Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 15, 2025
Here then we have another source of the energy present in our earth-moon system; for the moon is hurrying along in its path with a speed of two-thirds of a mile per second, or about twice or three times the speed of a cannon-shot.
As long as the magnitude is declining the minimum has not been reached; it is only when the decline has ceased, and an increase is on the point of setting in, that the minimum can be said to be touched. The earth-moon system contains at any moment a certain store of energy, and to every conceivable condition of the earth-moon system a certain quantity of energy is appropriate.
But here our retrospect has conducted us back to a most eventful crisis, in which the energy was a maximum, and therefore cannot have been immediately preceded by a state in which the energy was greater still; it is therefore impossible for the tidal evolution to have produced this state of things; some other influence must have been in operation at this beginning of the earth-moon system.
Some infinitesimal cause will produce a tendency towards one side, and to that side accordingly the egg will fall. The earth-moon system was similarly in an unstable state, an infinitesimal cause might conceivably decide the fate of the system.
Only it can't be used for Earth-moon communication, because both ends have to be in a vacuum. It could be used to the space platform, but what's the difference? It's a real discovery for which there's no possible use. There's no place to send messages to!" Cochrane's eyes grew bright and hard.
How wide is the contrast between this state of things and the earth-moon system, for the earth does not contain in its rotation one-fifth of the moment of momentum that the moon has in its revolution; in fact, the moon has gradually robbed the earth, which originally possessed 19s. 5d., of which the moon has carried off all but 3s. 4d.
Drop, then, for a moment all thought of tides, and let us bring to our aid the laws of heat, which will disclose certain facts in the ancient history of the earth-moon system perhaps as astounding as those to which the tides have conducted us.
Thus we have shown that the critical condition of dynamical instability must have occurred in the early period of the earth-moon history, if the agents then in operation were those which we now know. The further development of the subject must be postponed until the next lecture.
Starting from that fitting commencement of earth-moon history which the critical epoch affords, we shall now describe the dynamical phenomena as the tidal evolution progressed.
But now mark how truly critical an occurrence this must have been in the history of the earth-moon system, for have I not already explained that it is a necessary condition of the progress of tidal evolution that the energy of the system should be always declining?
Word Of The Day
Others Looking