Galaxies Found from Ancient Universe

April 30, 2008 01:23 PM
by findingDulcinea Staff
A team of scientists has found nine young, ultradense galaxies of the type that form the building blocks of today’s largest star systems.

30-Second Summary

Because the light from the nine faraway galaxies has taken 11 billion years to reach Earth, “what we see now is the way these compact galaxies existed 11 billion years ago, when the universe was less than 3 billion years old,” explained study leader Pieter G. van Dokkum of Yale.

Using NASA’s Hubble Space Telescope and the W.M. Keck Observatory on Mauna Kea, the astronomers were able to observe some of the mysterious characteristics of these galaxies from the past.

For instance, although they are a fraction of the size of the “mature” galaxies seen today, they comprise about the same number of stars. That means that the compact systems “are the equivalent of a human baby that is 20 inches long, yet weighs 180 pounds,” Science Daily reports.

The extreme density of the systems poses a mystery for astronomers, because “it is not yet clear how one of these would build itself up to the size of the galaxies we see today,” van Dokkum said.

However, that didn’t stop the study leader from speculating that the galaxies were formed during an interaction between hydrogen gas and dark matter—the invisible matter that makes up the majority of the universe.

Despite the questions posed by this recent study, astronomers have been making great advancements in the study of the ancient universe. In early April, the Royal Astronomical Society announced that it had produced the most sensitive map of the distant universe ever, allowing scientists to look at more than 100,000 galaxies from 10 billion years ago.

Headline Link: ‘Ultra-dense Galaxies Found in Early Universe’

Background: ‘Witnessing the Formation of Distant Galaxies’

Reference: Hubble, W.M. Keck and dark matter

Related Topic: FindingDulcinea’s Web Guide to Astronomy


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