Jacques

How do you conver energy to spacetime ? How do you convert electric charge to spacetime ?

Thanks patcalhoun and h=-16nT If I understand right then a metric is an equation to calculate the distance between 2 locations or more precisely, since it is spacetime, between to events. I see that time is not subject to the scale factor, so time doesn't expand like space. Why since we are suppose to calculate spacetime and time is a dimesion like the others of space ? I have a question that is bugging me since I started studying Relativity, why use ct for the time dimension instead of just t ? Thanks

You give 3 kind of units ...? Can you explain ? Thanks

Thanks Tycho I followed the link and found that they also talk about "space stretching" : I followed the link to the Robertson-Walker metric and found that equation: [math]ds^2 = c^2 dt^2-a(t)^2[dr^2+\bar{r}^2 d\Omega^2][/math] Can you explain it a little bit, in layman term ? Thanks again

Thanks for taking the time to read the web page. About the mole the point is that it is included in the SI even if it's not a unit but is a pure number. I agree with you that it is a very usefull number and that it simplify calculation. Also it is not about converting angstrom to light-years both are unit of space. Have you ever ask yourself What is mass ? Why [math]E=mc^2[/math] ? You don't find it puzzling that you can express all quatity in term of space and time ??? This page don't say stop calculating with your standard equations. They are working fine.

Have you read the link ? Or just the quote ? Take some time For example unit of mass is [math]t^3/s^3[/math] Basically it is saying that all units can be expressed in space and time units

I found this web page and I thinks it make a lot of sense ! I would like to have your comments about it. http://www.blazelabs.com/f-u-suconv.asp Thanks

Thanks for your answer Then am I right by saying that space doesn't expand but space is being created. One unit of lenght does not stretch, but new units of space are added ?

Let say I am observing a galaxy situated 1 billion light-years from me. At that distance the expansion of the universe is apparent. My question: If was able to live long enought and mesure the distance to that same galaxy in 100 million years, will I mesure the same distance 1 billion light-years ? My questioning come from what I readed in a thread that was going something like that : space expansion is not the addition of space unit but the space unit expanding. In an expanding universe, 1 meter (or a billion light-years) still is 1 meter (or a billion light-years) after the universe expand for a time. The meter is just longueur... I am asking the expert there interpretation of the expansion of the universe on distance. Thanks

That's true because of air resistance. Air resistance is proportional to the square (or the cube, can't remember) of the speed. On the moon it won't be true because there is no air.

I have a question who is buging me, maybe I am missing something. Relativity postulate that the speed of light is constant in all references frames. For example an observer in a stationary spaceship (relative to earth) will mesure the speed of light to be c. When the spaceship move close to the speed of light (again relative to earth) the observer will mesure the speed of light to be c also. Time is dilated so space must be contracted to mathematically explain the constancy of the speed of light. Here is my bug: space is contracted in the direction of the motion, but not in the perpendicular direction of the motion. If the ship is travelling in the x direction the contraction is in the x direction and there is no contraction in the y and z direction. Time is dilated no matter the direction. So if I mesure the speed of light in the x direction I still have c, but in the y direction how can I still have c if there is no contraction in the y direction? Thanks in advance to help clear that up.

Space and time keep being created . The expansion of the universe continuously create space and time.

No you don't understand what I am saying. No, matter doesn't repel itself. What I am saying is that space naturally expand. Space doesn't need any original force or energy to expand. Space expand and doesn't stop to expand unless a force going in the opposite direction is applied. I can call it the compressing force by opposition with the universal expansion. I prefer to call it strong gravity. The space expansion happen in 3 dimensions. Any direction you look, space expand (outside our local group of galaxies ). Gravity is also 3 dimensionnal but in the opposite direction. If there is enought of that force going against the expasion in the 3D, you have mass. Space expansion is stopped, but the time expansion doesn't stop. The units of space instead of expanding, are reused again and again in multiples 3D rotations combinations. Yes the inverse square law apply. Yes at some distance the expansion dominate. That distance is called the gravitationnal limit. For the inverse square follow that analogy: Figure the space expansion as a foam of soap bubble with air continuously injected. Figure mass as a vacuum cleaner . The effect of the vacuum cleaner is to destroy the bubble around the hole and the the further away from the hole the smaller the effect. Anyway thanks for your interest but I don't feel that these thaught interest many of you.

North pole or south pole are used in magnetism to name the polarities. Positive or negative are used for electricity. Yes they can. If you have an old monitor (not LCD) you see electrons hiting the pixel of the screen. They traveled from the electrongun at the back of the tube, aimed to each pixel by a modulated magnetic field. The tube is empty of air, an excellent vacum is needed for best control of the electron. My two cents.

http://en.wikipedia.org/wiki/Maxwell_equation When I see that equation, I am amazed that the speed of light is found in the permeability and permittivity of free space! Correct me if i am wrong but,the permeability and permittivity of free space was mesured with capacitor and coil .electric+magnetism => electromagnetism (EM)

I read an article about a motor running why the sun heat In the desert to pump water. The law of thermodynamic apply even with a small temperature difference (but less efficently the pumped water was at 5 C and the air 40 C) Efficency drop to zero when there is no temperature difference.

In your analogy you used a cold object in a bathroom. Star are hot object so it will produce the contrary of a vacum. A hot object create a presure. Fusion goes against gravity.

Do you suppose that gravity act instantly ? Good point ! The weakes is finaly the strongest ! That make no sense to you ? Where do you lose me ? I am temped to answer you that the strong force is nothing else than 'strong' gravity. I will define strong gravity as the negative of the universal expansion. The univerasl expansion bring every thing apart. Gravity goes again that universal expansion. Gravity brings every thing togeter. Mathematically speaking: universal expansion is a positive scalar and gravity a negative scalar. I don't understand what you are refering to ??? In didn't knew that gravity had something to do with that ! I thaught that it was the weak nuclear force governing that scale ...

Like all that is having to do with motion, it's relative. Absolute zero doesn't exist! It's strange how our mind is unconfortable with relative. It's easier to think when we have an absolute to refer to. Absolute is also affected by scale. Like Transdecimal tried to point out: there's always gone to be a question of scale, there always remain some kinetic energy from a lower scale. Classical temperature : 0 kinetic energy from atom (don't look inside the atom). Defenition of absolute zero or 0K: If we put a sensor in a container, the sensor won't record any particle hit. That's stationary relative to the the measuring appartus and at the molecular scale. The theory of Relativity tell us that the only absolute is c. Why not try to use that absolute to do the math on ? Like someone told before on that forum, the math are proven to be good but the theory (QM) is devoid of meaning. The interpretation is not satisfactory. I done calculus (differentiel/integral in french) at university. I know what these maths are about, I passed my exam and I forgot the rules (other are much better in math than me). I am no more able to derive or integrate any equations but the simpliest. Now I am trying to learn more about the physics equations with all ther weirds maths! I find it a priviledge to be able to speak with expert Phd people me a simple seeker.

I don't know yet I didn't ask myself that question. Let me try to continue my reasonning. First we have the basic (natural) state of the universe is expansion. A massless particle like photon does not need any energy to move at the speed of light. It is just carried away with the progession (expansion) of space. The progession of space is 3 dimensional and something to exist must diverge from that progression. The photon diverge from that progression by having 1 negative motion that cancel the progression in one dimension and leaving the other dimension of the progression unaffected. Material things like electron quark etc... Cancel the 3D of the progression. It might have something todo with [math]E=mc^2[/math] s space t time progression=[math]s^3/t^3[/math] mass=[math]t^3/s^3[/math] E=[math]t/s[/math] [math]E=mc^2 => t/s=t^3/s^3 s^2/t^2 [/math] Maybe I should used inverse motion instead of negative motion... So energy is a 1D inverse motion and mass is a 3D inverse motion. OK for now I think I told enought. I don't want to bother you to much with these crazy idea but I am open to continue if there is some interest in what I say. Thanks

Your using the Bhor atomic model and I don't think it's the best model to deal with motion at this scale but I am sure that an atom can't be motionless. Stationary relative to what ? We are on a spinning ball circling the sun, circling the Milkyway nucleus...

Maybe I see a little bit what you mean, the internal motion of charges (quark charge ??) inside particle causing vibration in the magnetic field that propagate to other particle... I think it make sense. Like I said I don't think absolute 0K can be reached.

We learned that gravity is the weakest force in nature. My thinking is that is might be not so weak. Maybe the apparent weakness of gravity is a consequence of the reference frame we use to mesure that force. I know that this idea look strange, but try to follow my reasonning. Usually we fix a reference frame to something material: the table in the laboratory, the earth, the sun, a space ship the center of the Milkyway... and we say this is the zero point from which we do our mesurement. But matter is only a small fraction of our universe, most of it is energy and dark energy, so is it a good idea to fix our reference frame on the material exception ? The universe is expanding in general and contracting on smaller region where there is enought matter, so can't it be that the basic, natural reference frame be an expanding reference frame ?? Relativity enable us to switch from one reference frame to the other and the only constant is c. Wouldn't it be more natural to use c has the 0 speed ? A photon would be stationary in that reference frame. All material objects would have a speed of -1 c. Also we would not need the BigBang to explain the expansion of the universe: the universe is expanding because it is its natural state. Gravity is a force who goes against that natural expansion. What we mesure has gravity is only second order fluctuation of what I called here the "strong gravity" I would like to know if that make some sense to you ? Thanks

The only thing I wanted to point out is that temperature is a mesure of kinetic energy of atoms. I don't know exactly what you mean by , you may be rightt or wrong I am not expert enought to answer you . I also want to point out that to my understanding, it is impossible to have something at 0K.

Temperature is not defined with the internal energy of atoms. Temperature is defined by the kinetic energy of atoms, the motion of atoms. The internal energy of atoms are not part of temperature definition.