From the April 2009 issue

Could large numbers of black holes account for much of the “dark matter” estimated to exist in our universe?

Jeff Wise, Louisville, Kentucky
By | Published: April 27, 2009
This Hubble Space Telescope composite image shows a ghostly “ring” of dark matter in the galaxy cluster ZwCl0024+1652.
NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

No, because the universe never had the raw material to grow enough black holes to account for current estimates of dark matter.