Stardust kicks up mystery
NASA scientists have a new mystery to solve: How did materials formed by fire end up on the outermost reaches of the solar system, where temperatures are the coldest?india Updated: Mar 16, 2006 12:41 IST
NASA scientists have a new mystery to solve: How did materials formed by fire end up on the outermost reaches of the solar system, where temperatures are the coldest? The materials were contained in dust samples captured when the robotic Stardust spacecraft flew past the comet Wild 2 in 2004.
A 100-pound capsule tied to a parachute returned the samples to Earth in January. The samples include minerals such as anorthite, which is made up of calcium, sodium, aluminum and silicate; and diopside, made of calcium magnesium and silicate. Such minerals only form in very high temperatures.
“That’s a big surprise. People thought comets would just be cold stuff that formed out where things are very cold,” said NASA curator Michael Zolensky. “It was kind of a shock to not just find one but several of these, which implies they are pretty common in the comet.”
The discovery raises questions about where the materials in comets form, he added. One theory is that particles from the outer reaches of the solar system slowly move toward the sun, where they are set ablaze and shot back out.
A scientific model once suggested that it might be a natural occurrence, but it wasn’t accepted because materials tend to cluster in zones the farther they are from the sun.
If the model were true, materials would mix more, the NASA scientist said. To determine the origin of the particles, scientists are now studying their isotopic makeup. About 150 scientists worldwide have been studying the dust since it arrived.
During the $212m mission, the Stardust spacecraft looped around the sun three times to capture the interstellar and comet dust. The comet dust was captured in a silicone-based material.