|
|
Origin of the Moon
|
The Moon's heavily cratered far-side
Origin of the Moon refers to any of the various explanations for the formation of the Moon, Earth's natural satellite. The leading theory has been the giant impact hypothesis (GIH). However, research continues on this matter, and there are a number of variations and alternatives. Other proposed scenarios include captured body, fission, formed together (condensation theory), planetesimal collisions (formed from asteroid-like bodies), and collision theories.The standard GIH suggests a Mars-sized body called Theia impacted Earth, creating a large debris ring around the Earth which then formed the system. However, the Moon's oxygen isotopic ratios seem to be essentially identical to Earth's. Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each solar system body. If Theia had been a separate protoplanet, it probably would have had a different oxygen isotopic signature from Earth, as would the ejected mixed material. Also, the Moon's titanium isotope ratio (50Ti/47Ti) appears so close to the Earth's (within 4 ppm), that little if any of the colliding body's mass could likely have been part of the Moon.
^ a b c Cite error: The named reference nasa1 was invoked but never defined (see the help page).
^ Staff (September 7, 2014). "Revisiting the Moon". New York Times. Retrieved September 8, 2014.
^ Theories of Formation for the Moon
^ Wiechert, U.; Halliday, A. N.; Lee, D.-C.; Snyder, G. A.; Taylor, L. A.; Rumble, D. (October 2001). "Oxygen Isotopes and the Moon-Forming Giant Impact". Science (Science (journal)) 294 (12): 345–348. Bibcode:2001Sci...294..345W. doi:10.1126/science.1063037. PMID 11598294. Retrieved 2009-07-05.
^ Scott, Edward R. D. (December 3, 2001). "Oxygen Isotopes Give Clues to the Formation of Planets, Moons, and Asteroids". Planetary Science Research Discoveries (PSRD). Bibcode:2001psrd.reptE..55S. Retrieved 2010-03-19.
^ Nield, Ted (September 2009). "Moonwalk" (PDF). Geological Society of London. p. 8. Retrieved 2010-03-01.
^ Zhang, Junjun; Nicolas Dauphas; Andrew M. Davis; Ingo Leya; Alexei Fedkin (25 March 2012). "The proto-Earth as a significant source of lunar material". Nature Geoscience 5: 251–255. Bibcode:2012NatGe...5..251Z. doi:10.1038/ngeo1429.
|
|
Created By:
System
|
|
|
|
|