- Idealism (plato.standford.edu)
This entry discusses philosophical idealism as a movement chiefly in the eighteenth and nineteenth centuries, although anticipated by certain aspects of seventeenth century philosophy and continuing into the twentieth century.
- The Blue Marble (Wikipedia)
The Blue Marble is a photograph of Earth taken on December 7, 1972, from a distance of around 29,400 kilometers (18,300 miles) from the planet’s surface.
