Spiral galaxies are perhaps the most fascinating structures in astronomy, yet their nature is still a mystery. Astronomers currently have two categories of theories that can explain this structure, depending on the environment of the galaxy, but a new study suggests that one of these theories may be wrong.
For galaxies with nearby companions, astronomers theorize that tidal forces may pull out the spiral structure. But for isolated galaxies, another mechanism is required in which galaxies form these structures without intervention from a neighbor.
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Precise measurements on the light from distant quasars suggest that the value of the fine-structure constant may have changed over the history of the Universe. If the quasar results are eventually confirmed, our concepts of space and time are sure to change our fundamental understanding of the Universe.
The fine-structure constant, or alpha, is the coupling constant for the electromagnetic force. If alpha were just 4% bigger or smaller than it is, stars wouldn't be able to make carbon and oxygen, which would have made it impossible for life as we know it in our Universe to exist.
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This new Spitzer Space Telescope infrared image has revealed a dark cloud called M17 SWex that is forming stars at a furious rate but has not yet spawned the most massive type of stars, known as O stars. Such stellar behemoths, however, light up the M17 nebula at the image's center and have also blown a huge "bubble" in the gas and dust that forms M17's luminous left edge.
Continue reading "Image of the Day: Luminous Objects in Sagittarius Arm of the Milky Way" »
A team at the University of Pittsburg fashioned ring-shaped networks of brain cells that were not only capable of transmitting an electrical impulse, but also remained in a state of persistent activity associated with memory formation, according to lead researcher Henry Zeringue, a bioengineering professor in Pitt's Swanson School of Engineering.
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By examining infrared images taken by NASA satellites, Sarah Parcak and her team from the University of Alabama at Birmingham identified pyramids buried deep under the ancient Egyptian city of Tanis, Egypt. Tanis, abandoned centuries ago, is famous as the fictional home of the Lost Ark from the Indiana Jones movies. Satellite images also showed other lost structures, like tombstones and houses, buried for thousands of years.
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The human race will find life elsewhere in the Universe as it pushes ahead with space exploration, reported astronauts of the space shuttle Endeavour. The US space shuttle Endeavour prepares today to undock from the International Space Station and jet back to Earth, wrapping up its final journey before entering retirement, NASA said.
"If we push back boundaries far enough, I'm sure eventually we'll find something out there," said Mike Foreman, a mission specialist on the Endeavour, "Maybe not as evolved as we are, but it's hard to believe that there is not life somewhere else in this great Universe," he added.
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NASA's Hubble Space Telescope has found a rare class of oddball stars called blue stragglers in the hub of the Milky Way -- the first detected within our galaxy's bulge. Blue stragglers seemingly lag behind other stars in the aging process, appearing younger than the population from which they formed. While they have been detected in many distant star clusters, and among nearby stars, they never have been seen inside the Milky Way core.
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Dark matter not only had a role to play in fueling early primitive stars, it may have created "dark stars" so massive that they went on to spawn supermassive black holes found at the cores of the one trillion galaxies estimated to populate the universe.
NGC 4151, the Eye of Sauron, shown above, is one of the nearest galaxies to Earth to contain an actively-growing black hole the center of this active galaxy 43 million light years away from Earth. Scientists believe powerful X-rays generated by the super-massive black hole produced the bright blue ‘pupil’ of the eye caused by matter falling into the black hole.
Continue reading "The Central Black Holes of a Trillion Galaxies --Were They Spawned by Supermassive Dark Stars? " »
“Our own Universe may be the interior of a black hole existing in another universe.” In a remarkable paper about the nature of space and the origin of time, Nikodem Poplawski, a physicist at Indiana University, suggests that a small change to the theory of gravity implies that our Universe inherited its arrow of time from the black hole in which it was born.
Poplawski says that the idea that black holes are the cosmic mothers of new universes is a natural consequence of a simple new assumption about the nature of spacetime. Poplawski points out that the standard derivation of general relativity takes no account of the intrinsic momentum of spin half particles. However there is another version of the theory, called the Einstein-Cartan-Kibble-Sciama theory of gravity, which does.
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The new 2MASS Redshift Survey (2MRS) mapCovering 95 per cent of the sky in the infrared part of the spectrum, shows the distribution of galaxies and dark matter that make up the local Universe up to 380 million light years away. The map also shows more distant objects. The purple areas denote galaxies closest to Earth, whist the red areas are the furthest, lying about 1 billion light years from Earth.
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