Archive

Archive for March, 2014

Dramatic New Portrait Helps Define Milky Way’s Shape, Contents


Credit: NASA/JPL-Caltech/University of Wisconsin-Madison

Credit: NASA/JPL-Caltech/University of Wisconsin-Madison

Using more than 2 million images collected by NASA’s orbiting Spitzer Space Telescope, a team of Wisconsin scientists has stitched together a dramatic 360-degree portrait of the Milky Way, providing new details of our galaxy’s structure and contents.

The new composite picture, using infrared images gathered over the last decade, was unveiled today at a TED conference in Vancouver. The galactic portrait provides an unprecedented look at the plane of our galaxy, using the infrared imagers aboard Spitzer to cut through the interstellar dust that obscures the view in visible light.

“For the first time, we can actually measure the large-scale structure of the galaxy using stars rather than gas,” explains Edward Churchwell, a University of Wisconsin-Madison professor of astronomy whose group compiled the new picture, which looks at a thin slice of the galactic plane. “We’ve established beyond the shadow of a doubt that our galaxy has a large bar structure that extends halfway out to the sun’s orbit. We know more about where the Milky Way’s spiral arms are.”

Link To Full Story

DEM L241: Hardy Star Survives Supernova Blast


Credit: X-ray: NASA/CXC/SAO/F.Seward et al; Optical: NOAO/CTIO/MCELS, DSS

Credit: X-ray: NASA/CXC/SAO/F.Seward et al; Optical: NOAO/CTIO/MCELS, DSS

When a massive star runs out fuel, it collapses and explodes as a supernova. Although these explosions are extremely powerful, it is possible for a companion star to endure the blast. A team of astronomers using NASA’s Chandra X-ray Observatory and other telescopes has found evidence for one of these survivors.

This hardy star is in a stellar explosion’s debris field – also called its supernova remnant – located in an HII region called DEM L241. An HII (pronounced “H-two”) region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms (HI) to form clouds of ionized hydrogen (HII). This HII region is located in the Large Magellanic Cloud, a small companion galaxy to the Milky Way.

A new composite image of DEM L241 contains Chandra data (purple) that outlines the supernova remnant. The remnant remains hot and therefore X-ray bright for thousands of years after the original explosion occurred. Also included in this image are optical data from the Magellanic Cloud Emission Line Survey (MCELS) taken from ground-based telescopes in Chile (yellow and cyan), which trace the HII emission produced by DEM L241. Additional optical data from the Digitized Sky Survey (white) are also included, showing stars in the field.

Link To Full Story

NASA Releases First Interactive Mosaic Of Lunar North Pole


Image Credit: NASA/GSFC/Arizona State University

Image Credit: NASA/GSFC/Arizona State University

Scientists, using cameras aboard NASA’s Lunar Reconnaissance Orbiter (LRO), have created the largest high resolution mosaic of our moon’s north polar region. The six-and-a-half feet (two-meters)-per-pixel images cover an area equal to more than one-quarter of the United States.

Web viewers can zoom in and out, and pan around an area. Constructed from 10,581 pictures, the mosaic provides enough detail to see textures and subtle shading of the lunar terrain. Consistent lighting throughout the images makes it easy to compare different regions.

“This unique image is a tremendous resource for scientists and the public alike,” said John Keller, LRO project scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. “It’s the latest example of the exciting insights and data products LRO has been providing for nearly five years.”

“Creation of this giant mosaic took four years and a huge team effort across the LRO project,” said Mark Robinson, principal investigator for the LROC at Arizona State University in Tempe. “We now have a nearly uniform map to unravel key science questions and find the best landing spots for future exploration.”

Link To Full Story And Other Links

NASA STEREO Observes One Of The Fastest CMEs On Record


Credit: NASA/STEREO

Credit: NASA/STEREO

On July 23, 2012, a massive cloud of solar material erupted off the sun’s right side, zooming out into space, passing one of NASA’s Solar TErrestrial RElations Observatory (STEREO) spacecraft along the way. Using the STEREO data, scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md. clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling between 1,800 and 2,200 miles per second as it left the sun.

Conversations began to buzz and the emails to fly: this was the fastest CME ever observed by STEREO, which since its launch in 2006 has helped make CME speed measurements much more precise. Such an unusually strong bout of space weather gives scientists an opportunity to observe how these events affect the space around the sun, as well as to improve their understanding of what causes them.

“Between 1,800 and 2,200 miles per second puts it without question as one of the top five CMEs ever measured by any spacecraft,” says solar scientist Alex Young at Goddard. “And if it’s at the top of that velocity range it’s probably the fastest.”

Link To Full Story And Videos

Hubble Revisits The Monkey Head Nebula For 24th Birthday Snap


Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

To celebrate its 24th year in orbit, the NASA/ESA Hubble Space Telescope has released a beautiful new image of part of NGC 2174, also known as the Monkey Head Nebula. This colourful region is filled with young stars embedded within bright wisps of cosmic gas and dust.

NGC 2174 lies about 6400 light-years away in the constellation of Orion (The Hunter). Hubble previously viewed this part of the sky back in 2001, creating a stunning image released in 2011, and the space telescope has now revisited the region to celebrate its 24th year of operation.

Nebulae are a favourite target for Hubble. Their colourful plumes of gas and fiery bright stars create ethereally beautiful pictures. Some of the most famous of Hubble’s images have been of nebulae — for example, the telescope’s 22nd and 23rd anniversary images of the Tarantula and Horsehead nebulae, and its festive 2012 image of planetary nebula NGC 5189.

The detail shown in this image lies within NGC 2174, a nebula which gets its more common name, the Monkey Head Nebula, from its curiously familiar shape when viewed in wide-field images.

Link To Full Story
Link To Another Story

First Direct Evidence Of Inflation And Primordial Gravitational Waves


Credit: The BICEP2 Collaboration

Credit: The BICEP2 Collaboration

Astronomers announced today that they have acquired the first direct evidence that gravitational waves rippled through our infant universe during an explosive period of growth called inflation. This is the strongest confirmation yet of cosmic inflation theories, which say the universe expanded by 100 trillion trillion times in less than the blink of an eye.

“The implications for this detection stagger the mind,” says Jamie Bock, professor of physics at Caltech, laboratory senior research scientist at the Jet Propulsion Laboratory (JPL) and project co-leader. “We are measuring a signal that comes from the dawn of time.”

Our universe burst into existence in an event known as the Big Bang 13.8 billion years ago. Fractions of a second later, space itself ripped apart, expanding exponentially in an episode known as inflation. Telltale signs of this early chapter in our universe’s history are imprinted in the skies in a relic glow called the cosmic microwave background. Tiny fluctuations in this afterglow provide clues to conditions in the early universe.

Small, quantum fluctuations were amplified to enormous sizes by the inflationary expansion of the universe. This process created density waves that make small differences in temperature across the sky where the universe was denser, eventually condensing into galaxies and clusters of galaxies. But as theorized, inflation should also produce gravitational waves, ripples in space-time propagating throughout the universe. Observations from the BICEP2 telescope at the South Pole now demonstrate that gravitational waves were created in abundance during the early inflation of the universe.

Link To Full Story
Link To Another Story
Link To Another Story And Video

The Dusty Heart Of An Active Galaxy


Credit: NASA HST, News Release STScI-2000-37

Credit: NASA HST, News Release STScI-2000-37

An international research team led by Konrad Tristram from the Max-Planck-Institute for Radio Astronomy in Bonn, Germany, obtained the most detailed view so far of the warm dust in the environment of a supermassive black hole in an active galaxy. The observations of the Circinus galaxy show, for the first time, that the dust directly illuminated by the central engine of the active galaxy is located in two distinct components: an inner warped disk and a surrounding larger distribution of dust. Most likely, the larger component is responsible for most of the obscuration of the inner regions close to the supermassive black hole. Such a configuration is significantly more complex than the simple dusty doughnut, which has been favoured for the last few decades.

In active galactic nuclei, enormous amounts of energy are released due to the feeding of the supermassive black hole in the centre of the galaxy. Such black holes have masses of a million or billion times the mass of the sun. The matter spiralling in onto the black hole becomes so hot and luminous that it outshines its entire galaxy with billions of stars. The huge amounts of energy released also affect the surrounding galaxy. Active galactic nuclei are therefore thought to play an important role in the formation and evolution of galaxies and hence in the formation of the universe as presently seen.

Link To Full Story