Mizar and Alcor's proper motions show they move together, along with most of the other stars of the Big Dipper except Alpha Ursae Majoris and Eta Ursae Majoris, as members of the Ursa Major Moving Group, a mostly dispersed group of stars sharing a common birth. However, it has yet to be demonstrated conclusively that they are gravitationally bound. Gaia parallax measurements indicate that the Alcor binary and Mizar quadruple are somewhat closer together than previously thought: . The uncertainty is due to our uncertainty about the exact distances from us. If they are exactly the same distance from us then the distance between them is only .