What is a ‘Halo’ that was detected by NASA’s Hubble Telescope?

Recently NASA’s Hubble Telescope for the first time ever signalled the presence of a giant halo of gas found surrounding the Milky Way’s closest galactic neighbour – the Andromeda galaxy. Halo is nothing but a huge scattering of gas which is usually found surrounding the celestial bodies. Also known as M31, the Andromeda galaxy is ..