ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Thursday, February 29, 1996 TAG: 9602290025
SECTION: EXTRA PAGE: 4 EDITION: METRO
SOURCE: FAYE FLAM KNIGHT-RIDDER/TRIBUNE
Earlier this month, when a group in Hawaii detected the most remote galaxy ever discovered - about 14 billion light-years away - they were, in essence, catching a glimpse of the universe as it looked 14 billion years ago.
That's because it took that long for the light to travel from this yet-unnamed galaxy to our telescopes here on Earth.
Considering the universe is 15 billion to 20 billion years old, this takes us most of the way back to the Big Bang.
``It's like having a time machine,'' says Princeton astrophysicist James Peebles. ``We can see into the past, and see things as they were when they were much younger.''
Two of the best time machines around are the giant Keck telescope in Hawaii, which spotted the 14 billion-year-old galaxy, and the Hubble Space Telescope, which last month peeled back our view by revealing intricate spiral and oblong shapes of distant galaxies previously visible only as faint smudges.
What these pictures reveal is a dynamic universe, evolving slowly from a time when exotic objects - brilliant quasars and odd-shaped galaxies - could be found.
``The story that's been emerging is that at very early times there are examples of ordinary galaxies, as well as very strange beasts - amorphous galaxies, galaxies with hot spots, objects shaped like a necklace,'' said astronomer Anthony Tyson of AT&T Bell Laboratories in Murray Hill, N.J.
Some of these, he says, may be glimpses of the dawn of the universe, when helium and hydrogen from the Big Bang were being swept up into the first stars and galaxies.
Beyond that, there would be no more galaxies to be seen. ``We may be nearing in some sense the edge of the observable universe.''
The reason distant objects take us back in time has to do with the speed of light, 186,000 miles per second, which, while fast, is not instantaneous.
If a star is 50 light-years away, light it emitted in 1946 is just reaching us now. If the star exploded last year, we wouldn't know it until 2045.
The bright objects the telescopes are seeing billions of light-years away are not individual stars but entire galaxies - collections of stars that from our great distance appear as single points of light. (The stars we see when we look up at night are all within our own galaxy, the pinwheel-shaped Milky Way).
Until the observations of the last several months, the farthest objects observed were faint blurs thought to be galaxies, or unusually luminous objects called quasars. Quasars are visible from the very fringes of the visible universe because they are many times brighter than galaxies.
It was a quasar that helped scientists use the Keck telescope to detect a galaxy 14 billion light-years away. The galaxy absorbed some of the light from this quasar, and by studying the pattern of light absorption, astronomers were able to deduce the galaxy's distance without actually seeing it.
For pictures, astronomers are looking to the Hubble telescope, whose repair in 1993 has given it the sharp vision they had hoped for.
In December, astronomers captured the best images to date showing the distant universe. They did it by training the Hubble telescope on a patch of black, desolate space near the handle of the Big Dipper.
After 10 days of exposure, the view filled with spirals, ovals and smudges of blue, white and yellow light.
Since the photographs were released last month, other astronomers have determined already that six of the faintest galaxies are shining at us from the first billion years of the universe's 15 billion-year history.
``It's like an archaeological dig,'' says Williams.
Though it was widely reported that the survey revealed 40 billion more galaxies than astronomers had seen before, Williams and other astronomers are in disagreement over that estimate.
The Hubble telescope actually photographed only a thousand or so galaxies, but by assuming that all sections of the sky had a comparable number of galaxies, the astronomers calculated how many the entire visible universe contained.
``It's like looking at a room through a straw,'' explains Kenneth Brecher, an astronomer at Boston University. ``You have to assume the room looks the same whichever direction you aim the straw.''
From the Hubble image alone, astronomers can't tell how far away the galaxies are. To get distance estimates, they are turning to the Keck - the world's largest telescope, with a mirror about 33 feet in diameter - atop the 13,796-foot-high extinct volcano called Mauna Kea, on the big island of Hawaii.
Using the Keck, astronomers measure distances to galaxies using an indirect method that involves calculating the speed the galaxies are traveling.
It could take months or even years, but if astronomers can measure distances to enough galaxies photographed by Hubble, they may be able to tell whether we are reaching back to the beginning of galaxy formation. If they reach that point, they expect to see fewer galaxies as distances increase.
LENGTH: Medium: 91 lines ILLUSTRATION: GRAPHIC: KRT: Time travel, by telescope.by CNB