(From Science Daily) An international team of astronomers has accurately measured the distance from Earth to a black hole for the first time. Without needing to rely on mathematical models the astronomers came up with a distance of 7800 light years, much closer than had been assumed until now. The researchers achieved this breakthrough by measuring the radio emissions from the black hole and its associated dying star.

Due to the much lower error margin (<6%), astronomers can now gain a better picture of how black holes evolve. Moreover, an exact distance is important for measurements of the black hole´s spin.

Astronomical distances are most easily measured using the so-called trigonometric parallax, in which astronomers make use of the annual shift in the star’s position as a consequence of the Earth’s orbit around the sun (parallax shift). Peter Jonker from SRON Netherlands Institute for Space Research and his colleagues have now applied this method for the first time to a relatively near black hole and its associated star, V404 Cygni, in the Cygnus constellation. The outermost layers of the star are being drawn into the black hole. This gas first of all accumulates in a plasma disc around the black hole before it disappears into it, a process during which a lot of X-rays and radio waves are emitted.

Read more here: Black Hole Found to Be Much Closer to Earth than Previously Thought