Astronomy for the use of schools and academies (1882)
Gillet, J. A. (Joseph Anthony), 1837-1908, Rolfe, W. J. (William James), 1827-1910 · New York : Potter, Ainsworth, & Co. · leaf 66
GH, ofthis cone, whose planemakes with the axis ONan angle less than NOP, is a hyperbola. It will be seen from Fig. 59, in which comparative viewsof the four conic sections are given, that the circle andthe ellipse are closed curves, or curves which return intothemselves. The parabola and the… … 50 ASTRONOMY. and E the earth around which the moon is revolving in thedirection MN. It will be seen that the moon, in moving fromJ/to yV, falls towards the earth a distance equal to mN. Itis kept from falling into the earth by its orbital motion. The fact that abody might be pro-jected forward…
Astronomy
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