LUNAR TIDES ARE STILL A MYSTERY TO ME!
I read this in Phil Plait's BAD Astronomy page: Tides, the Earth, the Moon where he says:
Quote:The strength of gravity depends on the distance from the source. The closer you are, the stronger the "pull" you feel. The Moon's gravity acts on the Earth; but the diameter of the Earth is large enough in relation to the distance of the Moon that the side of the Earth nearer the Moon feels the Moon's gravity significantly more strongly than the side of the Earth away from the Moon. If you could stand at the center of the Earth you would feel the Moon's gravity somewhere between the two.
This part is tricky, and is the hardest part of this explanation to understand. A drawing of these forces looks like this:
--> ----> ------->
far center near
side of Earth side
where the arrows represent the force (and direction) of the Moon's gravity on these three points of the Earth. Now, we measure the gravity of the Earth relative to the center of the Earth; everywhere on the Earth, the center is "down". In a sense, we see the center of the Earth as "at rest". It is mathematically correct to then subtract the force of the Moon on the center of the Earth from the force felt on the near and far sides. This is called vector addition. If we do that, our diagram will look like this:
<- X ->
far center near
side of Earth side
(Note that this drawing is not meant to be exact, but just to give a feel for what's happening).
Now we see that in this sense, the Earth is stretched by the difference in the Moon's gravity across the Earth. We call this effect "tides". Tides are a differential force, that is, they result by the difference in the force of gravity between two points.
That is why there are two tidal bulges on the Earth, one on the near side, and one on the far side.
Ha HA,
Vector additions, continued: the Moon's gravity on these three points of the Earth. Now, we measure the gravity of the Earth relative to the center of the Earth; everywhere on the Earth, the center is "down". In a sense, we see the center of the Earth as "at rest". It is mathematically correct to then subtract the force of the Moon on the center of the Earth from the force felt on the near and far sides. This is called vector addition.
DUAL TIDAL BULGE, continued: There is only one way this could be true, and that is if the Earth acts as a shield to the Moon's (or Sun's) gravity, so that it can be subtracted.
I thought about something? you know how we get very sesitive eqiupment to measure gravity and mass. Just thinking about tides low and high, and also thinking about how when they measured items at different times around the world. I dont think I ever saw a report showing the measurement of a weight or a falling object measured everyhour for 30 days?
Here's an article on the anomalous Alais Effect, which sheds some light on how gravity may give different readings during solar eclipse, but does not mention how such readings may be different for the tides. Interesting proposition, that we measure for such slight variations using a specialized gravimeter for that purpose.
Lunar Tides post on BABB which may help understand lunar tides better:
You are the first person that I have seen to point that out as well!!! Its just as bad as my point about gyros which changes the law of force in F=MmG/r^2. That law is specific in relation to the force of two Mass and a certin distance. that they hold a known F just by Mm and r^2, but F can change without M, m, or r^2 changing in values just by spinning m really fast.
My thought on the tides, GET THIS the shell or skin of a planet flexes. Say you have 0 point average. the square area face the Moon has a draw on it making it raise 1' at 3:00pm. as you aproch 6:00pm the drawing froce is not there so it starts to collapse, going under the 0 point level by -1' (that is around 6:00pm). but that harmonic pull on the skin/surface/mantle/core what ever you mathimatical figure into it, will have an oscillation like a bad orbit. It pulls out to the moon 3pm, snaps back by 6pm, swings out again 12 midnight, falls in again by 3am then is pulled back out by 6 am the moon by tidal force. Thats my opinion of it, I never canculated such a passed thought before, but since you brought it back up made me laugh at that all over again from that same questions I asked my learned teachers in the past.
That is in my minds eye, that is why planets with larger moons have a more active mantle layer then those which do not (I think).
If this is so, I wonder if distance stars which have larger planets that warp the diameter of a distant star to seem larger/brighter then they actually are would then give a false reading as to the LIGHT intensity/luminisoty of that star with its so called MASS of the m2 effecting a star. I mean consider the fact that a stars surface could act the same as a tidal liquid of gas. that viewable area could be subject to planetary warping, making that star seem % bigger/smaller over a time period. or even the fact of binary stars tidal effect on each other.
FACT FINDING: IVAN you will have to inclued me on this one for pointing it out if it is true.
Elnino's -spelling may not be right, BUT anyway the energy output of the sun happens every 11 years, which is the period of juptipers orbit verses earth orbit. LOOK FOR the highest yearly outputs of energy coming to the earth, and I would almost bet that Jupiter/%Saturn have been at right angles to earth while the sun was the angle point. if Jupiter has an effect on the surface area of the sun to make it seem larger by a small %, then that means more energy output in the direction of the earth and on the other side of the sun. Also less energy output when Jupiter is inline with the earth or on the Far side of the sun.
If you ever looked at a Sunspot graph, you will notice that they oscilate in the direction of the poles to the diameters of the sun, or vis versa, but the number of osilations are about the same count it would take jupiter earth to make orbit passes in that same time frame.
But what would I know I am a non-learned observer with no formal education.
Food for thought, have fun.
Just something to think about....
By Ivan A. on Wednesday, April 6, 2005 - 10:29 pm:
In the above top post it says:
Quote:
This is still a sticky point with me, that "down" in Earth's gravity allows for us to subtract the Moon's gravity from both sides. There is only one way this could be true, and that is if the Earth acts as a shield to the Moon's (or Sun's) gravity, so that it can be subtracted. Otherwise, the Earth's down pulling is equally canceled all around the globe, so there is no net effect on the Moon's gravity. If the Earth is not a shield, then the vector on the far side should be added rather than subracted.
Curious if this is an issue in anyone else's mind, since it really sticks out in mine!
Ivan
By Ivan A. on Thursday, April 7, 2005 - 11:04 pm:
Quote:
So why would "shielding" work, which is the only way the far side of the Earth could experience a balancing tidal bulge? This may be the most interesting question for time to come, because it may be one more piece of supporting evidence for the Axiomatic Equation: Heat.
If electromagnetic energy, or radiant energy, also measurable as the excitation of atoms as "heat", is inversely proportional to a function of gravity, then it makes sense that a planet's interior heat would in some way "shield" gravity. This means that on the other side of the planet, away from the Moon's direct pull, and same for solar pull, the planet's heat weakens the lunar or solar gravity effect. This may already be evident, per the Axiomatic, in how gravity has a deltaG = ~7.24E-11 Nm^2 kg^-2 per AU, but Earth at one AU is only G = 6.67E-11 N.., which means the planet's interior radiant heat is lowering Earth orbit's gravity "proportional" Newton's G by about 0.6E-11 N... So if the Moon, and Sun, pull directly on the near side of the Earth, causing a high tide there, it conversely pulls inversely on the far side, again causing a high tide. This may be measurable exactly once we better understand how works delta G, and thus the dual bulge of our tides mystery will be solved.
Here are some interesting discussions on Bad Astronomy, with more links, though not necessarily supportive of the above:
Tides and Moon
Allais Effect
What is the cause of tides?
Here's a parting thought: If heat is counter gravity, why do hot air balloons rise?
Think about. If heat excite atoms to cause them to be less mass per volume, then in a higher mass per volume atmosphere, they should rise. Convection works the same way. But is this not another way of saying heat is counter gravity? Think about it!
Once we verify a variable Newton's G, a whole new universe opens to us, one where there are only two forces, opposed, that of gravity and electromagnetic energy, both of which form the atom and all the forces known in our reality. That's what the modified deBroglie-Einstein equation says, that this dual interaction is axiomatic.
Ivan
By Michael on Sunday, April 24, 2005 - 07:01 am:
If you think about when the moon or orbits around as well as the earth spins, at any given time I believe there would be diffrent readings slightly. Yes they are all correct but if they did they could see what/where/when gravity kicks in, and of how much force. It also made me think if they are doing measurements on gravity/time effects. I think they are trying an approach to measuring a mystery like how we ask the same thing about tidal bulges at diffrent points of the moons orbit.
Just as much as you make sense of a tide on one side makes no sense to what is happening on the other side of earth. What does someone call it now "Tidal dialation"?
Just a thought
By Ivan A. on Sunday, April 24, 2005 - 01:45 pm:
Another thought, just popped into my head. I read somewhere (can't remember where, though) that the gravitational effect of eclipse acts on the Earth minutes before the actual light shows the eclipse. This would imply that gravity travels faster than light, but no one seems to be concerned about this. Most physics theory today assumes gravity (as graviton waves) travels at lightspeed, as per Einstein. Could this be wrong? If gravitons are related to light waves, then they should travel at same velocity; but if gravitons either do not exist or are independent of e.m. energy, then gravity may be orders of magnitude faster than light, possibly instantaneous?
Ivan
By Ivan A. on Sunday, April 24, 2005 - 09:19 pm:
What is the cause of tides?
Many interest points preceded this, and no doubt many intersting points will follow.