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is caused not by atmospheric drag, but by solid body tidal forces not considered by
Shklovsky. Nonetheless, Sharpless's work stands as the first useful calculation of Phobos's secular acceleration. (His calculations for Deimos, conversely, were deemed "barely significant" due to their high systematic
165:
If the satellite is indeed spiraling inward as deduced from astronomical observation, then there is little alternative to the hypothesis that it is hollow and therefore
Martian made. The big 'if' lies in the astronomical observations; they may well be in error. Since they are based on several
130:, published on the same secular accelerations in 1944 (naming Sharpless as the inspiration), but his work was focused on numerical rather than observational analysis. Sharpless's 1945 paper
58:, graduating in 1926 with an A.B. degree in mathematics. In 1923, he traveled with a group from the college to Yerbanis, Mexico to witness an eclipse of September 10, 1923, and again to
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began studying the cause of the decay in the late 1950s. Working off the hypothesis that the decay was caused by interactions with Mars's thin atmosphere, Shklovsky concluded that
134:
drawing on observations from 1879 to 1941, was the first to compute these accelerations. They provided the first evidence that Phobos's orbit was decaying and would result in
86:
on August 16, 1928; this became a permanent appointment as a junior astronomer on
January 16, 1929. At the beginning of 1930, he was elected a member of the
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independent sets of measurements taken decades apart by different observers with different instruments, systematic errors may have influenced them.
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Sharpless's work was of little interest outside his field for a decade (though it did spark further work in planetary satellites), until
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Singer's speculations were correct; Sharpless's calculations were affected by differences between observations. Additionally, the
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126:(an instrument more suited for high-precision observations), but Sharpless was sooner ready to publish. Another USNO astronomer,
194:, Sharpless retired from the Naval Observatory's Washington, D.C. office on January 1, 1949, and moved to its Florida office at
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In 1929, Harry Edward Burton, head of the
Equatorial Division at the USNO, discovered anomalies in the orbital longitude of
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as little as 6 centimetres (2.4 in) thick - an unambiguously artificial object. Though
Shklovsky later claimed to
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30:(August 2, 1904 – October 28, 1950) was an American astronomer, best known for his 1944 discovery that the orbit of
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Sharpless published in 1946 on photographic observation of comets, work that was conducted in 1943.
624:"Improved estimate of tidal dissipation within Mars from MOLA observations of the shadow of Phobos"
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Miller, J. A. (1925). "The
Swarthmore College eclipse expedition to New Haven, January 24, 1925".
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that the paper was nothing more than a practical joke, it was taken seriously by others including
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Sharpless was born to Ethel Mae Bevan and Albert Wayne
Sharpless on August 2, 1904, in
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Welker, G. W. (1950). "Reports: United States Naval
Observatory. Washington, DC".
368:"Appendix No. 2: Annual Report of the Naval Observatory for the Fiscal Year 1929"
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138:. Sharpless's paper also computed much smaller accelerations for Deimos.
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118:. Sharpless's photographic observations with a 40-inch Ritchey-Chrétien
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Sharpless at the United States Naval
Observatory in a 1930 press photo
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500:"Secular accelerations in the longitudes of the satellites of Mars"
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Sky and Ocean Joined: The U. S. Naval
Observatory 1830–2000
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Secular accelerations in the longitudes of the satellites of Mars
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Sharpless, Bevan P. (1946). "Photographic positions of comets".
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Annual Report of the Naval Observatory for the Fiscal Year 1931
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were inferior to Burton's visual observations with a 26-inch
385:"Forty-third meeting of the American Astronomical Society".
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Annual Report of the Chief of the Bureau of Navigation, 1929
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Singer, F. (February 1960). "More on the Moons of Mars".
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66:. He married Ethel May Gamble on September 10, 1927, in
198:. Long in poor health, he died on October 28, 1950, in
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For two years after graduation, Sharpless worked as an
459:"The secular perturbations of the satellites of Mars"
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94:in the Tonga Islands to make observations of the
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440:Observatory, United States Naval (1 July 1931).
366:Observatory, United States Naval (1 July 1929).
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82:. He received a temporary appointment with the
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622:Bills, Bruce G.; et al. (26 July 2005).
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498:Sharpless, Bevan P. (November 1945).
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231:Descendants of George and Alice Maris
147:Phobos might be a hollow metal object
557:The Internet Encyclopedia of Science
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457:Woolard, Edgar W. (August 1944).
279:Who's Who, The Monthly Supplement
96:solar eclipse of October 21, 1930
64:solar eclipse of January 24, 1925
412:"Travels Far To Observe Eclipse"
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469:(2). Woolard, Edgar W.: 33.
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225:Maris, Ray (11 July 2014).
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343:Cambridge University Press
227:"Bevan Percival Sharpless"
196:Naval Air Station Richmond
751:Swarthmore College alumni
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700:The Astronomical Journal
335:Dick, Steven J. (2003).
28:Bevan Percival Sharpless
285: (6). June 1945.
68:Glenolden, Pennsylvania
183:Later career and death
179:named in their honor.
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60:New Haven, Connecticut
52:Swarthmore High School
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665:Astronomical Journal
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505:Astronomical Journal
463:Astronomical Journal
345:. pp. 408–410.
712:1950AJ.....55..202W
677:1946AJ.....52...76S
640:2005JGRE..110.7004B
518:1945AJ.....51..185S
475:1944AJ.....51...33W
399:1930PA.....38..125.
393:: 128. March 1930.
309:1925PA.....33..341M
281:. (A.N. Marquis Co)
16:American astronomer
56:Swarthmore College
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387:Popular Astronomy
297:Popular Astronomy
177:craters on Phobos
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159:Fred Singer
725:Categories
206:References
155:Carl Sagan
42:Early life
192:emphysema
124:refractor
120:reflector
92:Niuafo'ou
562:7 August
533:7 August
425:7 August
264:7 August
240:7 August
235:RootsWeb
36:decaying
708:Bibcode
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303:: 343.
257:Halcyon
80:actuary
671:: 76.
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116:Deimos
108:Phobos
102:Phobos
32:Phobos
611:: 16.
415:(PDF)
54:then
588:ISBN
564:2014
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112:Mars
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
