Is Earth’s closest black hole hiding inside this nebula?
This beautiful photo from the Hubble Legacy Archive offers a striking look at the Trapezium, four closely packed stars found inside the Orion nebula, some 1,500 light-years away. Lurking inside that image might be our nearest black hole neighbor.
The question of which black hole is the closest to Earth is surprisingly tricky to answer. V4641 Sgr might be just 1,600 light-years away, or it might equally possibly be more like 24,000 light-years away. We’ve got a better sense of the location of V404 Cygni, which is just 7,800 light-years away. Considering we’re a little under 30,000 light-years from the supermassive black hole at the center of the Milky Way, those black holes are certainly in the cosmic vicinity, but they’re not exactly super close.
That’s why the Trapezium is so intriguing. Something about the stars’ movements just isn’t right, and the most likely explanation is a hidden black hole. NASA explains this possible secret of the Trapezium:
Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta-1 Orionis C powers the complex star forming region’s entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a recent dynamical study indicates that runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of the Sun. The presence of a black hole within the cluster could explain the observed high velocities of the Trapezium stars. The Orion Nebula’s distance of some 1500 light-years would make it the closest known black hole to planet Earth.
It’s an intriguing thought, but then it’s entirely possible that a black hole — or several black holes, for that matter — are much, much closer to our solar system than 1,500 light-years. That’s rather the trouble with black holes: you don’t generally find them unless you already have a pretty damn good idea where they are in the first place. I believe the astrophysics geniuses over at Red Dwarf once cut to heart of just this very issue.
Via NASA. Credit: Image Data - Hubble Legacy Archive, Processing - Robert Gendler.