Astronomers Confirm 300-Million-Light-Year Boötes Void as 1 of 100 High-Significance Cosmic Voids
Updated
Updated · spacedaily.com · Aug 3
Astronomers Confirm 300-Million-Light-Year Boötes Void as 1 of 100 High-Significance Cosmic Voids
2 articles · Updated · spacedaily.com · Aug 3
Summary
A 2025 Bayesian catalogue placed the Boötes Void among 100 high-significance nearby voids, listing it as entry 88 with a radius of 39.5 megaparsecs per h, plus or minus 2.9.
Redshift surveys established that status after finding a stark galaxy deficit: the 1981 discovery saw just 1 galaxy where about 25 were expected, and a 1987 follow-up found 0 where 31 were predicted.
Modern estimates put the void at 250 to 330 million light-years across and about 700 million light-years away; surveys have found roughly 60 galaxies inside a volume that rough density rules suggest could host about 2,000.
Those galaxies cluster in a tube-like structure, supporting the idea that Boötes formed from smaller voids that merged rather than from a single perfectly empty cavity.
Later infrared work helped recast Boötes as not anomalously empty but an unusually large example of a common cosmic structure, making such voids useful probes of dark energy and gravity.