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Fast Oohplah 17/02/01(Wed)17:28 No. 16447 ID: 4318e8

File 148596651718.png - (53.70KB , 506x200 , Audacity_Logo_With_Name.png )

Hey /sci/, how fast would an object need to travel in a circle to look like one solid ring or object. Like if a red ball span so fast it just looked like a solid red ring, not moving at all. How fast is that?

>pic unrelated

Anonymous 17/02/01(Wed)21:19 No. 16448 ID: 8b2816

It depends on the detector that is doing the looking and the specific physical medium that is being used to "look".
Compared to a ring that is not moving, an object that's orbiting tremendously fast must be under a lot of acceleration, and should therefore be producing heat and some IR radiation.

Fogel Fry 17/02/01(Wed)23:23 No. 16449 ID: 6d05e5

Just for strictly non-serious reasons: How fast needs the red ball to travel to dupe the human eye and what would this do to the material the ball is made of?

Coming to that: What material needs the red ball to be made of?

Anonymous 17/02/02(Thu)00:40 No. 16450 ID: 8b2816

It depends on the sort of light that shines on the object. For example, strobe lights are used to visually inspect propellers as they spin in water. If you can time a light to shine very briefly at the same frequency as the object orbits, it will appear to be at a standstill in it regular, non-ring-like form.

Assuming a constant light source, such as the sun, and that the observer is not moving their eyes (because fast-moving objects are visible during saccadic motion), an orbit of a few centimeters in radius would appear as a solid ring rather easily. I would guess at less than 200 Hz (<12 kRPM). Roughly speaking, the larger the radius, the faster it must spin; more specifically, the tangential velocity must stay the same. Additionally, if the orbit is looked at from the side, the object will appear to move slower when it's on the far side of the orbit, so it will need to move even faster than if the orbit is looked at from the axis of rotation. The crucial factor here is how quickly the object traverses the field of view of the observer.

Anonymous 17/03/07(Tue)20:01 No. 16468 ID: 68162d

Fuck idonno

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