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Author: Michael W. Busch
Publisher: Universal-Publishers
ISBN: 1599423227
Category : Science
Languages : en
Pages : 126
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Book Description
Asteroids are diverse and numerous solar system objects, from the large number of objects in the main asteroid belt to the relatively small near-Earth population. Understanding their physical properties is essential to understanding the evolution of the solar system, and asteroid morphology is a complex field in its own right. The histories of individual asteroids, and particularly near-Earth objects, reflect continuous interaction among their shapes, rotation states, and orbits due to the effects of radiation pressure. Radar astronomy has provided detailed information on the orbits, sizes, shapes, rotation states, and composition of many asteroids. To improve the capabilities of asteroid radar observations, I have developed the technique of radar speckle tracking. The echoes from different points on the surface of a radar target interfere with each other, producing a pattern of bright and dark speckles across the surface of the Earth. Using radio astronomy techniques, I track the motion of speckles between several ground stations during a radar experiment to accurately determine the rotation state of the target. Speckle tracking is a powerful tool both to determine the orbital evolution of near-Earth asteroids, particularly potential Earth impactors, and to survey the overall physical properties of the asteroid population. In addition, I have studied applying the techniques of adaptive optics and radio interferometry to asteroid science. These will become more useful with the next generation of asteroid-detecting surveys and the construction of large sub-millimeter interferometers. Interferometry in particular will soon be able to survey the entire asteroid belt.
Author: Michael W. Busch
Publisher: Universal-Publishers
ISBN: 1599423227
Category : Science
Languages : en
Pages : 126
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Book Description
Asteroids are diverse and numerous solar system objects, from the large number of objects in the main asteroid belt to the relatively small near-Earth population. Understanding their physical properties is essential to understanding the evolution of the solar system, and asteroid morphology is a complex field in its own right. The histories of individual asteroids, and particularly near-Earth objects, reflect continuous interaction among their shapes, rotation states, and orbits due to the effects of radiation pressure. Radar astronomy has provided detailed information on the orbits, sizes, shapes, rotation states, and composition of many asteroids. To improve the capabilities of asteroid radar observations, I have developed the technique of radar speckle tracking. The echoes from different points on the surface of a radar target interfere with each other, producing a pattern of bright and dark speckles across the surface of the Earth. Using radio astronomy techniques, I track the motion of speckles between several ground stations during a radar experiment to accurately determine the rotation state of the target. Speckle tracking is a powerful tool both to determine the orbital evolution of near-Earth asteroids, particularly potential Earth impactors, and to survey the overall physical properties of the asteroid population. In addition, I have studied applying the techniques of adaptive optics and radio interferometry to asteroid science. These will become more useful with the next generation of asteroid-detecting surveys and the construction of large sub-millimeter interferometers. Interferometry in particular will soon be able to survey the entire asteroid belt.
Author: International Astronomical Union. Symposium
Publisher: Cambridge University Press
ISBN: 9780521863452
Category : Science
Languages : en
Pages : 538
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Book Description
IAU S236 concentrates on specific techniques of observation and modeling Near Earth Objects (NEOs).
Author: Adam Hodge Greenberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
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Book Description
The purpose of this work is to describe and advance the use of radar data for the determination of asteroid orbits, shapes, and physical characteristics. The data used for these goals include radar images and spectra, as well as radar range and velocity measurements. Herein, I describe improved algorithms for the inversion of asteroid shapes from radar images and spectra, and demonstrate that these algorithms improve shape determination runtime by a factor of two, as well as improve accuracy. I also use radar astrometry, along with optical plane-of-sky observations, to accurately determine asteroid orbits. The results, applied across a sample of 159 near-Earth asteroids, demonstrate that it is possible to constrain the physical characteristics of these objects using dynamics. I also use the size of this sample (currently the largest published) to perform statistical analyses of the results. Finally, I describe radar observations that I took of the near-Earth asteroid 1566 Icarus, and apply the techniques described above to these data. I determine a shape and spin model for this object, and describe several of its heretofore unknown unusual surface scattering properties.
Author: Ishan Sharma
Publisher: Springer
ISBN: 3319404903
Category : Science
Languages : en
Pages : 364
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Book Description
This book develops a general approach that can be systematically refined to investigate the statics and dynamics of deformable solid bodies. These methods are then employed to small bodies in the Solar System. With several space missions underway and more being planned, interest in our immediate neighbourhood is growing. In this spirit, this book investigates various phenomena encountered in planetary science, including disruptions during planetary fly-bys, equilibrium shapes and stability of small rubble bodies, and spin-driven shape changes. The flexible procedure proposed here will help readers gain valuable insights into the mechanics of solar system bodies, while at the same time complementing numerical investigations. The technique itself is built upon the virial method successfully employed by Chandrasekhar (1969) to study the equilibrium shapes of spinning fluid objects. However, here Chandrasekhar’s approach is modified in order to study more complex dynamical situations and include objects of different rheologies, e.g., granular aggregates, or “rubble piles”. The book is largely self-contained, though some basic familiarity with continuum mechanics will be beneficial.
Author: Leon Sinclair
Publisher: Nova Science Publishers
ISBN: 9781634840675
Category : Asteroids
Languages : en
Pages : 0
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Book Description
Scientists classify comets and asteroids that pass within 28 million miles of Earth's orbit as near-Earth objects (NEOs). Asteroids that collide and break into smaller fragments are the source of most NEOs, and the resulting fragments bombard the Earth at the rate of over 100 tons a day. Although the vast majority of NEOs that enter Earth's atmosphere disintegrate before reaching the surface, those larger than 100 meters (328 feet) may survive the descent and cause destruction in and around their impact sites. Furthermore, even smaller objects that disintegrate before reaching Earth's surface can cause significant damage. This book examines NASA's NEO Program and assesses the Agency's progress toward meeting statutory and other Program goals. Specifically, it reviews NASA's allocation and use of resources and plans for the future of the Program.
Author: E. M. Hans
Publisher: Raintree
ISBN: 9780739827420
Category : Juvenile Nonfiction
Languages : en
Pages : 38
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Book Description
This book discusses asteroids, comets, and meteors and their encounters with Earth.
Author: Douglas Taylor Campbell
Publisher:
ISBN:
Category : Asteroids
Languages : en
Pages : 0
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Book Description
An Earth impact with an asteroid has potentially devastating consequences. In order to avoid global destruction, astronomers have been attempting to map out the orbits of all possibly hazardous Near-Earth Asteroids (NEAs) for the past two decades. Although there are a number of astronomers devoted to discovering new NEAs, there are very few who are tracking these discoveries. Therefore many recently identified NEAs are routinely lost. This Trident Scholar Project had two main objectives. The scientific goal of this project focused upon tracking several NEAs in order to determine their orbits. In addition, lightcurves were observed for a subset of these NEAs in order to find their rotational periods and their general shapes. This was done by taking observations of each asteroid for at least one full night and then plotting light intensity versus time. The second objective was to refurbish and upgrade the observatory at the U.S. Naval Academy. Astronomical research at the U.S. Naval Academy hinges on the successful operation of a 20" Cassegrain telescope with a Photometrics 1024x1024 Charge Coupled Device (camera), as well as several computers to control these devices and process the data. As a result of this Trident Scholar Project, the U.S. Naval Academy now boasts a fully functioning, state-of-the-art observatory, including newly acquired and developed software for tracking NEAs and analyzing astronomical observations in general. This Trident Scholar Project added to the body of knowledge of NEAs by determining the orbits of eleven asteroids, as well as the rotational periods and rough shapes of four asteroids. In addition, this Trident Scholar Project will benefit both midshipmen and faculty who wish to either continue tracking NEAs or begin a new field of astronomical research using the now completely established observatory at the U.S. Naval Academy.
Author: Shantanu Naidu
Publisher:
ISBN:
Category :
Languages : en
Pages : 108
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Book Description
In the past 15 years, three previously unrecognized sub-populations of near-Earth asteroids (NEAs) have been discovered. About 15% of NEAs are binaries, at least 10% of NEAs are contact binaries, and dozens of asteroid pairs have been identified. Numerous science questions have arisen about the formation and evolution processes of these systems and about the inter-relationships between these groups. Addressing these questions informs us about a wide range of important solar system processes that shape small bodies and planetesimals. Here I have chosen to focus on providing one of the most complete characterizations of a binary system among all known asteroid binaries, and on studying the spin-orbit interactions in this and 8 additional binary systems. One hypothesis that has not been fully explored is the possibility of chaotic rotation of asteroid satellites and the impact that such a state has on the evolution of the binary systems. I examine this problem as well as the possibility of detecting librational motions in synchronous satellites. Because the Arecibo and Goldstone radar systems enable superb characterizations of binaries and NEAs in general, this dissertation makes abundant use of radar data. Radar observations provide images of asteroids at decameter resolution, and these images can be inverted to determine the 3D shapes of the components, which are essential to properly model the system dynamics. Radar data also enable precise determination of the mutual orbit, which is another crucial ingredient. In the first two chapters of the dissertation, I describe the observations and physical characterizations of asteroid 2000~ET70 and binary asteroid 2000 DP107. The characterization of 2000 DP107 includes size, shape, spin, mass, and density of each component, making this binary one of the best-characterized asteroid binary to date. In the last chapter of the dissertation, I describe a computationally efficient fourth-order numerical integrator that I used to investigate the coupled spin and orbital dynamics of the satellites of NEAs. The speed of the integrator enabled multi-year timescale simulations of 9 well-characterized binary near-Earth asteroids. The numerical simulations illuminate a range of rotational regimes for asteroid satellites and the conditions under which the various regimes prevail. One of the rotational regimes is chaotic, and I find that this rotation state can substantially delay the radiative evolution of binary systems.
Author: Jane P. Gardner
Publisher: Pogo Books
ISBN: 9781645271185
Category : Juvenile Nonfiction
Languages : en
Pages : 0
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Book Description
"In this book, early fluent readers will learn about asteroids, their composition, how they have changed Earth's landscape, and how they could change the future of life on Earth and in space"--
Author: Meg Rosenburg
Publisher:
ISBN: 9781998109845
Category :
Languages : en
Pages : 0
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Book Description
In 2016, NASA took on a new responsibility: defending our planet from devastating impacts by asteroids and comets that approach the Earth, or near-Earth objects. That event, which followed the prominent Chelyabinsk meteor explosion in 2013, reflected a growing interest in, and concern about, the threat of celestial impacts. In ancient times, the solar system's small bodies-asteroids and comets-were sometimes seen as ill omens and warnings from the gods. In modern times, they have come to be seen as the solar system's rubble, leftovers from its formation, but were still largely ignored until the late 20th century. Increasingly, they have been seen by scientists as objects worthy of study, by the general public and the U.S. government as potential threats to be mitigated, and by space advocates as future resources. This book tells the fascinating story of these reinterpretations and NASA's role in them.
