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Census Finds Universe Has Ten Times More Galaxies

By David Reneke

The universe has ten times more galaxies than previously thought, and the Earth may have had more than one moon.

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Astronomers using data from the NASA/ESA Hubble Space Telescope and other telescopes have performed an accurate census of the number of galaxies in the universe, and concluded that there are at least 10 times as many galaxies in the observable universe as previously thought. The results have clear implications for our understanding of galaxy formation, and also help solve an ancient astronomical paradox – why is the sky dark at night?

One of the most fundamental questions in astronomy is how many galaxies the universe contains. The Hubble Deep Field images, captured in the mid-1990s, gave the first real insight into this. Myriad faint galaxies were revealed, and it was estimated that the observable universe contains 100–200 billion galaxies.

Now, an international team led by Christopher Conselice of the University of Nottingham has painstakingly converted the Hubble images into 3D in order to make accurate measurements of the number of galaxies at different times in the universe’s history. In addition, they used new mathematical models that allowed them to infer the existence of galaxies that the current generation of telescopes cannot observe.

This led to the surprising realisation that in order for the numbers to add up, some 90% of the galaxies in the observable universe are actually too faint and far away to be seen right now.

In analysing...

The full text of this article can be purchased from Informit.