ESA Planck Telescope: Sky Survey changes date on early stars

Planck has mapped the delicate polarisation of the CMB across the entire sky

Scientists working on ESA's Planck satellite say the first stars in the Universe lit up later than was previously thought.

The team has made the most precise map of the "oldest light" in the cosmos.

Earlier observations of this radiation had suggested that the first generation of stars burst into life about 420 million years after the Big Bang.

The new Planck data now indicates they fired up around 560 million years after the Universe got going.

"This difference of 140 million years might not seem that significant in the context of the 13.8-billion-year history of the cosmos, but proportionately it's actually a very big change in our understanding of how certain key events progressed at the earliest epochs," said Prof George Efstathiou, one of the leaders of the Planck Science Collaboration.

Subtle signal
The assessment is based on studies of the "afterglow" of the Big Bang, the ancient light called the Cosmic Microwave Background (CMB), which still washes over the Earth today.

The European Space Agency's (ESA) Planck satellite mapped this "fossil" between 2009 and 2013.

It contains a wealth of information about early conditions in the Universe, and can even be used to work out its age, shape and do an inventory of its contents.

Scientists can also probe it for very subtle "distortions" that tell them about any interactions the CMB has had on its way to us.

Forging elements
One of these would have been imprinted when the infant cosmos underwent a major environmental change known as re-ionisation.

It is when the cooling neutral hydrogen gas that dominated the Universe in the aftermath of the Big Bang was then re-energised by the ignition of the first stars.

These hot giants would have burnt brilliant but brief lives, producing the very first heavy elements. But they would also have "fried" the neutral gas around them - ripping electrons off the hydrogen protons.

And it is the passage of the CMB through this maze of electrons and protons that would have resulted in it picking up a subtle polarisation.

Impression: The first stars would have been unwieldy behemoths that burnt brief but brilliant lives

The Planck team has now analysed this polarisation in fine detail and determined it to have been generated at 560 million years after the Big Bang.

The American satellite WMAP, which operated in the 2000s, made the previous best estimate for re-ionisation at 420 million years.

The problem with that number was that it sat at odds with Hubble Space Telescope observations of the early Universe.

Hubble could not find stars and galaxies in sufficient numbers to deliver the scale of environmental change at the time when WMAP suggested it was occurring.

Planck's new timing "effectively solves the conflict," commented Prof Richard McMahon from Cambridge University, UK.

"We had two groups of astronomers who were basically working on different sides of the problem. The Planck people came at it from the Big Bang side, while those of us who work on galaxies came at it from the 'now side'.

"It's like a bridge being built over a river. The two sides do now join where previously we had a gap," he told reporters.

That gap had prompted scientists to invoke complicated scenarios for how re-ionisation could have occurred, including the ideas that there were an even earlier population of giant stars or energetic black holes. Such solutions are no longer needed.

The finding is also good news for the next generation of observatories like the James Webb Space Telescope, which will have the power to see right through the epoch of re-ionisation.

Sky Survey Map of Massive Galaxies, Distant Black Holes, Clues to Dark Matter and Energy

The Sloan Digital Sky Survey III(SDSS-III) has released the largest-ever three-dimensional map of massive galaxies and distant black holes, helping astronomers better explain the mysterious “dark matter” and “dark energy” that make up 96 percent of the universe. 

According to SDSS-III scientific spokesperson and University of Pittsburgh assistant professor of physics and astronomy Michael Wood-Vasey, scientists using the map, titled Data Release 9 (DR9), can retrace the Universe’s history over the last seven billion years. 

Wood-Vasey co-wrote the DR9 summary paper featured on the arXiv database.

“This is science at its collaborative best,” said Wood-Vasey. “SDSS-III scientists work together to address big questions extending from our own galaxy to distant reaches of the Universe, and then they share that data with the world to allow anyone to make the next big discovery.”

The new DR9 map of the Universe includes images of 200 million galaxies and spectra measurements of how much light galaxies gives off at different wavelengths— of 1.35 million galaxies, including new spectra of 540,000 galaxies dating from when the universe was half its present age.

Researchers at SDSS-III say that studying spectra is important because it allows scientists to figure out how much the Universe has expanded since the light left each galaxy.

Additionally, having this new data to analyze not only helps researchers understand the distant Universe, and the Earth’s own Milky Way Galaxy.

DR9 includes better estimates regarding the temperatures and chemical compositions of more than a half million stars in the Milky Way.

DR9 represents the latest in a series of data releases stretching back to 2001. This release includes new data from the ongoing SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), which will eventually measure the positions of 1.5 million massive galaxies over the past seven billion years of cosmic time, as well as 160,000 quasars—giant black holes feeding on stars and gas—from as long ago as 12 billion years.

While all of these new images and spectra contain the promise of new discoveries about the universe, SDSS-III is only in the middle of its six-year survey and will release three times as much data by the time it has completed its work, in 2014.

All the newly released data is now available on the DR9 Web site, at http://www.sdss3.org/dr9.

Additionally, the SkyServer Web site includes lesson plans for teachers who use DR9 data to teach astronomy and other topics in science, technology, and mathematics.

NASA Provides New Funding to Asteroid Search Program

The asteroid 2012 DA14 currently has the greatest chance of impacting Earth, possibly crashing down on Feb. 16, 2020. NASA

The search for potentially dangerous asteroids will continue through 2015 after federal funders agreed to give the NASA-funded Catalina Sky Survey, a $4.1 million funding boost, researchers announced.

The survey uses two telescopes run by the University of Arizona to scan the sky for objects that enter a collision course with Earth.

The new funds will be used to upgrade the program's telescopes, something researchers said is sorely needed.

"When we began observing in 2000, our image sensor was 16 megapixels, which was large by any standard," Steve Larson, a Catalina Sky Survey researcher and senior staff scientist at University of Arizona, said in a statement.

"Today, commonly available consumer digital cameras have surpassed that size, and we were reaching the limit of productivity with our current camera design."

The new telescopes will quadruple the amount of sky the telescopes cover each month.

The asteroid watchers also plan to use the new money to develop more sensitive software and conduct more searches.

The Catalina Sky Survey uses two telescopes to take images of a selected part of the sky roughly 10 minutes apart, according to a press release.

A computer program then scrutinizes the images to identify objects moving in a straight line.

If the object qualifies as a near-Earth object (NEO), an object whose trajectory will bring it close to Earth, the survey reports it to the Smithsonian Institution in Washington, D.C.

The survey discovered 586 near-Earth asteroids in 2011, 65 percent of all NEOs discovered.

"NASA has recognized that over the last seven years, our program has constantly strived to improve its performance, and has collaborated with others to find new ways to exploit the nearly 1,000 images we take every night with our two telescopes in the mountains north of Tucson," Edward Beshore, principal investigator of the Catalina Sky Survey, said in a statement. "I think NASA recognizes the CSS as a valuable service to, well, humanity."

Congress mandated the Spaceguard Survey, which the Catalina Sky Survey is a part of, in 1998.

The Spaceguard Survey required 90 percent of NEO's over 1 km in diameter to be found by 2008.

As of 2011, researchers found 911 NEO's through the Spaceguard program and expect 70 more objects will be found, according to NASA.

NASA tracks every NEO that has a chance of colliding with Earth in the next 100 years.

UK BBC Stargazing Guide - PDF

Click on the picture to see the full 14 page guide

NASA Sky Survey - Cygnus X-1: A Stellar Mass Black Hole

On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box.

Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across.

An artist's illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star.

The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets.

A trio of papers with data from radio, optical and X-ray telescopes, including NASA's Chandra X-ray Observatory, has revealed new details about the birth of this famous black hole that took place millions of years ago.

Using X-ray data from Chandra, the Rossi X-ray Timing Explorer, and the Advanced Satellite for Cosmology and Astrophysics, scientists were able to determine the spin of Cygnus X-1 with unprecedented accuracy, showing that the black hole is spinning at very close to its maximum rate.

Its event horizon -- the point of no return for material falling towards a black hole -- is spinning around more than 800 times a second.

Using optical observations of the companion star and its motion around its unseen companion, the team also made the most precise determination ever for the mass of Cygnus X-1, of 14.8 times the mass of the Sun.

It was likely to have been almost this massive at birth, because of lack of time for it to grow appreciably.

The researchers also announced that they have made the most accurate distance estimate yet of Cygnus X-1 using the National Radio Observatory's Very Long Baseline Array (VLBA).

The new distance is about 6,070 light years from Earth. This accurate distance was a crucial ingredient for making the precise mass and spin determinations.

Credits: X-ray: NASA/CXC; Optical: Digitized Sky Survey

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Skywatcher: Stunning Image of Aurora Borealis

Skywatcher Kwon, O Chul of The World At Night (TWAN), shot this image of the Northern Lights at Yellowknife in northern Canada.

CREDIT: (c)Kwon O Chul / TWAN

It took a collision of charged particles from Earth’s magnetosphere and one veteran landscape astrophotographer from Seoul, Korea to deliver this green spectacle.

Skywatcher Kwon, O Chul of The World At Night (TWAN), traveled to Yellowknife in northern Canada with a Canon 5d mark II + 24mm lens to capture this image of the Northern Lights.

The northern and southern lights — also known as the aurora — are mostly witnessed in polar latitudes. A clash of charged particles from Earth's magnetosphere with atoms and molecules of Earth's atmosphere (at altitudes above 50 miles, or 80 km) cause these lights. Solar wind from the sun carries these particles to Earth.

Kwon often uses several medium-format and panorama-format film cameras in his exhibitions. The skywatcher “looks for the harmony between celestial motion and star trails, ancient relics, and Korean beautiful landscapes,” according to the TWAN website. 

The entire night sky

In this photograph provided by Nick Risinger of Skysurvey.org, the entire night sky is shown in a composite photograph made from more than 37,000 exposures taken in different locations all over the world.

Risinger traveled more than 60,000 miles by air and land and spent more than a year to produce the photo.

Picture: AP Photo/Skysurvey.org, Nick Risinger

24HR view of the Sky

Photographer Chris Kotsiopoulos; Chris’ Website
Summary Author: Chris Kotsiopoulos
 
After wondering for some time whether it was possible to image the sky from one morning to the next where he lives in Athens Greece, Chris decided to give it a try.

After hours of planning and preparation, and a full day of shooting, the image above is the result of this labour of love.

It took about 12 hours to pull together and process a single image that included over 500 star trails, 35 shots of the Sun and 25 landscape pictures.

The plan was to make the image on the day of the solstice (December 21) when the Sun’s stay in the sky was short (in the Northern Hemisphere) and the star trail durations were long.

Of course, trying to find clear weather for a given 24-hour period is not an easy chore. However, he was very patient, and the weather eventually cooperated (on December 30-31, 2010).

He had to stay at the same place for approximately 30 hours. In addition, he was on location 2-3 hours before sunrise to make the preparations and conduct some test shooting.

He also needed to stay an extra 2-3 hours the second day to shoot part of the Sun's sequence, which was lost the first morning due to clouds.

Chris chose Sounion (Temple of Poseidon) as the setting for this project. Click on image to see labels.

Oxygen in White Dwarfs - Near Miss to Supernova

Oxygen on a planet might be a sign of life, but in two peculiar white dwarf stars it could indicate a narrow escape from a violent death. Their oxygen content marks them as failed stellar bombs – the remnants of stars that almost went supernova.

The new stars are among thousands of white dwarfs picked up by the Sloane Digital Sky Survey. Like all white dwarfs they are the dead, cooling cores left behind by mainstream stars, and are mainly made of helium. Usually the second most plentiful ingredient is carbon – but when a group of astronomers led by Boris Gänsicke at the University of Warwick, UK, analysed the spectrum of light from these two white dwarfs, they found that the objects hold far more oxygen than carbon.

"It's extreme – these things look very different from any white dwarfs we've seen before," says team member Danny Steeghs.

Creating so much oxygen requires a nuclear furnace fiercer than that needed for a carbon-rich mixture, so the stars that spawned these white dwarfs must have been hot and massive. Simulations suggest that they must have been almost too big to end their days gently – any larger, and they would have grown a core so massive and dense that it would inevitably have collapsed, releasing enough energy to blow the rest of the star apart in a supernova explosion.