Out in deepest space lurks a force of almost unimaginable power. Explosions of extraordinary violence, are blasting through the Universe every day. If one ever struck our Solar System it would destroy our Sun and all the planets.
For years no one could work out what was causing these awesome explosions. Now scientists think they have identified the culprit. It's the most extreme object ever found in the Universe; they have christened it a 'hypernova'.
The death star.
Showing posts with label Astrophysics. Show all posts
Showing posts with label Astrophysics. Show all posts
Wednesday, June 25, 2008
Thursday, May 1, 2008
The Hawking Paradox.
A documentary about the universe and Stephen Hawkings role in understanding it. But behind the public face lies an argument that has been raging for almost 30 years.
In 1976 he published a paper in Physical Review D called, "The breakdown of predictability in gravitational collapse". In this paper, Hawking argued that it wasn't just the black hole that disappeared.
He said that all the information about everything that had ever been inside the black hole disappeared, too. In everyday life, we're used to losing information - but according to physics this isn't supposed to happen; according to physics, information is never really lost, it just gets harder to find.
The reason physicists cling on to the idea that information can't be lost is that it's their link with either the past or the future. If information is lost then science can never know the past or predict the future. There are limits to what science can know.
Since then the "information paradox" has come to be seen as one of the most fundamental and most difficult problems in physics.
The Hawking Paradox.
In 1976 he published a paper in Physical Review D called, "The breakdown of predictability in gravitational collapse". In this paper, Hawking argued that it wasn't just the black hole that disappeared.
He said that all the information about everything that had ever been inside the black hole disappeared, too. In everyday life, we're used to losing information - but according to physics this isn't supposed to happen; according to physics, information is never really lost, it just gets harder to find.
The reason physicists cling on to the idea that information can't be lost is that it's their link with either the past or the future. If information is lost then science can never know the past or predict the future. There are limits to what science can know.
Since then the "information paradox" has come to be seen as one of the most fundamental and most difficult problems in physics.
The Hawking Paradox.
Friday, April 18, 2008
Most of our universe is missing.
Most of our Universe is missing.
Dark matter and dark energy are two of the most vexing problems in science today. Together they dominate the universe, comprising some 96 percent of all mass and energy. But nobody knows what either is.
Dark matter was invoked decades ago to explain why galaxies hold together. Given regular matter alone, galaxies might never have formed, and today they would fly apart. So there must be some unknown stuff that forms invisible clumps to act as gravitational glue.
Dark energy hit the scene in the late 1990s when astronomers discovered the universe is not just expanding, but racing out at an ever-faster pace. Some hidden force, a sort of anti-gravity, must be pushing galaxies apart from one another in this accelerated expansion.
Richard Muller - the big bang, dark matter, dark energy.
Dark matter and dark energy are two of the most vexing problems in science today. Together they dominate the universe, comprising some 96 percent of all mass and energy. But nobody knows what either is.
Dark matter was invoked decades ago to explain why galaxies hold together. Given regular matter alone, galaxies might never have formed, and today they would fly apart. So there must be some unknown stuff that forms invisible clumps to act as gravitational glue.
Dark energy hit the scene in the late 1990s when astronomers discovered the universe is not just expanding, but racing out at an ever-faster pace. Some hidden force, a sort of anti-gravity, must be pushing galaxies apart from one another in this accelerated expansion.
Richard Muller - the big bang, dark matter, dark energy.
Sunday, April 6, 2008
Cosmological origins: the universe, galaxies, and stars.
The March 13, 2007 Volunteer Enrichment Committee lecture at the Denver Museum of Nature & Science by Curator of Space Science Dr. Ka Chun Yu.
This lecture covers the 13.7 billion year history of the Universe, including topics on cosmology (relativity, the expansion of the universe, the aftermath of the Big Bang, inflation, the cosmic microwave background radiation, formation of the elements), and the evolution of the universe's contents afterwards (large structure formation, the evolution of galaxies, the roles of dark matter and dark energy). The talk ends with star formation covering molecular clouds.
Cosmological origins: the universe, galaxies, and stars.
This lecture covers the 13.7 billion year history of the Universe, including topics on cosmology (relativity, the expansion of the universe, the aftermath of the Big Bang, inflation, the cosmic microwave background radiation, formation of the elements), and the evolution of the universe's contents afterwards (large structure formation, the evolution of galaxies, the roles of dark matter and dark energy). The talk ends with star formation covering molecular clouds.
Cosmological origins: the universe, galaxies, and stars.
Saturday, April 5, 2008
The big question...
In this 20 min program narated by Stephen Hawking, we take look at the origin of the universe as is understood by modern science and largely thanks to Hawking's contribution to this field of research.
The big question - How did the universe begin?
The big question - How did the universe begin?
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