British astronomers say they have observed the biggest star ever seen in the universe. They have found out that the star is twice as big as any seen before, more than 250 times the mass of the sun, and millions of times brighter. Researchers are stunned by the colossal nature of a group of stars they have just seen with a very large telescope facility in Chile. The UK lead team behind the discovery says the mass and brightness of these objects go well beyond what many thought was even possible. One of the new stars, known simply as R136a1, is twice as big as anything seen before, and millions of times brighter than the sun. It is unlikely to have any planets around it however, simply because planets take longer to form than this star will be in existence. Its brief but brilliant life should end in a mighty explosion.