The Milky Way galaxy weighs about 1 trillion times as much as our sun, according to a new estimate.
Previous estimates had ranged from 750 billion solar masses to up to 2 trillion. Lately, researchers have been leaning toward the higher figure. But now astronomers have used a more refined method to conclude that our galaxy's mass is slightly less than 1 trillion solar masses.
More: http://www.space.com/scienceastronomy/080527-milky-way.html