Read Books Online, for Free |
Earth to the Moon | Jules Verne | |
REPLY FROM THE OBSERVATORY OF CAMBRIDGE |
Page 2 of 3 |
As to the second question, "What is the exact distance which separates the earth from its satellite?" Answer.-- The moon does not describe a circle round the earth, but rather an ellipse, of which our earth occupies one of the foci; the consequence, therefore, is, that at certain times it approaches nearer to, and at others it recedes farther from, the earth; in astronomical language, it is at one time in apogee, at another in perigee. Now the difference between its greatest and its least distance is too considerable to be left out of consideration. In point of fact, in its apogee the moon is 247,552 miles, and in its perigee, 218,657 miles only distant; a fact which makes a difference of 28,895 miles, or more than one-ninth of the entire distance. The perigee distance, therefore, is that which ought to serve as the basis of all calculations. To the third question. Answer.-- If the shot should preserve continuously its initial velocity of 12,000 yards per second, it would require little more than nine hours to reach its destination; but, inasmuch as that initial velocity will be continually decreasing, it will occupy 300,000 seconds, that is 83hrs. 20m. in reaching the point where the attraction of the earth and moon will be in equilibrio. From this point it will fall into the moon in 50,000 seconds, or 13hrs. 53m. 20sec. It will be desirable, therefore, to discharge it 97hrs. 13m. 20sec. before the arrival of the moon at the point aimed at. Regarding question four, "At what precise moment will the moon present herself in the most favorable position, etc.?" |
Who's On Your Reading List? Read Classic Books Online for Free at Page by Page Books.^{TM} |
Earth to the Moon Jules Verne |
Home | More Books | About Us | Copyright 2004