Jacques Posted November 28, 2007 Share Posted November 28, 2007 Speculation Postulate 1: space is expanding everywhere (between galaxies as well as inside atoms) Postulate 2: matter is composed of point like particle If every thing scale with time, the density of the universe is constant. Looking back in time, a meter stick seem to contract, but if you go back in time, a meter stick will look the same, everything had contracted. Do you see what I mean ? Thanks in advence for your comments Link to comment Share on other sites More sharing options...
timo Posted November 28, 2007 Share Posted November 28, 2007 No offense, but it looks like a bunch of semi-arbitrary statements to me. SpeculationPostulate 1: space is expanding everywhere (between galaxies as well as inside atoms) What does ""space is expanding" mean? Will the electrons obey the rules of QM and keep their allowed orbits or do the orbits also expand? Postulate 2: matter is composed of point like particle In the sense of "composed of elementary particles"? If every thing scale with time, ... In what relation does "everything scale with time"? Linearly? Quadratic? Cubic? Exponentially? Is that scaling equal for all observables or different for different ones? ...the density of the universe is constant. If the volume occupied by five matter-points is doubled, where did the five new matter-points from? Looking back in time, a meter stick seem to contract, but if you go back in time, a meter stick will look the same, everything had contracted.Do you see what I mean ? No. Try using more precise statements, e.g. define the scaling behaviour for different relevant observables. You seem to be saying "if everything scaled such that every observable was unchanged, then there would be no observable difference". Link to comment Share on other sites More sharing options...
JaKiri Posted November 29, 2007 Share Posted November 29, 2007 In the sense of "composed of elementary particles"? We haven't proved that the electron (say) has any volume. We've set an upper bound on it, though! (Not to say that we've proved that it is a point charge/mass either, but it's debateable which one you feel to be more of a reasonable working assumption) Link to comment Share on other sites More sharing options...
Fred56 Posted November 29, 2007 Share Posted November 29, 2007 space is expanding everywhere (between galaxies as well as inside atoms) The expansion (recession) of galaxies has to overcome any gravitational field (which isn't so hard), and atoms aren't expanding, nor is our planet, nor are we (because an atom is something that is bound by stronger forces, EM and quarks, the planet is gravitationally bound together, and we are in the gravitational 'well')... matter is composed of point like particle You can analyse matter as particles, but also as waves (that interfere like other kinds of waves). Link to comment Share on other sites More sharing options...
Jacques Posted November 29, 2007 Author Share Posted November 29, 2007 atheist What does ""space is expanding" mean? Will the electrons obey the rules of QM and keep their allowed orbits or do the orbits also expand? "space is expanding" like galaxy recession. In the galaxie level, that expansion is not mesurable and even less at the atomic level. The QM rule are the same in the pass as today. Only when you fix a reference frame in time you can see that there was an expansion of space. Expansion of space mean that the space itself expand: 1 meter today is the same as 1 meter yesterday, but if you look today at yesterday meter you will see it smaller. Atheist In the sense of "composed of elementary particles"? Yes elementary particle that are point likeAtheist If the volume occupied by five matter-points is doubled, where did the five new matter-points from? No new "matter-points". Let say that it take 5 billions years of expansion to "double" the volume. 5 billion years ago one of our ancestor sealed a 1 cubic meter box with in it 1 mole of hydrogene. You found that box and you mesured it. It is still 1 cubic meter and as 1 mole of hydrogene in it. But you saw in your scope an alien doing the same thing on an other planet 5 billion light year away and you mesure it only to be half a cubic meter. That is because you are taking a mesurement in the pass with today's instrument. Also, astronomer can see galaxies something like 13 billion light years away: did they observed a change of density ? fred56 The expansion (recession) of galaxies has to overcome any gravitational field (which isn't so hard), and atoms aren't expanding, nor is our planet, nor are we (because an atom is something that is bound by stronger forces, EM and quarks, the planet is gravitationally bound together, and we are in the gravitational 'well')... That make sense but not everybody think the same. Look at the big rip Approximately three months before the end, the Solar system will be gravitationally unbound. In the last minutes, stars and planets will be torn apart, and an instant before the end, atoms will be destroyed. Finally, the scientific principle that the phisic law are the same no matter where you are in the universe can be extented to the 4th dimention time, everywhere and anytime... I know that it look strange that why I put that post in the speculation thread Link to comment Share on other sites More sharing options...
Severian Posted November 29, 2007 Share Posted November 29, 2007 I must admit, I am something of a fan of the notion that the universe is not expanding at all, but that the strengths of the interactions are changing. Since our distance scales are all measured by the strengths of interactions, this would have the identical observable effect as an expansion. Link to comment Share on other sites More sharing options...
MrSandman Posted November 29, 2007 Share Posted November 29, 2007 I really don't believe in the big bang it just seems too radical to be possible, and there is too many questions unanswered about the big bang theory. Link to comment Share on other sites More sharing options...
Mr Skeptic Posted November 29, 2007 Share Posted November 29, 2007 I must admit, I am something of a fan of the notion that the universe is not expanding at all, but that the strengths of the interactions are changing. Since our distance scales are all measured by the strengths of interactions, this would have the identical observable effect as an expansion. I've thought of that too. The speed of light would have to change as well. Overall, the changing constants may be more scary than an expanding universe, but potentially more interesting as well. If we could figure out why constants might change, we might be able to figure out how they came about in the first place. Link to comment Share on other sites More sharing options...
Jacques Posted December 2, 2007 Author Share Posted December 2, 2007 OK I made a mistake in my first postulate. Inside a gravitating system the expansion is not the same, like Fred said. If every thing is scaling then we cannot observe the red shift: a meter expanding at the same rate as the wave lenght of the photon emited cannot give shift in the specter. With that we are back to the bigbang... Unless there are other redshift explaination. That bring me to an other question: At what scale do we stop expanding? From Fred answer I would say at the QM scales. And for big structure I would say galaxys cluster. That bring me to an other question: is dark energy real ? Will the big rip happen ??? Link to comment Share on other sites More sharing options...
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