Finding Hazardous Asteroids Using Infrared and Visible Wavelength Telescopes (2019) / Chapter Skim
Currently Skimming:
1 Introduction and Background
1 Introduction and Background
Pages 7-13
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 7... ...
Garcia, 2016, Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact, Atmospheric Chemistry and Physics 16:13185-13212. See also: National Research Council, 2010, Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies, Washington, DC: The National Academies Press.
|
From page 8... ...
Comparable Event Fireball, airburst, shockwave, 25-30 m 80-180 2.6-5.5 million 2 minor damage Local damage comparable to that 50 m 1,500 >~310,000 10 of largest existing thermonuclear weapon Destruction on regional/ national 140 m 20,000 ~24,000 ~500 scale 300-500 m ≥64,000-130,000 3,500-7,200 ≤10,000 Destruction on continental scale Global effects, many millions 1 km 520,000 ~900 80,000 dead Complete extinction of the 10 km 120 million 4 80 million human species NOTE: It is important to note that (1) size is not the only determinant of damage -- other determinants are composition (which may affect how much of the NEO survives its travel through the atmosphere and hits the ground)
|
From page 9... ...
and those capable of causing global effects (objects greater than 1 kilometer in diameter) and has determined that they are not on collision courses with Earth,12 after almost two decades of search, NASA and its partners have catalogued only about one-third of the estimated 24,000 NEOs that are at least 140 meters in diameter.13 11 National Science and Technology Council, 2018, National Near-Earth Object Preparedness Strategy and Action Plan: A Report by the Interagency Working Group for Detecting and Mitigating the Impact of Earth-Bound Near-Earth Objects, Washington, D.C., p.
|
From page 10... ...
Later and more detailed analyses, including an older report by the Naval Research Laboratory, however, found that the impact waves would largely break near the impact itself or on continental shelves, dissipating the impact energy in turbulence and thus not substantially magnifying the hazard. At the present time, impact-generated tsunamis are not considered a serious global hazard, although they may create flooding near the impact site and should be considered in civil defense schemes.14 CHARACTERIZING ASTEROIDS Asteroids emit no visible light of their own; their visible brightness depends on the amount of sunlight reflected/scattered from their surfaces.
|
From page 11... ...
The George E Brown Act, included in NASA's fiscal year 2005 authorization act, amended the National Air and Space Act of 1958 to declare that "the general welfare and security of the United States require that the unique competence of the Administration be directed to detecting, tracking, cataloguing, and characterizing near-Earth asteroids and comets in order to provide warning and mitigation of the potential hazard of such near-Earth objects to Earth."15 Section 321 of the act provides the following specific guidance: The Administrator shall plan, develop, and implement a Near-Earth Object Survey program to detect, track, catalogue, and characterize the physical characteristics of near-Earth objects equal to or greater than 140 meters in diameter in order to assess the threat of such near-Earth objects to the Earth.
|
From page 12... ...
When they are detected, their orbits and physical properties should be determined, and the objects should be monitored insofar as possible. 18 National Science and Technology Council, 2018, National Near-Earth Object Preparedness Strategy and Action Plan: A Report by the Interagency Working Group for Detecting and Mitigating the Impact of Earth-Bound Near-Earth Objects, Washington, D.C., p.
|
From page 13... ...
1.1. "Identify opportunities in existing and planned telescope programs to improve detection and tracking by enhancing the volume and quality of current data streams, including from optical, infrared, and radar facilities.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.