Astronomy Explained Upon Sir Isaac Newton's Principles: And made easy to those who have not studied mathematicsFerguson, James
Science
Astronomy Explained Upon Sir Isaac Newton's Principles: And made easy to those who have not studied mathematics
Ferguson, James
Astronomy -- Early works to 1800
158. The quick motions of the Moons of Jupiter and Saturn round their
Primaries, demonstrate that these two Planets have stronger attractive
powers than the Earth has. For, the stronger that one body attracts
another, the greater must be the projectile force, and consequently the
quicker must be the motion of that other body, to keep it from falling
to it’s primary or central Planet. Jupiter’s second Moon is 124 thousand
miles farther from Jupiter than our Moon is from us; and yet this second
Moon goes almost eight times round Jupiter whilst our Moon goes only
once round the Earth. What a prodigious attractive power must the Sun
then have, to draw all the Planets and Satellites of the System towards
him; and what an amazing power must it have required to put all these
Planets and Moons into such rapid motions at first! Amazing indeed to
us, because impossible to be effected by the strength of all the living
Creatures in an unlimited number of Worlds, but no ways hard for the
Almighty, whose Planetarium takes in the whole Universe!
[Sidenote: ARCHIMEDES’s Problem for raising the Earth.]
159. The celebrated ARCHIMEDES affirmed he could move the Earth if he
had a place to stand on to manage his machinery[32]. This assertion is
true in Theory, but, upon examination, will be found absolutely
impossible in fact, even though a proper place and materials of
sufficient strength could be had.
The simplest and easiest method of moving a heavy body a little way is
by a lever or crow, where a small weight or power applied to the long
arm will raise a great weight on the short one. But then, the small
weight must move as much quicker than the great weight as the latter is
heavier than the former; and the length of the long arm of the lever to
the length of the short arm must be in the same proportion. Now, suppose
a man pulls or presses the end of the long arm with the force of 200
pound weight, and that the Earth contains in round Numbers
4,000,000,000,000,000,000,000 or 4000 Trillions of cubic feet, each at a
mean rate weighing 100 pound; and that the prop or center of motion of
the lever is 6000 miles from the Earth’s center: in this case, the
length of the lever from the _Fulcrum_ or center of motion to the moving
power or weight ought to be 12,000,000,000,000,000,000,000,000 or 12
Quadrillions of miles; and so many miles must the power move, in order
to raise the Earth but one mile, whence ’tis easy to compute, that if
ARCHIMEDES or the power applied could move as swift as a cannon bullet,
it would take 27,000,000,000,000 or 27 Billions of years to raise the
Earth one inch.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account