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Milky Way a swifter spinner and more massive

...New suggest that our home Galaxy is spinning a dizzy 100,000 miles per hour faster than previously believed...

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Fermi unveils a dozen new pulsars

...NASA's Fermi Gamma-ray Space Telescope has discovered 12 new gamma-ray-only pulsars and has detected gamma-ray pulses from 18 others...

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Active galaxies vary across the Universe

...NASA’s Swift spacecraft is revealing that nearby active galaxies are more alive than those located halfway across the Universe...

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STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.

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STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.

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STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

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 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.

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Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

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Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

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Tuning in to the cosmic radio

BY DR EMILY BALDWIN

ASTRONOMY NOW

Posted: 09 January, 2009

According to scientists presenting their work at the American Astronomical Society meeting this week, cosmic radio noise booms six times louder than expected, potentially drowning out the sounds of the early Universe.

Scientists made the discovery using the ballon-borne ARCADE instrument, or Absolute Radiometer for Cosmology, Astrophysics and Diffuse Emission, which has resided at an altitude of 36 kilometres – the boundary between the Earth’s atmosphere and the vacuum of space – since July 2006. The aim of the mission was to search the sky for heat from the first generation of stars, but instead, it uncovered an interesting phenomenon.

ARCADE viewed about 7 percent of the sky, represented by the coloured region on this all-sky radio map. The plane of the Milky Way, runs across the centre. Image: NASA/ ARCADE.

"The Universe really threw us a curve," says team leader Alan Kogut of NASA’s Goddard Space Flight Center. "Instead of the faint signal we hoped to find, here was this booming noise six times louder than anyone had predicted."

Many objects in the Universe emit radio waves, including gas in the outermost halo of our own Milky Way Galaxy and primordial stars, but the source of this cosmic radio background is baffling scientists. Team member Dale Fixsen of the University of Maryland says that there just aren’t enough radio galaxies to account for the signal ARCADE detected. "You'd have to pack them into the Universe like sardines," he says. "There wouldn't be any space left between one galaxy and the next."

While the problem of this radio excess is an exciting discovery in itself, it comes with some serious implications. The pirate radio static that is controlling the cosmic airwaves could be drowning out the much sought after signal of the earliest stars of the Universe, thought to have formed shortly after the Big Bang 13.7 billion years ago. It’s not all bad news, however, for the static could provide important clues to the development of galaxies and radio sources in the Universe’s infancy.

"This is what makes science so exciting," says Michael Seiffert of NASA's Jet Propulsion Laboratory. "You start out on a path to measure something, in this case, the heat from the very first stars, but run into something else entirely, something unexplained."

ARCADE discovered a screen of extra-loud cosmic static (represented by the white band at the top of this illustration) that is blocking the heat from the first stars. Image: NASA/ARCADE/Roen Kelly.

ARCADE is the first instrument to measure the radio sky with enough precision to detect this curious signal. It operates at the same temperature as the cosmic microwave background radiation, the remnant heat of the Big Bang, just 2.7 degrees above absolute zero. "If ARCADE is the same temperature as the microwave background, then the instrument's heat cannot contaminate the cosmic signal," explains Kogut.

Four papers describing various aspects of ARCADE’s discovery have been submitted to The Astrophysical Journal.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
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Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
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3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
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