Visualization of Four-Dimensional Spacetimes

Visualization of the Rigidly Rotating Disk of Dust

disk of dustIn this video, the visualization of the rigidly rotating disk of dust is presented, cf. Sect. 9.3 of the thesis. The visual appearance of the disk as seen by a realistic observer is calculated by using general relativistic ray tracing of the photons emitted by the disk and registered by the observer.

The first part of the video shows the image of the disk of dust as seen by an observer. The observer is looking at the disk from an outside position which lies in almost flat spacetime while the relativistic parameter "mu" is increased. For sufficiently relativistic disks, multiple and distorted images appear. Due to gravitational light bending both the top and the bottom faces are visible simultaneously. An artificial "pie slice" texture is applied both to the top and the bottom side of the disk in order to visualize rotational distortions. In this way, the effects of frame dragging become noticeable.

In the second part of the video, the position of the observer and the parameter mu=3 are fixed. The observer is located on the axis of symmetry and is looking towards the edge of the disk. The sequence starts with a wide angle field of view. Parts of the top side of the disk are visible in the lower part of the picture. An image of the bottom side is found directly above this first image of the top side. Further above, alternating images of the top and the bottom faces follow. Further pictures document increasing zooming in on the original picture. This series reveals self-similarity and a fractal-like structure in parts of the ray-traced images.

This video was shown at Journées Relativistes '99.

Length: 2:17 min