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Scientists find oldest supernova yet, discovery could help explain why universe is accelerating

By Marshall Connolly, Catholic Online (NEWS CONSORTIUM)
January 11th, 2013
Catholic Online (www.catholic.org)

Scientists from UC Berkley's Supernova Cosmology Project are announcing the discovery of the oldest supernova yet, having located it with the Hubble Space telescope at a distance of 10 billion light years. This discovery will provide astronomers with added data that may help them to solve one of the universe's greatest mysteries.

LOS ANGELES, CA (Catholic Online) - The ancient supernova occurred some 10 billion years ago, long before the formation of the Sun and Earth. However because it is so distant, it has taken 10 billion years for its light to reach us. That fact may provide astronomers with an important clue they can use to solve a perplexing mystery.

Astronomers know the universe is expanding in all directions, simultaneously, much like a balloon being inflated. Edwin Hubble discovered this in the 1920s when he studied the light from distant galaxies and found they were receding from us.

What astronomers recently discovered, and now poses one of the greatest mysteries, is that this rate of expansion is accelerating rather than slowing down or holding constant.

Astronomers compare this to an explosion that become more violent as it continues, rather than slowing down. It is a counter-intuitive mystery they are yet to solve.

However, both astronomers and physicists are working quite hard to unravel the mystery. One way astronomers can contribute is to measure distant objects. Certain types of supernovas, known as type IA supernovae, are excellent objects for astronomers to measure because they are uniformly bright.

A supernova is the explosive death of a star that occurs when a star has used all of the hydrogen fuel in its core and no longer has enough fuel to continue shining. The breakdown of atomic fusion in its core causes the outer shell of the star to collapse which in turn causes a uniform explosion in all directions. Stars of different masses produce different kinds of explosions, but type IA supernovas are uniform and equally bright in all directions. This allows them to be used to make precise measurements of distance.

Astronomers refer to them as "standard candles" since they serve as one of the several well-understood objects that can be accurately measured.

When the Berkeley astronomers found a Type IA supernovae 10 billion light-years distant, they knew they had an incredible find. The find now allows them to measure the distance to the object which they can compare to the expansion rate of the universe to create a data point. That data point can then be used to compare various theories of expansion and evaluate which ones serve to best account for the expansion rate of the universe.

In all, it's just a little more information than they had before. The team hopes to discover and measure several other similar objects to create a database of information that may help cosmologists settle on the mathematical model which best explains the accelerating universe.

For now, the mystery remains, but today, it's one step closer to being solved.

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