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Originally posted by jp1111
In 1987, the brightest supernova of history was recorded and confirmed by Hubble Space Telescope in the Large Magellanic Cloud, our neighbor. The mirror-imaged rings of this exploding star still remain a mystery.
Originally posted by E_T
They are propably some old gas bubble which was ejected to space in some point of star's life in supergiant phase. And is now lighted by result of supernova. (like lighthouse)
BERKELEY, CA -- By observing distant, ancient exploding stars, physicists and astronomers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory and elsewhere have determined that the universe is expanding at an accelerating rate -- an observation that implies the existence of a mysterious, self-repelling property of space first proposed by Albert Einstein, which he called the cosmological constant. This extraordinary finding has been named Science magazine's "Breakthrough of the Year for 1998."
The Supernova Cosmology Project, based at Berkeley Lab and headed by Saul Perlmutter of the Physics Division, shares the citation with the High-z Supernova Search Team led by Brian Schmidt of Australia's Mount Stromlo and Siding Spring Observatories. Both teams are international collaborations, with researchers in England, France, Germany, and Sweden among the members of the Supernova Cosmology Project.
Energy Secretary Bill Richardson expressed pride in the accomplishment on behalf of the Department of Energy (DOE), which funds the country's national laboratory system.
"This brilliant example of quality research by DOE-supported scientists represents an important advance in our understanding of the universe," Richardson said. "It's impressive payback, in terms of advancing human knowledge and developing promising new technologies, for this country's investment in basic science research."
Berkeley Lab Director Charles Shank concurs. "We are proud of Berkeley Lab's contributions to this dramatic accomplishment," he says. "This achievement is yet another example of how painstaking, imaginative, basic research can advance humankind's knowledge of our universe, with the promise of impacts on our lives that we can only begin to imagine." (See expanded quotes from Richardson and Shank.)
Says Perlmutter, "A DOE facility like Berkeley Lab is a unique place that brings together many different areas of expertise -- particle physicists, astrophysicists, computer scientists, and engineers were all vital to our program. Just as important, the Lab environment allows research to continue over a long time. We worked ten years before we finally got the answers to our questions."
A Special Kind of Supernova is the Key
The surprising discovery that the expansion of the universe is accelerating, and thus is likely to go on expanding forever, is based on observations of type Ia supernovae, very bright astronomical "standard candles" that all have the same intrinsic brightness. Thus how bright they appear reveals their distance.
By comparing the distance of these exploding stars with the redshifts of their home galaxies, researchers can calculate how fast the universe was expanding at different times in its history. Good results depend upon observing many type Ia supernovae, both near and far. Employing supercomputer facilities at the National Energy Research Scientific Computing Center (NERSC) located at Berkeley Lab, the Supernova Cosmology Project has fully analyzed the first 42 out of the more than 80 supernovae it has discovered, and more analysis is in progress.
Type Ia supernovae are rare -- in a typical galaxy they may occur only two or three times in a thousand years -- and to be useful they must be detected while they are still brightening. Before the Supernova Cosmology Project employed search techniques developed during the first five years of its existence, finding supernovae was a haphazard proposition, which made it difficult to secure telescope time to observe them.
"It was a chicken and egg problem," says Perlmutter. "To get telescope time, you had to guarantee you were going to find a supernova. But without time on a major telescope, it was impossible to show that they were there, and that we could find them." Then, in the early 1990s, the group developed a new strategy that assured discovery of numerous supernovae "on demand."
What is this mystery force?
Cosmologists have proposed that it derives from dark energy—a substance whose properties and origin scientists have only begun to explore. At stake is more than just a better understanding of the fate of the universe: The very presence of dark energy may enable scientists to explain the fundamental forces of the universe and tease out the hidden connections among them.
Says Albrecht: "This is the most exciting endeavor going on in physics right now."
Probing dark energy, the energy in empty space causing the expanding universe to accelerate, calls for accurately measuring how that expansion rate is increasing with time. Dark energy is thought to drive space apart.
Astronomers used NASA's Hubble Space Telescope to hunt for supernovae (an energetic explosive event that occurs at the end of a star's lifetime), using their brightness, astronomers could measure if the universe was expanding faster or slower in the distant past.
In its search, Hubble discovered 42 new supernovae, including six that are among the most distant ever found. The farthest supernovae show that the universe was decelerating long ago, but then "changed gears" and began to accelerate.
In February, the team published results of Hubble Space Telescope observations that spanned a range of distances and periods in the universe's history. They found the period, some 6 billion years ago, when the shift occurred from a slowdown in the rate of expansion to an acceleration — a turning point that has become known as the "big jerk." The team used the light from a powerful "standard candle" — a type of exploding star, or supernova — to gauge distance. Then they used spectrographic data on these objects to determine the speed at which the galaxies containing the supernovae were receding.
A third major contribution came last year from a set of studies involving the cosmic microwave background measurements from a NASA satellite and observations from the Sloan Digital Sky Survey. Both pointed to dark energy as the dominant ingredient in the universe's recipe. And by combining data from the two, four teams working independently found evidence for the action of dark energy on the scale of galaxy clusters, which cover a huge expanse of space and embrace from 50 to 1,000 galaxies.
Recent theoretical explorations may suggest another approach to the physics of the vacuum. Some physicists have speculated that the invisible gravitating dark matter could be the other side of the invisible dark energy coin, and that suggests the possibility of manipulating the vacuum for energy release. If a controllable parameter could be found to mediate the balance between the invisible dark forces, the result would unleash the vacuum energy of creation in all of its awful power and majesty.
If it were possible to control the dark sides of the force then spacetime, the arena where everything we know takes place, could be bent and twisted with infinitely greater ease than was ever suspected. This would open Pandora's box to everything from vacuum energy weapons of mass destruction (capable of destroying the universe!) to spacetime warp drives and time machines.