File talk:Ergosphere of a rotating black hole.svg

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The original image shows the event horizon as it should be (as a sphere), but when the image is embedded in articles the aspect ratio is not constrained, and the inner event horizon also shows up as an ellipsoid. There seems to be a technical issue with the svg, maybe a reupload can fix this. --Yukterez (talk) 00:36, 30 June 2016 (UTC)[reply]

Hello Yukterez, which article you mean? The ellipsoid form is as it is intended. Compare de:Ereignishorizont #Drehimpuls und elektrische Ladung The circle form has no evidence. I'll mark the "original" image as "no reference". ↔ User: Perhelion 12:28, 30 June 2016 (UTC)[reply]

The ergosphere is an ellipsoid, but the inner horizon should be a sphere. Compare the screenshot: http://666kb.com/i/da9cy0tdejtw7qhg8.gif – on the right you see the image as it is intended to be, while on the left you see the distorted version (maybe a technical error, since on the bottom of each page the mini thumbnail shows the correct aspect ratio). --Yukterez (talk) 18:06, 30 June 2016 (UTC)[reply]

There is a coordinate system in which you can transform the event horizons to ellipsoids, but then the ergospheres are no ellipsoids any more, see http://666kb.com/i/daccpt562mgi69p6j.png – so in a coordinate system where the ergosphere is an ellipsoid, the event horizon is a sphere. --Yukterez (talk) 16:56, 3 July 2016 (UTC)[reply]

Hello Yukterez, can you please more concrete on this, have you any more evidence for this? So we can fix the (most used) "wrong graphic" instead of replacing it with the "old one"… ↔ User: Perhelion 17:02, 9 July 2016 (UTC)[reply]

In your link in the file description de:Ereignishorizont#Drehimpuls und elektrische Ladung you see that the event horizon has constant (the radius of the EH does in contrast to the radius of the ergosphere not depend on the polar angle). It has geometric properties of a rotational ellipsoid, but it is topologically spherical. The surface area nevertheless is that of an ellipsoid, but the radial coordinate is constant (even if the distances one has to travel to the center are not because of the dragging of frames). The old version shows the correct situation in Cartesian coordinates, while the new version seems to be a mix of Boyer-Lindquist and Kerr-Schild coordinates, but then the ergosphere has the wrong shape, correct me if I'm wrong --Yukterez (talk) 04:15, 10 July 2016 (UTC)[reply]

Because all involved persons are German speaking the discussion is now here. ↔ User: Perhelion 09:46, 10 July 2016 (UTC)[reply]
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