Site map . This is one in a series of science images we began presenting in July of 1999. Some are current, some are historic. Each tells a story. If you see a great Science Snapshot, or if you've taken one of your own, e-mail us the url.
Blue areas indicate the ozone hole, red areas indicate higher levels of ozone.
The image at right was taken on Sept. 9, 1999. Ozone is a form of oxygen containing 3 atoms, occurring naturally in the stratosphere , and responsible for filtering out much of the Sun's ultraviolet radiation. E-mail us with general site comments or suggestions. Newsticker for your site Earth . The Edge .