File:Black Hole Accretion Disk Visualization.webm

English: This movie shows a complete revolution around a simulated black hole and its accretion disk following a path that is perpendicular to the disk. The black hole’s extreme gravitational field redirects and distorts light coming from different parts of the disk, but exactly what we see depends on our viewing angle. The greatest distortion occurs when viewing the system nearly edgewise.

As our viewpoint rotates around the black hole, we see different parts of the fast-moving gas in the accretion disk moving directly toward us. Due to a phenomenon called "relativistic Doppler beaming," gas in the disk that's moving toward us makes that side of the disk appear brighter, the opposite side darker. This effect disappears when we're directly above or below the disk because, from that angle, none of the gas is moving directly toward us.

When our viewpoint passes beneath the disk, it looks like the gas is moving in the opposite direction. This is no different that viewing a clock from behind, which would make it look like the hands are moving counter-clockwise.

CORRECTION: In earlier versions of the 360-degree movies on this page, these important effects were not apparent. This was due to a minor mistake in orienting the camera relative to the disk. The fact that it was not initially discovered by the NASA scientist who made the movie reflects just how bizarre and counter-intuitive black holes can be!

Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman