Weighing space dust with radar

It is thought that over 1,000 kilograms of so-called interplanetary dust falls to Earth every day. This dust is essentially an untold number of small faint meteors, discarded remnants of asteroids and comets that pass by the Earth. Two ways to study faint meteors are radar and optical observations, each with advantages and limitations. Astronomers have combined specific observations with both methods, and can now use radar to make the kinds of observations that previously only optical telescopes could make.