Dark matter could be an entire dark sector of the universe, with its own particles and forces.

By Kathryn Zurek edited by Clara Moskowitz

Have you ever stood by the sea and been overwhelmed by its vastness, by how quickly it could roll in and swallow you? Evidence suggests that we are suspended in a cosmic sea of dark matter, a mysterious substance that shapes galaxies and large structures in the universe but is transparent to photons, the carriers of the electromagnetic force. Our galactic home, the Milky Way, is submerged in dark matter, but this hidden body but does not devour us, because its forces cannot touch the regular matter we’re made of.