Why didn’t the world end when the heavens were even more perfectly aligned in 1997?
Because space is vast, and everything in the heavens is so very far away.
As I discuss in Everyone’s Guide to Atoms, Einstein, and the Universe, there are four forces in nature:strong, electromagnetic, weak and gravity. The strong and weak forces have very short ranges—no larger than the size of an atomic nucleus—less than a trillionth of an inch. The electromagnetic force between large objects is extremely small because their electric charge is extremely close to zero. That leaves gravity. Gravity is intrinsically the weakest of all forces—the gravitational attraction of an electron to a proton is less than a trillionth of a trillionth of a trillionth of their electrical attraction. But, unlike electromagnetism, gravity is attractive for all forms of matter—it relentlessly accumulates. The 10 (raised to the 57) particles in the Sun pull on every one of the 10 (raised to the 51) particles in the Earth, and all those infinitesimal forces, all 10 (raised to the 108) of them, add up to one huge force that holds Earth in orbit. This makes gravity the most powerful and most important force of all. On a cosmic scale, it is gravity that controls the fate of everything.
So how much influence does the force of gravity from celestial bodies have on us? Below is a table of the strength of gravity that various heavenly bodies exert on us stated in g’s, the acceleration of Earth’s gravity at its surface (g = 32 feet per second squared).
Heavenly --------- Its Maximum Gravity
Body ------------ at Earth's Surface in g's
Earth-------------------- 1
Sun --------------------- 0.000,63
Moon ------------------- 0.000,003,8
Jupiter ----------------- 0.000,000,03
Other Planets --------- 0.000,000,02
Milky Way -------------- 0.000,000,000,02
Since Earth’s orbit is slightly elliptical, the Sun’s gravity here varies between 0.000,59 g and 0.000,63 g. Even though Jupiter is 26,000 times more massive than our Moon, it is always at least 1600 times farther away, making its gravity never more than 1% of the Moon’s. Worrying about how the motion of the planets affects us makes no sense at all. The gravity from our immense galaxy, the Milky Way is about 200,000 times less here than the gravity of the Moon. Even though we are drawn by 100 billion stars, they are so far away that their effect is immeasurably small. And, since our distance to the galactic center is quite constant, even its minute force doesn’t change regardless of the orientation of the Earth, Sun, etc. Worrying about where the Sun will rise relative to the galactic center also makes no sense.
On Earth, the gravity of all other celestial bodies is virtually negligible compared to the Sun’s—that’s why Earth orbits the Sun and not anything else. The Moon’s gravity is 100 times less important, and everything else is 100 times less than that. Even the Sun’s gravity is 1600 less here than Earth’s own gravity. From the North Pole to the equator, Earth’s gravity changes by 0.5%, 0.005 on the above table. Changing one’s latitude is 200 times more important than the varying distance to the Sun, 10,000 times more important than the position of the Moon, and a million times more important than the position of all the planets.
No worries Mate.
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