The vast „sheet“ of dark matter could explain why almost all of our galactic neighbors are running away from us.
The Milky Way — and in fact our entire galactic neighborhood known as the Local Group — appear to be lodged in a vast, extended “sheet” of dark matter flanked on each side by cosmic voids, new research suggests.
The findings, described in a new study published in Nature Astronomy, could help explain the puzzling motion exhibited by our nearby galaxies, which seems to defy the gravitational influence of neighboring realms.
The enigma ties in with the American astronomer Edwin Hubble’s discovery nearly a century ago that the universe is expanding. The discovery was made after Hubble noticed that nearly every galaxy he observed was moving away from the Earth at a speed directly proportional to its distance.
But there was one notable exception: Andromeda, the nearest major galaxy to ours, which was instead moving towards us. This was a head-scratcher, because Andromeda, the Milky Way, and dozens of other nearby galaxies are all gravitationally bound to each other, forming what’s known as the Local Group. The immense gravity of the Local Group should, in theory, be drawing all its constituent realms towards each other, and not just Andromeda.
