NASA launches telescope in search of gamma rays

NASA launched a telescope Wednesday to scout out elusive, super high-energy gamma rays lurking in the universe. Glast — a NASA acronym standing for Gamma-ray Large Area Space Telescope — began its five- to 10-year Earth-orbiting mission with a midday blastoff aboard a Delta rocket. The $690 million telescope, supported by six countries, will pick up where NASA’s Compton Gamma Ray Observatory left off before its deliberate destruction in 2000, but in a bigger and better way. In addition to the United States, participating countries include Italy, France, Germany, Sweden and Japan. With superior new technology and insight gained from Compton and other telescopes, Glast will be able to do in three hours, or two orbits of Earth — survey the entire sky — what Compton took 15 months to do. What’s more, Glast and its particle detectors are much more sensitive and precise, and should provide an unprecedented view into the high-energy universe from a 345-mile(555-kilometer)-high orbit.

Site – http://www.cnn.com

Milky Way loses two (major) arms

For decades, astronomers have pictured our galaxy as sporting four major, spiral arms, however new images effectively sever two appendages, revealing the Milky Way has just two major arms.

“We’re not proposing that they change the positions of the arms,” said Robert Benjamin of the University of Wisconsin, Whitewater. “What we’re proposing is a change in the emphasis of the arms.” Benjamin will present his team’s results today here at a meeting of the American Astronomical Society (AAS).

The findings confirm an earlier observation by a team of astronomers, making a strong case that the Milky Way has two major spiral arms, a common structure for galaxies with bars. These major arms have the greatest densities of both young, bright stars and older, so-called red-giant stars.

Site – http://www.usatoday.com

Doughnut (Torus)-shaped Universe bites back

Reminiscent of how humans used to think the earth was a myriad of shapes and sizes before discovering that it was actually a sphere about 12,742 km in diameter, we are now beginning to have revelations about our universe which may give it a distinct shape and size.

The idea that the universe is finite and relatively small, rather than infinitely large, first became popular in 2003, when cosmologists noticed unexpected patterns in the cosmic microwave background (CMB) – the relic radiation left behind by the Big Bang.The CMB is made up of hot and cold spots that represent ripples in the density of the infant Universe, like waves in the sea. An infinite Universe should contain waves of all sizes, but cosmologists were surprised to find that longer wavelengths were missing from measurements of the CMB made by NASA’s Wilkinson Microwave Anisotropy Probe.

One explanation for the missing waves was that the universe is finite. “You can think of the Universe as a musical instrument – it cannot sustain vibrations that have a wavelength that is bigger than the length of the instrument itself,” explains Frank Steiner, a physicist at Ulm University in Germany.

The Arthur C. Clarke Gamma Ray Burst?

Larry Sessions, a columnist for Earth & Sky, has suggested in his blog that the gamma-ray event whose radiation reached us a few hours before Arthur C. Clarke died, and which occurred 7.5 billion light-years away, be named the Clarke Event. Even the faintest stars visible to the eye are merely hundreds or thousands of light-years distant, all well within our own Milky Way Galaxy. But staring toward the northern constellation Bootes on March 19th, even without binoculars or telescope you still could have witnessed a faint, brief, flash of light from this gamma-ray burst. The source of that burst has been discovered to lie over halfway across the Universe. The Gamma Ray Burst now holds the distinction of the most distant object that could be seen by the unaided eye and the intrinsically brightest object ever detected, the cosmic explosion is estimated to have been over 2.5 million times more luminous than the brightest known supernova.

Site – http://science.slashdot.org

Astronomers vie to make biggest telescope

A telescope arms race is taking shape around the world. Astronomers are drawing up plans for the biggest, most powerful instruments ever constructed, capable of peering far deeper into the universe — and further back in time — than ever before.The building boom, which is expected to play out over the next decade and cost billions of dollars, is being driven by technological advances that afford unprecedented clarity and magnification. Some scientists say it will be much like switching from regular TV to high-definition. In fact, the super-sized telescopes will yield even finer pictures than the Hubble Space Telescope, which was put in orbit in 1990 and was long considered superior because its view was freed from the distorting effects of Earth’s atmosphere. But now, land-based telescopes can correct for such distortion. Just the names of many of the proposed observatories suggest an arms race: the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope, which was downsized from the OverWhelmingly Large Telescope. Add to those three big ground observatories a new super eye in the sky, NASA’s James Webb Space Telescope, scheduled for launch in 2013.

Site – http://www.cnn.com

The Universe within 1 billion Light Years

Galaxies and clusters of galaxies are not uniformly distributed in the Universe, instead they collect into vast clusters and sheets and walls of galaxies interspersed with large voids in which very few galaxies seem to exist. The map above shows many of these superclusters including the Virgo supercluster – the fairly minor supercluster of which our galaxy is just a minor member. The entire map is approximately 7 percent of the diameter of the entire visible Universe. Individual galaxies are far too small to appear on this map, each point represents a group of galaxies.

Site – http://www.ldps.ws

Big Brain Theory: Have Cosmologists Lost Theirs?

It could be the weirdest and most embarrassing prediction in the history of cosmology, if not science. If true, it would mean that you yourself reading this article are more likely to be some momentary fluctuation in a field of matter and energy out in space than a person with a real past born through billions of years of evolution in an orderly star-spangled cosmos. Your memories and the world you think you see around you are illusions. This bizarre picture is the outcome of a recent series of calculations that take some of the bedrock theories and discoveries of modern cosmology to the limit. Nobody in the field believes that this is the way things really work, however. And so in the last couple of years there has been a growing stream of debate and dueling papers, replete with references to such esoteric subjects as reincarnation, multiple universes and even the death of spacetime, as cosmologists try to square the predictions of their cherished theories with their convictions that we and the universe are real.

Site – http://www.nytimes.com

Biggest black hole in the cosmos discovered

The most massive known black hole in the universe has been discovered, weighing in with the mass of 18 billion Suns. Observing the orbit of a smaller black hole around this monster has allowed astronomers to test Einstein’s theory of general relativity with stronger gravitational fields than ever before. The black hole is about six times as massive as the previous record holder and in fact weighs as much as a small galaxy. It lurks 3.5 billion light years away, and forms the heart of a quasar called OJ287. A quasar is an extremely bright object in which matter spiralling into a giant black hole emits copious amounts of radiation. But rather than hosting just a single colossal black hole, the quasar appears to harbour two – a setup that has allowed astronomers to accurately ‘weigh’ the larger one.

Site – http://space.newscientist.com

Time Itself May Be Slowing Down

For a decade, scientists have puzzled over a surprising phenomenon: Supernovae stars viewed at extreme distances seem to be moving away from us faster than those nearby. Most researchers have assumed that the stars have somehow accelerated – or that, more precisely, the rate of the expansion of the post-Big Bang universe itself has accelerated over time. But hold on just a minute. A group of scientists from the University of the Basque Country in Bilbao, and Spain’s University of Salamanca have offered a different idea. Maybe it’s the passage of time itself that’s slowing down, they say. The distant galaxies only look like they’re accelerating because our deep-space telescopes are essentially looking back in time to see them, to when time was going faster.

Site – http://blog.wired.com

Largest ever telescope gets $200m to proceed

The prospect of a ground-based telescope that can directly see extrasolar planets, the earliest stellar systems and the birth of distant galaxies is nearing reality. The Gordon and Betty Moore Foundation has pledged $200m for the design and construction of the Thirty Metre Telescope (TMT), which is being developed by a consortium of astronomers in the US and Canada, including the California Institute of Technology and the University of California. As its name suggests, the TMT will consist of a mirror 30 m in diameter, giving it eight times the collecting area of any current telescope. But unlike conventional telescopes, the size of the mirror means that it will have to be split up into 492 individual hexagonal segments, all packed together into a curved honeycomb arrangement.

Site – http://physicsworld.com

Universe’s first stars may have been ‘dark stars’

The universe’s first stars may have been bloated behemoths powered by dark matter, suggests an intriguing, if speculative, new study. These ‘dark stars’ might have delayed the creation of heavy elements, which make up everything from planets to people, as well as cosmic reionisation, which made the universe transparent to light billions of years ago. Theorists believe the first stars formed in cradles of dark matter, condensing from clouds of gas until their cores became so dense that nuclear fusion ignited, preventing the cores from collapsing further. This could heat up the cloud so much that it would stop contracting, so that it was supported by the annihilation of dark matter rather than by nuclear fusion, like normal stars. Such a ‘dark star’ would be about as massive as the Sun and would glow at infrared wavelengths. But it would be much larger – depending on the mass of the neutralino used, the star could span anywhere from the distance between the Sun and Uranus in our solar system to nearly 60 times that size.

Site – http://space.newscientist.com

The 6 Most Important Experiments in the World

Scientists rely on computer models to understand the toughest concepts in science: the origin of the universe, the human brain, artificial life, the behavior of atoms, and the future climate of the planet. These are some of the most important experiments that are currently active in the world.

Site – http://discovermagazine.com