Dusty times on Mars. (Astronomy).On July 1, a dust cloud emerged from Mars' Hellas Basin, a crater that ranks as one of the biggest in the solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. . Just 3 days later, the cloud had become 1,800 kilometers wide, roughly one-fourth the Red Planet's diameter. Two years ago, a similar cloud from Hellas Basin grew until it circled the entire planet, blurring Mars into a featureless orange ball (SN: 11/10/01, p. 299). Such planetwide dust storms are rare. Martian dust storms are powered by solar heating solar heating Use of solar radiation to heat water or air in buildings. There are two types: passive and active. Passive heating relies on architectural design; the building's siting, orientation, layout, materials, and construction are utilized to maximize the heating , which whips up the winds that lift dust off the ground. On Aug. 27, Earth and Mars will be closer than they've been in nearly 60,000 years, enabling astronomers to make higher-quality observations of the Red Planet than usual. A few days later, on Aug. 30, Mars will reach its closest approach to the sun. For several weeks before and after that time, the amount of sunlight striking the planet will be about 20 percent more than average. "This means the season for dust storms is just beginning" says James Bell James Bell may refer to:
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