ISlamabad                  -             The Milky Way galaxy is a staggering 1.9 million light years across, according to a new study, but most of it is made up of dark matter. Astronomers from Durham University calculated the true size of our galaxy by looking at the gravitational pull of smaller neighboring galaxies.

The actual Milky Way disc, made up of stars, black holes, planets moons and other stellar objects is 260,000 light-years across - a fraction of the total galactic size. The rest of the Milky Way is made up of the invisible ‘dark matter halo’ - that is a vast sphere of dark matter enveloping the galactic disc than can’t be directly observed.

Dark matter can only be detected by the impact its gravity has on other objects - it can’t be directly observed, according to astronomers. Astronomers realized the Milky Way is surrounded by a sphere of dark matter after observing that the stars on the outer edge of the disc move faster than they should be moving based on the gravitational influence of detectable matter.