3 ms·
If you go a bit further, you can build surprisingly interesting curves from this math. Try calculating Mars' apparent motion, as observed on earth (i.e., projec
by throwaway_yy2Di 11y ago
If you go a bit further, you can build surprisingly interesting curves from this math. Try calculating Mars' apparent motion, as observed on earth (i.e., projecting the difference of their positions onto a unit sphere). Its path is a loopy [0] curve, and looks like this:
https://imgur.com/a/I43kG https://imgur.com/a/I43kG
Note that you don't need to implement elliptical orbits to see this effect -- circular inclined orbits can exhibit it.
[0] https://en.wikipedia.org/wiki/Apparent_retrograde_motion https://en.wikipedia.org/wiki/Apparent_retrograde_motion
- gunn 11y agoI made an app quite a while ago that lets you explore apparent motions, distances and more in 3D: http://gunn.co.nz/astrotour/?data=tours/retrograde.xml http://gunn.co.nz/astrotour/?data=tours/retrograde.xml (Keep clicking the next arrow at the bottom for a tour). Here's a mars from earth example - http://imgur.com/TeX1yRn http://imgur.com/TeX1yRn
- smcl 11y agoBrian Cox did a simple demonstration of why this was using some stones (link below). It makes a nice bit of sense but it must have messed with early astronomers heads when it was first observed https://www.youtube.com/watch?v=kbynKfNfHk4 https://www.youtube.com/watch?v=kbynKfNfHk4
- dsr_ 11y agoIt certainly did mess with early astronomers. They were also hindered by their supposition that orbits are circles: http://c2.com/cgi/wiki?AddingEpicycles http://c2.com/cgi/wiki?AddingEpicycles