “Esperance,” provides evidence about a wet ancient environment possibly favorable for life. The mission’s principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., said, “Esperance was so important, we committed several weeks to getting this one measurement of it, even though we knew the clock was ticking.”

The mission’s engineers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., had set this week as a deadline for starting a drive toward “Solander Point,” where the team plans to keep Opportunity working during its next Martian winter.

“What’s so special about Esperance is that there was enough water not only for reactions that produced clay minerals, but also enough to flush out ions set loose by those reactions, so that Opportunity can clearly see the alteration,” said Scott McLennan of the State University of New York, Stony Brook, a long-term planner for Opportunity’s science team.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-167