Giant Halo Around The Andromeda Galaxy Found
The Andromeda galaxy is our nearest galactic neighbor in space. Though it is 2.5 million light-years away, its spiral of over 100 billion stars makes it visible as a cigar-shaped smudge of light high in the autumn sky. But there is also something that takes Hubble to notice - a huge bubble of hot, diffuse plasma surrounding it. If we could see that gargantuan halo from Earth, it would appear to be 100 times the angular diameter of the full Moon. The gargantuan halo can be thought of as the "atmosphere" of a galaxy and is estimated to contain half the mass of the stars in the Andromeda galaxy itself. Astronomers were able to identify the halo by measuring how it filtered the light of distant bright background objects called quasars. read more