The death of the universe - Renée Hlozek

Published on Dec 12, 2013

View full lesson: http://ed.ted.com/lessons/the-death-o...

The shape, contents and future of the universe are all intricately related. We know that it's mostly flat; we know that it's made up of baryonic matter (like stars and planets), but mostly dark matter and dark energy; and we know that it's expanding constantly, so that all stars will eventually burn out into a cold nothingness. Renée Hlozek expands on the beauty of this dark ending.

Lesson by Renée Hlozek, animation by Giant Animation Studios.

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NASA sees 'watershed' cosmic blast in unique detail

Posted: Nov 21, 2013 by Francis Reddy

In the most common type of gamma-ray burst, illustrated here, a dying massive star forms a
black hole (left), which drives a particle jet into space.
Credit: NASA's Goddard Space Flight Center

(Phys.org) —On April 27, a blast of light from a dying star in a distant galaxy became the focus of astronomers around the world. The explosion, known as a gamma-ray burst and designated GRB 130427A, tops the charts as one of the brightest ever seen

A trio of NASA satellites, working in concert with ground-based robotic telescopes, captured never-before-seen details that challenge current theoretical understandings of how gamma-ray bursts work.

"We expect to see an event like this only once or twice a century, so we're fortunate it happened when we had the appropriate collection of sensitive space telescopes with complementary capabilities available to see it," said Paul Hertz, director of NASA's Astrophysics Division in Washington.

Gamma-ray bursts are the most luminous explosions in the cosmos, thought to be triggered when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star and erupt into space at nearly the speed of light.

Gamma-rays are the most energetic form of light. Hot matter surrounding a new black hole and internal shock waves produced by collisions within the jet are thought to emit gamma-rays with energies in the million-electron-volt (MeV) range, or roughly 500,000 times the energy of visible light. The most energetic emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when the jet slams into its surroundings, forming an external shock wave.

The Gamma-ray Burst Monitor (GBM) aboard NASA's Fermi Gamma-ray Space Telescope captured the initial wave of gamma rays from GRB 130427A shortly after 3:47 a.m. EDT April 27. In its first three seconds alone, the "monster burst" proved brighter than almost any burst previously observed.

Continue Learning: http://phys.org/news/2013-11-nasa-watershed-cosmic-blast-unique.html
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NASA's Chandra Helps Confirm Evidence of Jet in Milky Way's Black Hole

Nov. 20, 2013

Composite image of Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way.
Image Credit: X-ray: NASA/CXC/UCLA/Z. Li et al; Radio: NRAO/VLA

Astronomers have long sought strong evidence that Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is producing a jet of high-energy particles. Finally they have found it, in new results from NASA's Chandra X-ray Observatory and the National Science Foundation's Very Large Array (VLA) radio telescope.

Previous studies, using a variety of telescopes, suggested there was a jet, but these reports -- including the orientation of the suspected jets -- often contradicted each other and were not considered definitive.

"For decades astronomers have looked for a jet associated with the Milky Way's black hole. Our new observations make the strongest case yet for such a jet," said Zhiyuan Li of Nanjing University in China, lead author of a study appearing in an upcoming edition of The Astrophysical Journal and available online now.

Jets of high-energy particles are found throughout the universe, on large and small scales. They are produced by young stars and by black holes a thousand times larger than the Milky Way's black hole. They play important roles in transporting energy away from the central object and, on a galactic scale, in regulating the rate of formation of new stars.

"We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole's spin axis. This gives us important clues about the growth history of the black hole," said Mark Morris of the University of California at Los Angeles, a co-author of the study.

The study shows the spin axis of Sgr A* is pointing in one direction, parallel to the rotation axis of the Milky Way, which indicates to astronomers that gas and dust have migrated steadily into Sgr A* over the past 10 billion years. If the Milky Way had collided with large galaxies in the recent past and their central black holes had merged with Sgr A*, the jet could point in any direction.

Continue Learning: http://www.nasa.gov/mission_pages/chandra/news/high-energy-particles-in-milky-way.html#.Uo0-CfmKK-0

Through the Wormhole: Are We Alone?

Through the Wormhole: Are We Alone?

Aliens almost certainly do exist. So why haven't we yet met E.T.? It turns out we're only just developing instruments powerful enough to scan for them, and science sophisticated enough to know where to look. As a result, race is on to find the first intelligent aliens.

But what would they look like, and how would they interact with us if we met? The answers may come to us sooner than we imagine, for one leading astronomer believes she may already have heard a hint of their first efforts to communicate.

http://science.discovery.com

Through the Wormhole: How Did We Get Here?

Everywhere we look, life exists in both the most hospitable of environments and in the most extreme. Yet we have only ever found life on our planet. How did the stuff of stars come together to create life as we know it? What do we really mean by 'life'? And will unlocking this mystery help us find life elsewhere?

http://science.discovery.com

Through the Wormhole: The Riddle of Black Holes

Through the Wormhole: The Riddle of Black Holes

They are the most powerful objects in the universe. Nothing, not even light, can escape the gravitational pull of a black hole. Astronomers now believe there are billions of them out in the cosmos, swallowing up planets, even entire stars in violent feeding frenzies. New theoretical research into the twisted reality of black holes suggests that three-dimensional space could be an illusion. That reality actually takes place on a two-dimensional hologram at the edge of the universe.

http://science.discovery.com