Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2004 January 20
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Unexpected Galaxy String in the Early Universe
Illustration Credit: Povilas Palunas (U. Texas) et al., NSF, NASA

Explanation: How could such a long string of galaxies form so early in the universe? Several new measurements of galaxies and clusters in the early universe are reporting structures involving galaxies and clusters that are larger than expected with the new standard "dark-energy" cosmology. The controversy centres on the inability of a dark-energy dominated universe to create such large structures. Fans of the old standard cosmology -- without weird but pervasive dark energy -- are hoping that these new measurements rule out the newly popular strange universe. Previously, however, data taken from several independent sources over the past few years has only appeared to bolster the bold new universe paradigm. A compromise is still possible if the new data is not typical or if the comparison computer simulations are not properly biased. Pictured above is a computer-generated illustration of a universe that shows a string of galaxies of the size measured. The size of the superimposed box is about 300 million light years on a side.

Tomorrow's picture: Martian Adirondack

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