The idea presented below that the Moon has more surface gravity than the Sun and that this is an inescapable fact is pure hogwash! I am sorry to be so blunt but this idea makes no sense at all. For one thing the Sun is roughly 400 times further away than the Moon and it has to exert some type of influence on the Earth to cause it to orbit the Sun. If the Mass of the Earth is stated as 5.97E+027 grams of weight, then to orbit
the Sun means that at right angles to a straight line vector of force (mass times acceleration) that the Earth would travel if all forces of gravity
from the center of its orbit disappeared, a force would have to be exerted. If one turned off the gravity from the Sun like a light switch you would be left with our planet travelling at 18.5 miles per second in a straight line which would be according to the laws of inertia. Now before the Earth had travelled any further along this course lets calculate the amount of force needed to bend the flight path or vector of motion necessary in order to once again orbit the Sun as it had been. One proof that the Sun must exert a higher surface gravity than the Moon is by calculating this force which is surely greater than the force the Moon exerts on spacecraft that have orbited the Moon.
Another proof is that according to Kepler's third law of planetary motion the period of orbit is proportional to the mean radius of the orbit
of the planet to the 3/2 power. Now if we had the ability to magically reduce the mass of the Sun, our planet would decrease velocity even
though it would be orbiting at the same radius it had been from the Sun. The only difference is that the lesser mass of the Sun would cause the
orbit to be slower. The reason for this is obvious if you consider this question a moment. Since the mass of the Earth had not changed, the mass product of force between the two bodies would lessen with the inverse square value remaining the same. Since there is less mass in this
Sun the orbital velocity of the Earth would have to decrease for the lessened mass product from the sun to bend the Earth's course in the same
orbital shape we have now. A perfect example of this is for two projectiles of equal mass to be propelled at two different velocities. In order to
bend the path of the faster projectile so that it follows a given arc, a lateral force must be applied at right angles to that line of force. Since the
slower projectile has less force ( F = ma ) even though having an equal mass, a lesser force is needed to maintain the same exact given arc that
the faster projectile is moving along.
Now the final crux of my argument is very telling. If the Moon had an equal (let alone greater surface) gravity compared to the Sun, what would we see? Moving toward the Sun makes the orbit faster according to Kepler's third law of planetary motion. If an object moves too
slowly at any orbital radius, we can expect that it will fall into the gravity well of the primary it is orbiting. Mercury is a case in point. It is very
much closer to the Sun than the Earth is and to offset the greater gravitational force of the Sun it must orbit at an average of roughly 27 miles per
second compared to the Earth's 18.5. (the Mercury figure is from memory and might be a little off).
The final nail in the coffin on the idea that the Moon has more surface gravity than the Sun is the orbital velocity of the moon spacecrafts from the center of the Moon. It takes a couple hours to have such vehicles make one trip around the Moon. This is an unequal comparison though. The Moon being so much smaller than the Sun means that we must compensate by determining the drop rate above the moon at a comparative distance above the Sun's surface. Since the radius of the Sun is 432,500 miles across, we will add a little bit and compare the two bodies gravitational performance at 500,000 miles. For the Moon, that would be twice as far away in rough terms as it is from the Earth. This gravity is a very feeble amount but to emphasis the point, if the surface gravity of the Moon was equal to that of the Sun, then an object that was 93,000,000 miles away from the Sun would have to orbit it at 18.5 miles per second. I figured out that a spacecraft orbiting the Moon surface at an altitude of 70 miles and assuming an orbital period of 2 hours (or whatever is correct) would mean that the vehicle was orbiting at roughly
a mile per second or 3600 miles per hour. If this time was wrong and it only took the spacecraft an hour to orbit the Moon, then the velocity would be 7200 miles per hour. Use the geosynchronous orbit formula and solve for the low earth orbit velocity of an object in its orbit. Have we not heard that the orbital velocity of the space shuttle is about 17,000 miles per hour. There can be no question about this. I have shown that the velocity of an orbiting satellite must be directly proportional to the gravitational force of the planet being orbited.
It is not as Mr. Cater states the apparent diameter which must be inversely squared with distance but the mass product. Mr. Cater apparently has not seen fit to consider all the facts. The centrifugal force of the Earth orbit around the Sun is by and large the reason that the
tides effected by the Sun are so much weaker than that of the Moon. The Earth being at the hub of the Moon's orbit does not have any centrifugal force working against the Moon's gravitational force to diminish the Moon's tidal effect.
I had been of a mind to buy Mr. Cater's book but if he espouses things like the Sun and the Moon having equal surface gravities based on their comparative perspective size which is suggested by the fact that the Moon perfectly eclipses the Sun, I don't believe I can justify the expense of his book.
Scott
···
On Sat, 17 Mar 2001 09:33:02 -0300 "Dean De Lucia" [email protected] writes:
Leslee wrote:
I have just finished reading Cater's explanation for high tides, and that tides will be highest during a New Moon. As an astrologer this makes perfect sense to me. The Sun & Moon, when the (moon is at quarter--90 degree), is when the tension between the two is at it's highest, it peaks a minute after an opposition 180, but their energies merge at 0 degrees. I am guessing Cater is saying that when the Sun and Moon are working against each other so to speak, tides will be at their lowest due to less gravitational pull, because the interaction during the times of squares and oppositions is focussed more between the Sun and the Moon, and not the Earth?
Dean Writes:
Leslee,
What specifically interests me about Cater's presentation on the tides is the idea that gravity does not have unlimited penetration through the Earth, in other terms, that gravity is not occasioned by the density of mass. Obviously, there is mass thorughout the Earth's shell and, if gravity does not penetrate, then it cannot be caused by mass.
Anyway, the idea is that if gravity were penetrating and synomamous with the existence of mass, one would be hard-pressed to establish the HET, as the shell of the Earth would have a tendency to collapse inward upon itself. Or else the cavity would hgave to be so small as to practically preclude the existence of any inner sun.
This is why I am interested in studying the nature of tides- the concept of gravity which one accepts either makes or breaks the HET. I really am interested in chatting of the cause and nature of tides and gravity. I know that Scott has some ideas, too, which we should all take a look at.
Here are some of the comments which Cater makes which are of interest:
One of the most extraordinary examples of irrationalism in the history of orthodox physics is the standard explanation of tides. In this case, the discrepancy between reality and orthodox speculation is so colossal it is one of the great enigmas in the history of human thought, that it has not been challenged since the time of Newton. The origin of the difficulty is an obvious flaw in the Newtonian concept of gravitation. It is the idea that gravity effects have unlimited penetration. In other words, there is no attenuation of gravity effects other than that due to the inverse square law as it passes through matter. This is an outrageous violation of the law of conservation of energy.
...
It is now apparent that the idea of unlimited gravity penetration is not valid. This means that the surface gravity effects of the Moon penetrate the Earth for only very limited distances. Therefore, the total acceleration that the surface gravity of the moon imparts to the Earth, as a whole, is very small compared to the acceleration force exerted on an object at the Earth’s surface, such as a body of water facing the moon. This means the water, not being fixed to the Earth, is free to move across the surface by means of the Moon’s gravitational influence. The difference in gravitational accelerations is so great that the acceleration given a body at the surface follows very closely the inverse square law, since the acceleration given the Earth as a whole can be disregarded.
...
The analysis of tides presented above forms the basis for proving that the surface gravity of the Moon is greater than that on the sun. Since the sun and the Moon have the same apparent diameters, viewed from the Earth, tidal effects produced by them are directly proportional to their surface gravities. ... gravitational effects vary inversely as the square of the distance away. Their [ the Sun and the Moon ] apparent diameters are inversely proportional to the distance; therefore, their apparent surface areas also vary inversely as the square of the distance Since the moon is a greater factor in producing tides, the conclusion that the Moon has a greater surface gravity than the Sun is inescapable! To the orthodox mind this produces insurmountable paradoxes.
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