Can anyone tell me why there is a hole in Antarctica? If you view the Earth from directly over the Antarctica, you can see through the north pole region into space. Jupiter does not have a hole in it, nor do the other planets. Is this a bug?
Art G.
Using 2.5.22.1 on a PC
Good question. In fact there is also a hole at the North Pole, though it is much less noticeable. The reason is an historical one, based on the source material used to provide images of the Earth.
In the Earth view, the source material was maps that used the Mercator projection system. This system preserves angles but at the expense of distorting large objects and it is mathematically impossible to map the poles. Rather than filling in the gaps in some way, the decision was made to leave the result as is.
The Solar System view of the Earth was based on NASA maps rendered using Equirectangular projection - a system that has its issues but does not bar mapping of the poles - so the Earth appears complete in this view.
The document http://www.worldwidetelescope.org/docs/worldwidetelescopeprojectionreference.html explains some of the projection issues. The tools used to model the spherical planets based on flat maps attempt to remove some of the distorion that results from mapping a spheric object onto a flat map.
Hi Peter,
Thanks for the answer. Ah, Tradition. I will certainly use your information when I introduce my class to astronomy.