Meteors

The definitive guide to modern meteor science, destined to be the standard resource for advanced students and researchers.

Blast off on a trip to discover the fascinating world of meteors. In this image-packed book, kids will learn all about these objects hurtling through space—and into our atmosphere. This level 3 reader is written in an easy-to-grasp style to encourage the scientists and explorers of tomorrow!

In any statistical study of characteristics of meteors with data obtained from photographs, corrections must be made for two inherent biasing effects due to the brighter trails left by meteors of greater mass and/or by meteors of greater velocity relative to Earth's atmosphere. In the past, attempts have been made to correct for both biasing effects with a weighting factor inversely proportional to the square of the meteor velocity relative to atmosphere. A new analysis has been made to investigate the magnitude of the weighting factor, specifically for application to photographic meteor data published by Smithsonian Institution Astrophysical Observatory. As a result of this analysis, a revised factor was obtained to operate upon actual counts of photographic meteors within various classes of velocity to provide a correct ratio of counts for all velocities reduced to any given lower mass limit. In the analysis, an expression was derived theoretically for maximum effective exposure on the photographic plate produced by a meteor in terms of the original mass of the particle, its velocity relative to Earth's atmosphere, and the angle of its path to the zenith. The expression for maximum effective exposure was tested and revised by application to 100 test meteors that were believed to have provided approximately uniform effective exposure density. The revised expression for maximum effective exposure was combined with a widely accepted equation for the influx rate of meteors of mass greater than a stated value to obtain approximately the desired weighting factor. The manner of the combination eliminated mass of the meteor particle from the factor. The analysis indicated a large change in value of the exponent of velocity relative to Earth's atmosphere in the weighting factor, namely, from -2 downward at least to -3.85 and possibly as low as -4.22. Application of the new factor should cause a significant reduction of estimates of average meteor velocities relative to the atmosphere. Extensive changes would also be required in estimates of other parameters that might bear a systematic relation to meteor velocities.

In this era of high-tech instruments, meteor observing is the one facet of astr- omy that needs nothing more than your naked eye. Meteors can be easily seen without the aid of cameras, binoculars, or telescopes. Just ? nd a comfortable chair and lie back and watch for the surprises that await high above you. It is a great way to involve the family in science where everyone is active at the same time, not wa- ing to take turns at the eyepiece. The kids especially enjoy the hunt for “shooting stars,” oohing and ahing at each streak of light that crosses the sky. While gazing upwards, it is also a great way to get more familiar with the sky by learning the constellations and seeing if you can see the warrior among the stars of Orion or the scorpion among the stars of Scorpius. Until just recently, one could simply go outside and watch for meteors from his or her yard. Unfortunately, humankind’s fear of the dark and the widespread use of lighting as advertisement have lit the nighttime scene in urban areas so that only the brightest stars are visible. Serious meteor observing under such conditions is nearly impossible as the more numerous faint meteors are now lost in the glare of urban skies. Today, a serious meteor observing session entails organizing an outing to a country site where the stars can be seen in all their glory and meteors of all magnitudes can be viewed.

They range in size from microscopic particles to masses of many tons. The geologic diversity of asteroids and other rocky bodies of the solar system are displayed in the enormous variety of textures and mineralogies observed in meteorites. The composition, chemistry, and mineralogy of primitive meteorites collectively provide evidence for a wide variety of chemical and physical processes. This book synthesizes our current understanding of the early solar system, summarizing information about processes that occurred before its formation. It will be valuable as a textbook for graduate education in planetary science and as a reference for meteoriticists and researchers in allied fields worldwide.

Describes what are meteorites, and where do they come from?

Discusses the solar system bodies that are not one of the nine planets or their moons. This volume describes the discoveries of various asteroids, along with the long centuries of argument over the nature of meteorites and impact craters. It is useful for those interested in understanding the science and history of these bodies.