Recent content by v2kkim

On TV science channel, I heard the actual univ. size is about 20% larger that the visual univ. to us.

In principle you may be right , something reflecting space expansion effect in atomic scale, on which I can just speculate based on my limited knowledge of quantum physics. The basic equation of quantum mechanics is Schrödinger wave equation, and well maybe you can try yourself, because: First...

The explanation by advisor and mentor helped me a lot to understand. On this Axuality's question, I 'd say the answer is yes in infinitely short moment.. i. e. the expansion applies even in subatomic scale, but this expansion does not accumulate as time goes on in short distance. In long...

I can imagine that you move faster than speed of light, like you are at point A and after 1 sec point B (2*c distance) .. etc. which is a purely imagination. Then you will see the Earth event moving backward, on which I am sure.

Another way to look at the expansion effect in small scale is to start with Earth and sun orbit. Th expansion and the gravitation will happen at the same time, though gravitation is much larger. Here, discrete modeling may help, that is say the sun-earth distance increases a little instantly due...

Something is going strange in this dialog. I think the gravitation effect is stronger on the Earth surface and minimum at the center of the earth. Therefore the surface clock is slower than center one.

I agree. If we change the question like bob is moving all the time at the same speed passing the Earth and another far away planet taking a straight course, then we can calculate exactly thanks to S. R. theory.

I remember that people say some black holes have finite size like a disk so it can rotate with angular momentum, but the disk thickness is zero so still zero volume.

For first item, moving 2 systems are equivalent so we can not tell which one is slower, but accelerating system is different, so I think we should not forget about acceleration. If you got confused oversimplifying the fact by leaving accel.. behind then it is your own problem.

One thing is Time Dilatation you referred is a result of math from special relativity equations. Using those equation we can explain one simple but important observation that the speed of light is the same regardless of the observer frame speed. Then you may ask can we derive the special...

Maybe we can explain using semiconductor concept. Semiconductor has a band gap which is the difference between valence band and conduction band, and photons of larger energy than this band gap can be absorbed. In diamond the band gab is larger than visual light I think, but in silicon it is...

From experience we know that the current in a conductor is zero when no external EM field. In this case, if E-field is not zero then there will be a current at the position in a conductor so logically E-field is zero. If there are external EM field then the field will penetrate from the surface...

I see two different point of view on far away galaxy expansion: (1) Space expansion point of view : space is expanding everywhere. (2) Continuing expansion motion of objects : a kind of simple Newton inertia. One common result is Galaxies will expand continuously each other if there is no...

Some people may say I am wrong but I like to post my opinion of the expansion rate. Hopefully it helps us to have a better perspective of our universe. The expansion rate does not accelerating but decreasing in a sense that the expansion rate means the rate of length change for a unit length...

My understanding is that a galaxy does not expand, even possibly contract due to gravitation. However the space expansion is quite universal, so applys to each space in a galaxy. But in a galaxy after each tiny expansion between objects, they adjust their motion due to gravity, and we know in...