When a huge storm erupted on Mars in 2001, scientists were very excited because they had both the Mars Global Surveyor at Mars, and the Hubble Space Telescope in Earth orbit. Both of these observatories gave a close-up view of what was happening on the Martian surface day by day, allowing planetary scientists to learn more about the planet's dust behavior in then-unprecedented detail.
"What we have learned is that this is not a single, continuing storm, but rather a planet-wide series of events that were triggered in and around the Hellas Basin," said Mike Malin of Malin Space Science Systems, Inc., San Diego, lead investigator on the camera, in a 2001 press release. "What began as a local event stimulated separate storms many thousands of kilometers away. We saw the effects propagate very rapidly across the equator — something quite unheard of in previous experience — and move with the southern hemisphere jet stream to the east."
Image: These two Hubble Space Telescope images show Mars before a huge dust storm struck the planet in 2001, and during (at right). Credit: NASA, James Bell (Cornell Univ.), Michael Wolff (Space Science Inst.), and The Hubble Heritage Team (STScI/AURA)