Heavy non-laggy SVG
This demonstrates how to make a SVG map with a lot of elements (stars in the
background)
without any lag (blue planets are rotating smoothly around the sun).
This is done by using a dedicated SVG for the background, in a dedicated file (could
be PHP-generated)
and insert it into this current SVG as a background image.
Planets are links to show that you can click it on-the-fly (for instance, to open
the planet's data).