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Chandra Captures X Ray Emissions From Mars
By SPACE.com Staff
posted: 12:35 pm ET
08 November 2002
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NO EMBARGO The Chandra X-ray Observatory has captured the first images of Mars taken at x-ray wavelengths. The Martian radiation is created in a process similar to the way light is created in fluorescent bulbs. X-rays from the Sun collide with oxygen atoms in the thin Martian atmosphere, about 75 miles (120 kilometers) above the surface. The solar photons excite an oxygen electron, bumping it up to a higher energy level. The excited electron quickly returns to its base energy level, emitting another x-ray in the process, which are what Chandra imaged. Fluorescent lights use ultraviolet radiation instead of x-rays. Chandra also detected x-ray emissions in a 4,350-mile (7,000-kilometer) ring around Mars. Researchers suspect that these photons are created in a similar way as solar x-rays excite electrons in oxygen and hydrogen atoms that have escaped Mars' atmosphere. Most x-ray sources are exotic and have temperatures of millions of degrees, such as the centers of galaxies. However, planets, including Earth and Venus, also emit x-rays, and scientists have speculated that Mars can as well. Some believed that dust storms commonly found on the Red Planet could create x-rays, but the new observations have ruled out that theory. As Chandra was imaging Mars, a dust storm that covered half of the planet rotated through the field of view, yet scientists did not detect any change in the x-ray pattern, indicating that the storm did not create radiation. Previous attempts by the Rosat Observatory in 1993 to detect Martian x-rays failed. The Chandra effort, led in part by Konrad Dennerl of the Max Planck Institute, succeeded during a 9-hour observation in July 2001. The findings were published in a recent issue of the European journal Astronomy and Astrophysics. Astronotes
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