TABLE 836.— LUNAR AND TERRESTRIAL CRATERS (concluded) 



Diameter 

 (ft) 



Wolf Creek 3700 



Eurasian craters : 



Kaalijarv, on Baltic Island of Oesel . 300—360 



Oesel 2 120 



3 100 



4 65 



5 35 



6 (probably double) 120X 175 



At least tbree small craters nearby. . 



Wabar 1 in Rubalkhali of Arabia.. 328 



2 130X180 



At least two smaller craters nearby. 

 Great Siberian craters. About 200 



in number 30 — 175 



Silkhote-Alinsk, U.S.S.R., about 100 



craters < 100 



737 



The 1947 meteorite probably disintegrated high in the air. The 1908 meteorite exploded vio- 

 lently either just before striking the ground or immediately after a ricochet. All others seem to 

 have struck the ground, penetrated a short distance, and then exploded. 



It will be noticed that there is a tendency for several craters to be formed simultaneously as if 

 the meteorites traveled in clusters. 



Only authenticated craters are here listed. Possible or doubtful cases have been omitted. 



TABLE 837.— ALBEDOS 



Object m 



Moon —12.66 



Mercury — 2.20 



Venus — 5.12 



Mars — 1.88 



Jupiter — 2.53 



Saturn + .76 



Uranus + 5.55 



Neptune + 7.80 



Pluto +14.74 



Table compiled by D. L. Harris on the basis of measures by G. Miiller and E. S. King 

 and reduced to the International Photovisual System. Long-period variations of the outer 

 planets have been suspected by W. Becker"'" but are subject to confirmation. 



The albedo, according to Bond, is defined as follows : "Let a sphere .? be exposed to 

 parallel light. Then its albedo is the ratio of the whole amount reflected from S to the 

 whole amount of light incident on it." In the above table, m = the stellar magnitude at 

 mean opposition : <j = magnitude it would have at full phase and unit distance from earth 

 and sun; a — assumed mean semidiameter at unit distance; p = ratio of observed bright- 

 ness at full phase to that of a flat disk of same size and same position, illuminated and 

 viewed normally and reflecting all the incident light according to Lambert's law; q depends 

 on law of variation of light with phase ; albedo = pq. 



Albedo of the earth : 0.39.- m 



** Becker, W., Astron. Nachs.. vol. 277, p. 65. 1949. 

 *» Danjon, Ann. Strasbourg, vol. 3, |)t. 3, |>. 168, 1937. 



SMITHSONIAN PHYSICAL TABLES 



