PASADENA, Calif. — A huge dust storm raging on Mars since last month has spread more than halfway around the Red Planet, NASA said Monday.
The storm is the largest seen since NASA's Mars Global Surveyor went into orbit around the planet in 1997, said Philip Christensen of Arizona State University in Tempe, a principal investigator.
The dust storm is expected to keep growing, perhaps becoming a global storm similar to what was seen during the Mariner 9 and Viking missions of the 1970s, Christensen said.
The storm was first spotted on June 15 when dust began to appear in a region called the Hellas Basin in the southern hemisphere. The storm began to intensify on June 26 and has since grown dramatically.