Research News

Astronomy: Ancient Galaxy Walls Go Up; Will Theories Tumble Down?

Science  04 Apr 1997:
Vol. 276, Issue 5309, pp. 36
DOI: 10.1126/science.276.5309.36

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Summary

IRVINE, CALIFORNIA--New observations described at a National Academy of Sciences colloquium here suggest that giant walls of galaxies, hundreds of millions of light-years long, may have crisscrossed the universe when it was just 15% of its present age. Such structures are similar to what we see today, which raises a problem for theorists: If gravity hasn't radically resculpted the universe over time, that implies that it may have far less mass than theorists prefer. That is in line with evidence of a scarcity of mass in the nearby universe but at odds with one measurement of how fast the cosmic expansion rate is changing, which hints at a much higher density of matter (see p. 37).