Orion's trapezium star cluster reveals secrets of black hole formation

At the center of ORION is a 'trapezoidal' star cluster made up of four bright stars. In this small space with a radius of about 1.5 light-years (a light-year is the distance light travels in one year, approximately 9.46 trillion kilometers), the stars illuminate the center of the cluster, particularly the strong ultraviolet rays from the brightest star 'Theta-1 Orionis C' which make the surrounding gases shine. The star cluster, approximately 3 million years old, was denser in its youth, and there is a possibility that a black hole more than 100 solar masses was formed due to past stellar collisions. This black hole explains the rapid movements of the trapezoidal stars and is considered the closest candidate for a black hole, located about 1,500 light-years from Earth.