How Fast is That? Obi and his shrinking planet

[Vance]

So according to Brian's admittedly approximate calculations, the planet Utapau visibly shrank by 4 to 5 % in the rear view of Obi's fighter. So is there anyway we can estimate the speed of Obi's fighter, assuming the planet is at least 9,000 kilometres wide (Earth like gravity)?

[youtube]https://www.youtube.com/watch?v=c3rfO9WbpaQ[/youtube]

[Elheru Aran]

I'm not 100% sure of this but I think you can only get a rough estimate from one point of view. To get a better idea you need two points of view to compare from.

Alternatively, now that I'm thinking of it a little bit more. I'm not a math guy by any means, but this is the rough calc, I think...

--Assume Utaupau is approximately Earth-size.

--Approximate a size for whatever surrounds Obi-wan (cockpit, fighter, whatever).

--Measure the span of the time in which you see the planet in the rear view against anything scalable.

--Measure the amount of shrinkage you see in said time.

--Figure out how far you would be from the planet for it to be X size, ditto Y size. You can probably find the calcs for these online somewhere. Probably involves arcs and whatnot.

--Subtract Y from X, and you have the distance you covered in the timespan you find.