Astronomy Picture of the Day

Good morning, Rallypoint. Today's Astronomy Picture of the Day (APOD) is titled "Spiral Disk around a Black Hole." This short animated video clip (0:18) is an artist's rendering of the accretion disk orbiting a black hole in spiral galaxy NGC 3147 (130 million light years away in the constellation Draco). Data was gathered by the Hubble Space Telescope. An accretion disk is a structure formed by material in orbital motion around a massive central body (usually a star of some sort). Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum.