Duncan Steel is a British scientist currently living in Wellington, New Zealand. He holds visiting positions as a Professor of Astrobiology at the University of Buckingham in England, as a Space Scientist at NASA-Ames Research Center in California, and as an Astronomer at Armagh Observatory in Northern Ireland. Steel is a space science authority who has worked with NASA to assess the threat of comet and asteroid collisions and investigate technologies to avert such impacts. He is also the author of four popular science books on space, and regularly writes for The Guardian and various other newspapers and magazines. He was the discoverer of the main-belt asteroid 9767 Midsomer Norton, plus another eleven minor planets.

Steel has been involved in investigations on small bodies in the solar system using optical telescopes, meteor radar systems, and theoretical techniques to investigate their dynamical evolution. Amongst his scientific achievements have been the first identification of interstellar dust entering the atmosphere, and an influx of comet-derived meteoroids ablating high in the atmosphere that appear to be made of tarry organics.