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Firstly, notice that the Frequency of light used to measure time will not remain constant. I wont use this but do take note. Secondly notice that If the object is rigid, then and One end is fixed at x = 0, then the other end in the co-ordinate systems used will be at $\Delta x = \frac{\Delta L}{a(t)}$ So Now light using equation 1 from your question we ...

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Red shift. is a really quick answer. whichever way we look, stuff is moving away from us. and the further away it is the faster it's moving.

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Here's the horizon problem: Look at the sky. Look at one side of the sky. Then look at the other side of the sky. The light from one side has just now reached you, as has the light from the other side. When we look back to the earliest observable moments of the universe, the Cosmic Microwave Background (CMB), we do the same thing. We look at light that was ...

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It is an evidence for the expansion, as seen in supernova studies. Read this paper http://adsabs.harvard.edu/abs/2008ApJ...682..724B We present multiepoch spectra of 13 high-redshift Type Ia supernovae (SNe Ia) drawn from the literature, the ESSENCE and SNLS projects, and our own separate dedicated program on the ESO Very Large Telescope. We use ...

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The concept of the expansion of the universe is hard to get your head around. We describe the universe is infinitely large, and it is expending into itself. So, there is no outside, You can't leave the cosmos. If you could find the edge of the universe and exit through that edge, you would re-enter the universe from the other side. Edges of the universe are ...

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My understanding of the current theory is that galaxies are moving away from each other at an accelerated rate due to dark energy repulsion--creating an expanding universe. However, within galaxies, dark matter keeps the galaxies themselves together--so much so that the outer rim of the galaxy spins at the same rate of the inner rim--meaning there must be ...

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The ultimate fate of the universe (and here I'm taling about things on cosmic scales not what happens to stars and galaxies etc.) depends on the equation of state of the material within it. In cosmology the equation of state is represented by a dimensionless number that is the ratio of the pressure to the (energy) density. i.e. $$w = \frac{P}{\rho}$$ and ...

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This part of Lawrence Krauss' brilliant "A Universe from Nothing" lecture describes the fate of an expanding universe quite well. Long story short, because the expansion of the universe is accelerating, in a hundred billion years or so the rate will exceed the speed of light (this doesn't require objects to move through space faster than light, that's ...

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I believe that the ever expanding universe is the most popular theory as of now. But what is making the universe accelerate? We believe it has to do with Dark Matter and Dark Energy but no conclusive research has been done yet. So in general, we just don't know what will be the end fate of the universe because there is too much unknown about what is ...

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The size of atoms is determined by the strength of the electromagnetic force, the mass of the electron and some other constants like the value of Planck's constant. If the size of atoms was changing it means that one or more of these constants must be changing. The trouble is that these fundamental constants crop up all over the place in physics, and if ...

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In your model, of everything stretching, there would be no way to observe any stretch. We would live in static dimensions as far as we are concerned. It is our observations of the way the stars, galaxies and clusters of galaxies behave that has led to the idea of an expanding universe : Hubble inferred the recession velocity of the objects from their ...

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Your question isn't quite right - not all closed universes are younger than all flat universes, and all open universes are not older than all flat universes. As a reference Universe, pick your favourite flat Universe - the density may be in several components (matter, radiation, $\Lambda$), but it must be exactly critical. Suppose we want an open universe ...

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Let me clear up a few misconceptions. The edge of our observable universe would contain information from the beginning of the universe, since it is a particle horizon. However, the edge of the observable universe is not currently visible to us. What we can currently see only goes as far back as the recombination era, when electrons first joined with nuclei ...

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I am not a cosmologist but I can see a potential flaw in your trying to find an energy "cost" for making the big bang happen. As I am not a cosmologist, though, I can't say categorically that one can't make some consvervation notion meaningful, but from the classical standpoint we have this problem: over cosmological time and distance scales, the notion of ...

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As the comments to the questions state, this is a question on the research state about the generation of the universe, and the first moment is modeled in the Big Bang model. The real beginning point is not yet known even in this model since gravity has not been consistently quantized within the model, only effective theory is used. Nevertheless existing ...

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