The nearest spiral galaxy to ours, which will one day collide with us spelling our fiery doom, is riddled with black holes each one sucking in and destroying unimaginable amounts of matter.
NASA's Chandra X-ray Observatory have identified 26 black hole candidates - though astronomers think this is "just the tip of the iceberg".
Although black holes are invisible, they can be detected by looking for material sucked in from nearby stars that leaves a burst of radiation as it disappears.
Measurements were taken over 13 years to ensure that what was being observed was in fact evidence of black holes.
Michael Garcia of f Harvard-Smithsonian Center for Astrophysics (CfA) said: "By observing in snapshots covering more than a dozen years, we are able to build up a uniquely useful view of M31.
"The resulting very long exposure allows us to test if individual sources are black holes or neutron stars."
The number of black holes is far more than that found in our own galaxy.
Stephen Murray of Johns Hopkins University and CfA, said: "When it comes to finding black holes in the central region of a galaxy, it is indeed the case where bigger is better.
"In the case of Andromeda we have a bigger bulge and a bigger supermassive black hole than in the Milky Way, so we expect more smaller black holes are made there as well."
These results will be published in the June 20 issue of The Astrophysical Journal. Many of the Andromeda observations were made within Chandra's Guaranteed Time Observer program.Suggest a correction