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."