| Autor: |
Shapiro, Irwin I.1, Chandler, John F.1,2, Murphy, Thomas W.2, Reasenberg, Robert D.1,2 rreasenberg@ucsd.edu |
| Předmět: |
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| Zdroj: |
Journal of Geophysical Research. Planets. Jul2021, Vol. 126 Issue 7, p1-4. 4p. |
| Abstrakt: |
We analyzed high accuracy time delays of laser signals sent from the Earth to the retroreflector arrays on the Moon in conjunction with several other sets of solar‐system astrometric data. Using especially the lunar laser ranging data obtained from the Apache Point Observatory telescope site in New Mexico and the Apollo 11 and Apollo 14 retroreflectors on the Moon, we have set a bound on their relative motion along the connecting great circle of 4 mm/yr over a 14‐year period. Plain Language Summary: Earth's surface is covered with plates, which move with respect to each other at rates from about 15 to 150 mm/year. Almost all scientists who study the Moon believe no such plate motion exists on the lunar surface. Thanks to three sets of retroreflectors left on the Moon by Apollo astronauts and two sets by Soviet spacecraft, we have the capability to accurately measure the round‐trip times of very short laser pulses sent from telescopes on Earth to these retroreflectors. The most precise of such measurements now have an equivalent one‐way distance uncertainty of under 2 mm. We began analysis of these round‐trip times to seek evidence for changes with time in the distances between the first two left there by Apollo astronauts. Their separation along the lunar surface is about 1,248 km. We detected no change in this distance, with an uncertainty of 4 mm/year, from the highest accuracy measurements, made from 2006 to 2020. In the future, with more and more accurate data from all sets of lunar retroreflectors, a similar analysis might, for example, allow determination of the size and other characteristics of a lunar core, as well as possibly permit detection of lunar plate motions. Key Point: Analysis of 14 years of lunar laser ranging data bounds to under 4 mm/year the distance rate between the retro arrays from the Apollo 11 and 14 missions [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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