Experts Estimate Galaxy Count

ByABC News

A U S T I N,   Texas,   Jan. 7, 2001 -- Looking back in time at a tiny section of sky, the Hubble Space Telescope found there may be 125 billion galaxies in the universe, about 45 billion more than the last best estimate, astronomers reported today.

The new number was based on observations by the orbiting telescope’s Deep Field camera last October, when it looked at a speck-sized area of the southern sky, taking what amounts to a visual core sample of the heavens.

The Hubble telescope took a similar view of the northern sky in 1995, and then estimated that there might be 80 billion galaxies in existence.

Harry Ferguson of the Space Telescope Science Institute, which studies Hubble findings, said the southern observations looked a bit further into the past than the northern ones, and managed to detect dimmer objects in space, which accounts for the higher galactic count.

12 Billion Light Years Away

The Deep Field-South project looked 12 billion light years away in distance, back in time to a period perhaps one billion years after the theoretical big bang that astronomers believe created the universe.

Hubble’s glimpse of the southern sky took in an area that would appear to be “about the size of a grain of sand held at arm’s length,” Ferguson told reporters at the American Astronomical Society meeting in Austin.

But in that small segment of the sky, the telescope spied 620 galaxies. Scientists extrapolated from that sample to theorize that there might be 125 billion galaxies over the whole sky.

“Anybody could have predicted it,” Ferguson said, stressing that by looking further back in time, it was expected that more galaxies would turn up.

Weird-Shaped Galaxies

Ferguson and other astronomers at a news conference acknowledged that some of the newly detected galaxies were oddly shaped, unlike the symmetrical Milky Way that contains Earth and other more familiar galaxies that are shaped like spirals and ellipses.

These newly-spied galaxies appeared to be a disorganized collection of loosely-bound lumps. One astronomer likened their shape to a Danish pastry with raisins and another called one group of these galaxies “a pastry shop.”

The notion that there might be more galaxies than originally thought is grist for astronomers trying to figure out how the universe developed, especially in its earliest stages, Ferguson said.

Perhaps Ghost Galaxies, Too

Because these observations by Hubble could see very faint objects whose light made its journey toward Earth billions of years ago, it probably counted so-called ghost galaxies in its estimate.

Ghost galaxies are tiny, and consist of large amounts of mysterious dark matter. Since astronomers believe that 90 percent of the universe may be made up of dark matter, that makes the ghosts worth studying and new astronomical instruments make this possible.

A light year is the distance light travels in a year, about 6 trillion miles.

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