Using a satellite called the Total Ozone Mapping Spectrometer (TOMS), NASA researchers have watched as massive clouds of sand, dust, volcanic ash, pollutants and smoke¿particles known as aerosols¿migrate from one continent to another. Now anyone with Web access can do the same by visiting the TOMS aerosol homepage. There, beautiful animations such as the one below show how billows of dust from Africa frequently cross the Atlantic more than 10,000 feet up and blanket the Americas (in particular, the Caribbean). Other movies reveal the traffic in dust and sand from the Middle East to India and China. On August 10 a new QuikTOMS satellite should launch and replace the current instrument, but the shift won't interrupt the steady stream of dusty data.

Image: NASA