The solid line shows the steady growth in the total collecting area of ground-based optical telescopes, including, arbitrarily, the commissioning of a 30-m (CELT?) in 2010, and a 100-m (OWL?) in 2020. The plot is incomplete for older telescopes <= 1.5 m in diameter.

The data are well-fitted by exponential growth with a doubling time of about 8 years (dashed line). This suggests that by approximately 2405, the earth's entire surface will be covered with telescope mirror, which will help a lot with global warming.

This plot was last updated 2002.