ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, February 25, 1996 TAG: 9602260100
SECTION: NATIONAL/INTERNATIONAL PAGE: A-10 EDITION: METRO
DATELINE: LOS ANGELES
SOURCE: JANE E. ALLEN ASSOCIATED PRESS
NEW TECHNIQUE lets astronomers see billions of years of a galaxy's development in minutes.
Astronomers have used a new technique to identify the most distant group of infant galaxies spotted yet, giving us an idea of how our own Milky Way may have appeared when it was very young.
The universe is thought to have been created by the Big Bang about 15 billion years ago. To help understand what followed, astronomers try to look back in time by looking into deep space, where light now seen on Earth originated billions of years ago.
While other teams have made indirect observations of extremely distant galaxies, these researchers were able to make direct observations of 23 galaxies as they appeared soon after they formed, about 12.8 to 13.5 billion years ago.
``We know that at some point in the early history of the universe, galaxies came together and formed out of a primordial soup. Until now, we really didn't know exactly when that happened,'' said Chuck Steidel, an assistant astronomy professor at the California Institute of Technology in Pasadena.
``For the first time, we can actually study what an average galaxy looked like at a time soon after its formation,'' he said Friday in an interview from an observatory atop Mount Palomar.
The new technique allows observations through a range of depths in the universe, rather than a single distance. On some nights, they have been able to find 30 to 40 galaxies in the same section of sky.
``We've found a means of discovering an entire population of galaxies, rather than just one or two,'' Steidel said.
The research has been accepted for publication this spring in Astrophysical Journal Letters, a journal of the American Astronomical Society.
Galaxies are round or football-shaped conglomerations of 10 billion to 100 billion stars formed when interstellar gas collapses.
Astronomers dated the galaxies using a technique that takes images of the sky with filters that only let through particular wavelengths of light.
The galaxies could be seen through red filters and green filters. But when ultraviolet filters were used, the galaxies disappeared. That provided an indication of distance, which correlates to age in astronomy.
The astronomers next used a stronger telescope to determine more precisely the galaxies' distance and age.
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