Astronomy Picture of the Day, one of the very best sites on the Web, is celebrating its 15th anniversary today. My heartfelt thanks go to its devoted authors and editors, Robert Nemiroff and Jerry Bonnell--and to NASA for hosting the site.
APOD’s diversity is remarkable. The pictures include straight photographs, highly processed digital images, graphs, and even paintings. They come from professional astronomers, NASA, dedicated amateurs, scientifically inclined artists, and historical archives. The subjects go beyond pure astronomy to include the space program, earth science, and physics. Each picture comes with a short lesson, written by the editors, full of hyperlinks for those who want to learn more.
Although APOD is pitched to the general public, it’s also extremely useful to those of us who teach introductory astronomy, and to any scientist who needs a daily dose of breadth in this era of hyper-specialization.