hedgehug's latest activity
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.Bad habit from programming. Me and everyone I worked with have been calling a variable divided by its maximum value normalized.
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.##a(t_{emit})/a(t_{rec})=1/(z+1)\le 1## for ##t_{emit}\le t_0## and ##t_{rec}>t_0## in the expanding universe.
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.I think you just need to have a last word. When I said that there has never been and there never will be other time for anyone, I meant...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.Physical, proper distances are equal after substituting Ly/1101 for NLy.
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Hhedgehug replied to the thread Undergrad Blueshift in case of the Big Crunch scenario.True. It's just a matter of the words used in the definition. Formula remains valid. Your explanations are correct. Just note that...
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Hhedgehug replied to the thread Undergrad Blueshift in case of the Big Crunch scenario.##z## is no longer redshift if ##z+1<1##.
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Hhedgehug replied to the thread Undergrad Blueshift in case of the Big Crunch scenario.If the radiation was emitted at the time of the expansion reversal and observed during the collapse, then ##a_{rec}/a_{emit}<1##. How...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.@Ibix Note that I only really need ##a(t)/a(t_0)=1/(z+1)##, because ##t_0=t_{rec}## and ##t=t_{emit}##.
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Hhttps://en.wikipedia.org/wiki/Scale_factor_(cosmology)#Detail Radiation emitted at the time of the expansion reversal and observed...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.There has never been and there will never be other time for anyone, assuming atheism :) And whenever you live, you simply must have...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.No. I regard the ratio ##a(t)/a(t_0)\le 1## as normalized. That's what must be normalized and that answers my question. Thank you...
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Hhedgehug reacted to Ibix's post in the thread Undergrad Does the scale factor need to be normalized? with
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So if you replace the conventional ##a## with your version that is ##1101a##, the 1101 outside the integral cancels the one inside and... -
Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.Correct. Thank you. Again, for the third time, this cancellation looks exactly like normalization to me. Again it's dividing and...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.Right. Proper distance is ##d(t)=a(t)\chi## where the comoving distance is ##\chi=\int_{0}^{t_0}cdt/a(t)##, so the proper distance...
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Hhedgehug replied to the thread Undergrad Does the scale factor need to be normalized?.Equal.