Uploaded March 2011 | Updated September 2026, 3 weeks ago
*** This version of the video does not show the horizons rotating: please view youtube.com/watch?v=USkkqB7fFyI instead! ***
Journey of an observer falling inside a(n ideal) Kerr black hole and emerging in a parallel universe. (The black hole has a mass of roughly one million solar masses (Schwarzschild radius = 10 light seconds) and an angular momentum at 80% of maximality (a/M=0.8). The observer has an energy of 1.2 times its mass and zero angular momentum along the black hole's axis.)
In the video, a blue sphere is placed outside the black hole at some distance, a purple sphere is placed in negative space (i.e., beyond the singularity cut), and the outer and inner horizons are various shades of red and green. All spheres are checkered in an identical way, with twenty-four longitudinal stripes and twelve latitudinal (or polar) stripes, consistent with the black hole's axis. The ring singularity itself is not visible as such, but appears as the edge rim of the purple region. Please refer the "combined view version" of this video ( youtube.com/watch?v=cGwY8W3skkY ) for more details on the journey, including a Penrose diagram.
Note: this is a mathematical abstraction: while the parameters (mass and angular momentum) for this black hole are typical for certain real black holes (namely those found in galactic nuclei), physical black holes are not thought to possess any "white hole" component, at least in the past region: so a physical black hole would appear, well, black, and there wouldn't be much of interest to see (and what happens beyond the inner horizon in a physical black hole is pretty much unknown).
Note 2: in this video, the checkered spheres used to visualize the various surfaces do not rotate with the black hole: this is arguably an error for the horizons (although it is unrealistic anyway to place a grid on the horizons, it is even more unrealistic for this grid not to rotate with the black hole). The outer horizons (red spheres) should rotate at one revolution per 126 seconds, and the inner horizons (green spheres) at one revolution at one revolution per 31 seconds.
*** This version of the video does not show the horizons rotating: please view youtube.com/watch?v=USkkqB7fFyI instead! ***
Journey of an observer falling inside a(n ideal) Kerr black hole and emerging in a parallel universe. (The black hole has a mass of roughly one million solar masses (Schwarzschild radius = 10 light seconds) and an angular momentum at 80% of maximality (a/M=0.8). The observer has an energy of 1.2 times its mass and zero angular momentum along the black hole's axis.)
In the video, a blue sphere is placed outside the black hole at some distance, a purple sphere is placed in negative space (i.e., beyond the singularity cut), and the outer and inner horizons are various shades of red and green. All spheres are checkered in an identical way, with twenty-four longitudinal stripes and twelve latitudinal (or polar) stripes, consistent with the black hole's axis. The ring singularity itself is not visible as such, but appears as the edge rim of the purple region. Please refer the "combined view version" of this video ( youtube.com/watch?v=cGwY8W3skkY ) for more details on the journey, including a Penrose diagram.
Note: this is a mathematical abstraction: while the parameters (mass and angular momentum) for this black hole are typical for certain real black holes (namely those found in galactic nuclei), physical black holes are not thought to possess any "white hole" component, at least in the past region: so a physical black hole would appear, well, black, and there wouldn't be much of interest to see (and what happens beyond the inner horizon in a physical black hole is pretty much unknown).
Note 2: in this video, the checkered spheres used to visualize the various surfaces do not rotate with the black hole: this is arguably an error for the horizons (although it is unrealistic anyway to place a grid on the horizons, it is even more unrealistic for this grid not to rotate with the black hole). The outer horizons (red spheres) should rotate at one revolution per 126 seconds, and the inner horizons (green spheres) at one revolution at one revolution per 31 seconds.
