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Riding Gravity's Wave. Views of Black Holes

A series of six animations by K. P. Rauch, an astrophysicist at the Department of Astronomy, University of Maryland. Source- a is the spin parameter of a black hole which ranges from 0 for a static (Schwarzschild) black hole up to 1 for an extreme Kerr rotating black hole, it's thought that most black holes reside somewhere around 0.8. The faster the rotation, the more curved space is and the more reduced the event horizon appears, the marginally stable orbit also reduces to the event horizon at a=1. The accretion disk appears arched over the black hole when looking from the equator because the curved space allows you to see behind the black hole. Blog regarding black holes- Blog regarding frame-dragging- Below is a part description, for the full description, go to- Episode I: "The Phantom Monster" (0:10) A stationary observer is located on the spin axis of the hole at r = 10 M. The hole is spun up from a = 0 (Schwarzschild) to a = 0.998 and back to a = 0, and the disk is assumed to respond instantaneously. For this observer the location of the lensed rings is nearly independent of a, whereas the inner disk edge rapidly approaches the horizon as a approaches 1. Episode II: "Into the Fray" (0:58) The viewpoint shifts from the axis (inclination i = 90 deg) to near the disk plane of the a = 0 hole. Once in the plane, the hole is again spun up to a = 0.998 and spun down back to Schwarzschild; Doppler shifts and distortions vary accordingly. Episode III: "Plumbing the Depths" (1:58) The viewpoint slowly descends from r = 10 towards the horizon for an a = 0 hole, as if viewing the camera feed of a tethered probe that is being slowly lowered into the hole. At the photon orbit the probe momentarily stops and pans around to face local zenith (infinity) instead of the hole; just outside the horizon the probe is stopped and reeled in to take a last look back at the lensed disk images. Episode IV: "A One-way Ticket" (2:58) A probe is dropped from a large distance and free-falls into an a = 0.998 hole. The segment begins when the probe reaches r = 6 and displays the fall as recorded by the probe (i.e., constant proper time interval between frames). The view window here is a cut-open cylindrical projection (the left and right edges join and correspond to the view directly *behind* the observer). Episode V: "Pacman Strikes Back" (3:44) The same as IV, only showing the telemetry as received by the distant station, i.e., constant coordinate time interval between frames; as expected, the probe appears to "freeze" at the horizon (r = 1.0632). Watch for the ending Easter egg surprise! :-) Episode VI: "Return to the Dark Side" (4:28) Similar to IV and V, but now the probe slowly spirals into the hole, as if caught in the accretion flow itself. The video is best considered as time-lapse photography taken in equal proper time increments that far exceed the rotational period, which causes the beating effect seen in the hot spots. When the probe passes the inner disk edge at r = 1.237, the multiple lensed images become visible and the universe suddenly looks very confusing! Note that for most of the time, the observer is inside the retrograde photon orbit but outside the prograde photon orbit.
Length: 05:13


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