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Astronews

Hubble's deepest view of Universe unveils never-before-seen galaxies

The new Wide Field Camera 3 aboard the NASA/ESA Hubble Space Telescope has taken the deepest image yet of the Universe in near-infrared light. The faintest and reddest objects in the image are likely the oldest galaxies ever identified, having formed between only 600–900 million years after the Big Bang.

Hubble old galaxies
Read the whole article at Spacetelescope.org

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Time for a new theory of gravitation? Galaxies challenge Newtonian model

The high speed of stars and apparent presence of ‘dark matter’ in the satellite galaxies that orbit our Milky Way Galaxy presents a direct challenge to Newton’s theory of gravitation, according to physicists from Germany, Austria and Australia. Professor Pavel Kroupa of the University of Bonn’s Argelander-Institut fuer Astronomie (AlfA) will discuss the results of the team’s two studies in a presentation on Wednesday 22nd April at the European Week of Astronomy and Space Science conference at the University of Hertfordshire.

The team of scientists looked at the distribution of satellite dwarf galaxies and discovered they were not where they should be. “There is something odd about their distribution”, explains Professor Kroupa. “They should be uniformly arranged around the Milky Way, but this is not what we found.” The astronomers discovered that the eleven brightest of the dwarf galaxies lie more or less in the same plane - in a kind of disk shape - and that they revolve in the same direction around the Milky Way (in the same way as planets in the Solar System revolve around the Sun).

Professor Kroupa and the other physicists believe that this can only be explained if today’s satellite galaxies were created by ancient collisions between young galaxies. Team member and former colleague Dr Manuel Metz, now at the Deutsches Zentrum fuer Luft- and Raumfahrt, also worked on the study. “Fragments from early collisions can form the revolving dwarf galaxies we see today” comments Dr Metz. But he adds that this introduces a paradox. “Calculations suggest that the dwarf satellites cannot contain any dark matter if they were created in this way. But this directly contradicts other evidence. Unless the dark matter is present, the stars in the galaxies are moving around much faster than predicted by Newton’s standard theory of gravitation.”

Read the whole article at Royal Astronomical Society

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NASA's Kepler Captures First Views of Planet-Hunting Territory

PASADENA, Calif. -- NASA's Kepler mission has taken its first images of the star-rich sky where it will soon begin hunting for planets like Earth.

The new "first light" images show the mission's target patch of sky, a vast starry field in the Cygnus-Lyra region of our Milky Way galaxy. One image shows millions of stars in Kepler's full field of view, while two others zoom in on portions of the larger region. The images can be seen online at:

http://www.nasa.gov/mission_pages/kepler/multimedia/20090416.html

Read the whole article at NASA website

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WMAP Reveals Neutrinos, End of Dark Ages, First Second of Universe

WMAP NASA released this week five years of data collected by the Wilkinson Microwave Anisotropy Probe (WMAP) that refines our understanding of the universe and its development. It is a treasure trove of information, including at least three major findings:

- New evidence that a sea of cosmic neutrinos permeates the universe

- Clear evidence the first stars took more than a half-billion years to create a cosmic fog

- Tight new constraints on the burst of expansion in the universe's first trillionth of a second

"We are living in an extraordinary time," said Gary Hinshaw of NASA's Goddard Space Flight Center in Greenbelt, Md. "Ours is the first generation in human history to make such detailed and far-reaching measurements of our universe."

WMAP measures a remnant of the early universe - its oldest light. The conditions of the early times are imprinted on this light. It is the result of what happened earlier, and a backlight for the later development of the universe. This light lost energy as the universe expanded over 13.7 billion years, so WMAP now sees the light as microwaves. By making accurate measurements of microwave patterns, WMAP has answered many longstanding questions about the universe's age, composition and development.

Read the whole article at nasa.gov

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Pioneer 10/11 anomaly

Something strange is happening in the outer reaches of our solar system. The Pioneer 10 and 11 spacecraft are not where they are supposed to be. These missions, launched in 1972 and 1973, have covered hundreds of millions of kilometers, heading toward the edge of our solar system. But something is holding them back. Each year, they fall behind in their projected travel by about 5,000 kilometers (3,000 miles). Jet Propulsion Laboratory scientist John Anderson and his colleagues have been searching for an explanation since 1980. But as of yet, they have found nothing conclusive; no spacecraft behavior or previously unknown property of the outer solar system can explain the deceleration of the Pioneer spacecraft. Scientists are being forced to consider the unthinkable: something may be wrong with our understanding of the laws of physics. An important line of inquiry will be to study mounds of Doppler (velocity) data and spacecraft status data (like temperatures) that have been unavailable to researchers—but that is about to change. Read more ...