Earth Mk.I is an experiment with texture mapping in Java3D, which (hopefully) works out fairly well (given that it only took 2 hours to code).
A texture mapped sphere represents the Earth, surrounded by a bluish transparent sphere to represent the atmosphere.
I got bored playing with that, so I added the moon, and a yellowish directional light source to represent the sun.
I have another version of this program kicking around somewhere which includes stars, a visible sun, and better lightsources.
You can download the compiled class files (including necessary textures):
Tor Oera's fantastic site - http://www.oera.net and Tor's 3D Earth tutorial
Fourmilab's Earth View - http://www.fourmilab.ch/earthview/
NASA's Earth from Space site - http://earth.jsc.nasa.gov/
16th August 2001