Cosmic rays from the solar system. (Astronomy).Dust grains in the outer 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. are the source of some of the cosmic rays cosmic rays, charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (helium nuclei), and lesser amounts of nuclei of carbon, nitrogen, that bombard bom·bard tr.v. bom·bard·ed, bom·bard·ing, bom·bards 1. To attack with bombs, shells, or missiles. 2. To assail persistently, as with requests. See Synonyms at attack, barrage2. 3. Earth, planetary scientists report in the Oct. 30 Geophysical Research Letters Geophysical Research Letters is a publication of the American Geophysical Union. GRL is the organization's only letters journal. Since its introduction in 1974, GRL has published only short research letters, typically 3-5 pages long, which focus on a specific discipline or . The grains are located in the Kuiper belt, which lies within the solar system beyond the orbit of Neptune and consists of comets and other icy objects from the solar system's formation. It's the composition of certain cosmic rays that suggests they originate in the solar system, says Nathan A. Schwadron of the Southwest Research Institute Southwest Research Institute (SwRI), headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development (R&D) organizations in the United States. Founded in 1947 by Thomas Slick, Jr. in San Antonio. These so-called anomalous cosmic rays are energetic charged particles that strike Earth with only about one-hundredth the energy of cosmic rays from the far reaches of our galaxy or beyond. They consist of carbon, silicon, and iron ions. These ions are common in space between stars, but they would have difficulty penetrating the solar system because the solar wind would repel many of them. When objects in the Kuiper belt collide, they generate debris ranging from dust grains a few micrometers in diameter to city-size objects, Schwadron notes. As the grains drift toward the inner solar system, they're buffeted by the solar wind. It shakes carbon, silicon, and iron atoms loose from the grains. The atoms become ionized i·on·ize tr. & intr.v. i·on·ized, i·on·iz·ing, i·on·iz·es To convert or be converted totally or partially into ions. i by the sun's ultraviolet radiation and are then accelerated to enormous energies by the solar wind. Some of the ions ultimately bombard Earth, Schwadron and his colleagues calculate. The discovery that anomalous cosmic rays can be generated from material in the Kuiper belt provides a new tool for gauging the composition and mass of this relic from the solar system's formation, Schwadron says.--R.C. |
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