Strange

Clocks are an invention. The units that clocks measure time in (hours, minutes, seconds) are an invention. But they are just a way of measuring time. Time is not an invention. And, when you measure time under different circumstances, you find it changes. Time on the clock changes because the clock is measuring time. Time on the clock does not chnage because the clock has changed. It is because time has changed. Once upon a time, we invented a unit for measuring time called the "day". This unit was based on the rotation of the Earth. Now we use a unit called the "second." This has nothing to do with the rotation of the Earth. No. No. <sigh> Here we go again.

Correct. Also correct. Also correct. (This is some sort of record!) You don't even need a mountain. How about 13 inches: http://www.popsci.com/science/article/2010-09/superaccurate-clocks-prove-your-head-older-your-feet And the classic experiment along these lines was the Pound–Rebka experiment: http://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experiment And, of course, GPS receivers have to take this effect into accounts. So there is not doubt that it is correct.

Yep. That's the link I provied. Light is used to explain it. Time dilation still happens, even with no light present. It won't make any difference. Why is the fact it is an invention be relevant? A clock measures time. If they have the same mass, then the experience the same gravitational force. But that has nothing to do with time dilation. It doesn't matter whether you get it or not. It doesn't matter whether anyone gets it or not. It happens. We can measure it. The light clock example in that video may not be the best way of understanding it (I struggled with it when I first saw it). You obviously don't understand, or you wouldn't reject it. Light in that video is just used as an example to explain things. Time dilation does not depend on the presence of light. It does not depend on whether or not everyone sees the same light or not. It does not depend on light being from the sun or elsewhere.

Although obvious, that is also insightful. It is, ultimately, why so many "prove me wrong" arguments fail.

I have found in the past that adding more detail with Relative just leads you deeper into the quagmire!

Your yellow diagram doesn't make much sense. The presence of light has nothing to do with time dilation. As for: "What in seconds was the result difference in the flight test of the Caesium clock, and how does this compare to the difference in the gravity at the altitude the aeroplane flew at compared to the gravity on the ground?" I'm not sure what you are referring to. Perhaps this: http://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment The closer the electron gets to the proton, the less energy it has. In the same way, when you lift something up it gains potential energy and when you drop it, it loses that energy. For complex reasons (that are way beyond me and therefore beyond you) there is a minmum energy the electron can have in an atom, so there is a minimum distance it can "fall" towards the proton. But the quarks don't touch each other either. (For similar, even more complex reasons.)

Then the pressure would reduce and the temperature would drop until you are left with a ball of iron. Temperature and pressure. I don't think that is true. Because there is a minimum energy that the electron can have. That minimum energy keeps it away from the proton. No No Yes Rock is solid, water is liquid. You can't sink through a solid: that is what "solid" means. If you had wings. You may hvae heard of birds and aeroplanes? No. The satellites would record the same time but different speeds and distances. This is nothing to do with time dilation. It is known as "Galilean Relativity" (after Galileo, who first pointed out that all measurements of movement are relative to who measures them).

Once you start thinking in these terms (light from distant bodies, light being absorbed and re-emitted, etc.) it may be better to take a "classical" view (lightwaves) rather than trying to work out what happens to individual photons.

Just to be clear, what I was referring to was the use of the name "big bang". This should not be used to refer to any initial creation event (if there was one). The big bang model describes the universe we see now. It is a model of a universe expanding and cooling. Speculate away about what might have happened at the start, but there isn't really any good evidence (hence all the different ideas you have encountered).

Space (in this context) is just the distance between things. The universe is described, in the big bang model, as having four dimesions: 3 spatial and one temporal. As you move through the temporal dimension, the spatial dimensions get larger, so the material inside gets less dense. That's about it. (There is, as always, a lot of subtle mathematical detail behind it.)

This takes Dunning-Kruger to a whole new level!

I was talking about two different things. Firstly, "explosion" makes people think that there was some "stuff" densely packed into a corner of the universe that suddenly went bang and spread out through space. That is not what the theory says. Instead, "stuff" was densely spread throughout all of space. Then space expanded so the stuff got less dense and cooled. Eventually it cooled enough to form atoms and then stars and galaxies. (We don't know where the initial "stuff' came from.) This expansion happened at a fairly steady rate. Which is another reason why it was not an explosion. Some people hypothesize that there might have been an initial period of much more rapid expansion of space called "inflation". This is not universally (!) accepted. But if inflation happened, it still wasn't an explosion, because it was space that was expanding, not stuff being thrown out into space.

You could say the same about non-GMO foods. Most of those have had little or no research into their effects. Any GMO crop will be extensively tested before it is allowed to be sold so will probably be safer than most normal fruit or veg.

You mean, make a smaller Earth? Would it hold together? Like the moon, for example? I think that shows the answer is yes. I'm not sure what there is to "get". The mass of the Earth (or the Sun) attracts and holds itself together. In the case of the Earth, it helps that it is solid, which also holds it together. But as the Sun and Jupiter show, a mass of gas can hold itself together equally well.

Centripetal force is only relevant to something moving in a circular path. So, in the case of the moon or the ISS, gravity provides the centripetal force to keep them moving in a curved path. There is not a central void because of the pressure of 6000km of rock pressing down.

I don't know what centripetal force has to do with it. Yes, at the exact centre, there would be no gravity. But move away from there by a fraction of a millimetre, and there would be. All of the mass of the Earth attracts all the rest of the mass of the Earth, holding itself into a sphere. Think of a drop of water: it pulls itself into a sphere in a similar way (not due to gravity in that case, just the forces between atoms). And this shows that your idea that gravity is created at the centre is wrong.

To change momentum requires a force. This doesn't really make much sense. You can't have a free quark attracting another quark. They only exist inside protons and neutrons (and other hadrons). No. There is just a limit to how close an electron can be to the nucleus. It doesn't compare at all. Planets are not subatomic particles and can have any orbit at all, including crashing into the body they are orbiting.

But they are. It is just very, very tiny (because they are small and gravity is weak; it takes the entire mass of the Earth to hold you on the surface). This attraction can be measured: http://en.wikipedia.org/wiki/Cavendish_experiment They are not the "same heavy" at all heights. They are noticeably lighter at the top of a mountain. Attracted to that central point, but not by that central point. If the Earth were a hollow spehere, with nothing at the centre, they would still be attracted to the centre (even though there is nothing there). They are. But again, it is a very small effect. Mount Everest has a mass of about 6x1015kg, the Earth has a mass of about 6x1024kg. So the pull of the Earth will be about 1,000,000,000 times greater than the pull of the mountain. Eventually, yes. (It would oscillate back and forth for a while first but eventually stop at the centre, where the gravity is zero)

They repel each other because they are positively charged. At close range, they attract each other because of the strong nuclear force which overcomes the repulsion. They are attracted because they have opposite charge. There is no easy answer to this question. It comes down to quantum mechanics: there is a minium energy that an electron in an atom can have. This corresponds to it being some distance away from the nucleus.

That sounds quite poetic, but it doesn't make sense (as an English sentence, I mean - nothing to do with physics).

In a spherically symmetrical object (which the sun is, approximately) you can treat gravity as coming from a central point, mathematically. But there is not a little "thing" at the centre which creates gravity. The Sun's gravity is due to the entire mass of hydrogen (and other stuff) it contains (not some particle at the centre). Similarly, the Earth's gravity is due to all the rocks, water, magma, etc. that it contains.

There might be risks with GMO products (although there is no compelling evidence for that) but eating GMO foods is not one of them. This might be of interest: http://www.newscientist.com/article/mg22329800.400-heart-attack-on-a-plate-the-truth-about-saturated-fat.html

The radiation is (mainly) the result of nuclear fusion which heats the plasma. So, yes it is an effect. There is no "central particle". The sun is mainly (more than 90%) hydrogen.

You shouldn't! We have no idea if there ever was such an event. The term "big bang" describes the universe we see around us evolving from an earlier hot, dense state. We don't know what happened before that hot dense state or how it came about.

Yes. No "magnetic bottling". It is held in place by its own gravity. No. EMR is radiation. Plasma is a hot ionised gas. Because it is a hot ionized gas, not molten rock. Sunspots are cooler areas (caused by the magnetic field changing convection).