Scientists have observed a gigantic gas halo stretching from Andromeda – our nearest major galaxy. It goes towards our own Milky Way and if it could be seen with the naked eye, it would be the diameter of 100 full moons.
Halos are the gaseous atmospheres of galaxies. Astrophysicist Nicolas Lehner of the University of Notre Dame, Indiana, who led the study, explains that the properties of these gaseous halos control the rate at which stars form in galaxies.
Andromeda, also known as Messier 21, or M31, is our closest major galactic neighbor, at 2.5 million light-years away. It is also 25 percent more luminous than the Milky Way and contains about 1 trillion stars, twice as much as the greater estimates for our own galaxy.
Both Andromeda and the Milky Way are part of a cluster called the Local Group, containing about 45 other major galaxies that we know of.
The scientists said that if the halo could be viewed with the naked eye, it would be 100 times the diameter of the full moon , while Andromeda galaxy looks about six times the diameter of the full moon.
he halo which appeared to be about six times larger and 1,000 times more massive than previously thought, stretches about 1 million light years from Andromeda, halfway to the Milky Way. Scientists say it contains as much mass in its diffuse gas as half of the stars in the Andromeda Galaxy. But the gas is invisible, that is unless you find a bright enough background object in the universe whose light is affected by the intervening gas in the halo. The most convenient one is a quasar, a star-like object.
The quasar’s extreme luminosity allows researchers to measure the difference in the intensity of its glow, much in the same way scientists look for planets orbiting distant stars.
Read more: http://rt.com/usa/256945-andromeda-galaxy-halo-quasar/