An illuminating look at the full moon.Just as the full moon makes its monthly debut, the brightness of the lunar surface The lunar surface (or the surface of the moon) differs greatly from that of Earth. Different topography exists and soil composition and properties differ. Environmental factors affect the lunar surface. rises dramatically, far exceeding the luminosity luminosity, in astronomy, the rate at which energy of all types is radiated by an object in all directions. A star's luminosity depends on its size and its temperature, varying as the square of the radius and the fourth power of the absolute surface temperature. of four quarter moons. For more than a century, astronomers Famous astronomers and astrophysicists include: Directory: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
As seen from Earth, sunlight strikes a less-than-full moon at an angle, not head on. In the shadow-hiding scenario, this illumination causes sand-grain-sized dust particles on the lunar surface to cast shadows on neighboring neigh·bor n. 1. One who lives near or next to another. 2. A person, place, or thing adjacent to or located near another. 3. A fellow human. 4. Used as a form of familiar address. v. particles, making the moon look darker from Earth. In contrast, when the moon is full and sunlight strikes head on, the shadows are hidden by the particles that cast them. This would seem to account for the full moon's enhanced brightness. Now, however, astronomers report that an entirely different phenomenon causes the jump in brightness. Simulating the sun by shining laser light on lunar soil Lunar soil is defined as that found on the surface of the Moon. Its properties can differ significantly from those of terrestrial soil. It is essentially devoid of moisture and air, two important components found in soil on Earth. samples, these researchers found that a mechanism called coherent backscattering accounts for the brightening. In backscattering, smaller, soot-grain-sized particles that are stuck to the sand-sized particles on the lunar surface play the featured role. When the moon is full, certain rays reflected by the smaller particles pair up to produce an intensity of light greater than the two rays could produce separately. Thus, the full moon appears brighter than expected, explains Bruce W. Hapke of the University of Pittsburgh. Coherent backscattering may also account for the brightness surge of other planetary plan·e·tar·y adj. 1. Of, relating to, or resembling the physical or orbital characteristics of a planet or the planets. 2. a. moons, Hapke says. If so, the surface character of each moon may differ from that suggested by reflection measurements. Hapke speculates, for example, that Jupiter's moon Europa may have a fluffier layer of surface ice than scientists thought. He and his co-workers, Robert M. Nelson and William D. Smythe of the Jet Propulsion Laboratory “JPL” redirects here. For other uses, see JPL (disambiguation). Jet Propulsion Laboratory (JPL) is a NASA research center located in the cities of Pasadena and La Cañada Flintridge, near Los Angeles, California, USA. in Pasadena, Calif., describe their work in the April 23 SCIENCE. |
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