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bobie
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Matter in U is extimated 1050Kg, what is the radius/volume of the U where this amount of matter is distributed?
Can we get that volume dividing 1050 by this figure?
What is the density of matter: 9.9*10-30*4/100?The present overall density of the Universe is very low, roughly 9.9 × 10−30 grams per cubic centimetre.
Can we get that volume dividing 1050 by this figure?
Is that factor in addition to cosmological redshift or is it already included in z?a(t) is the linear scale of the universe (so a(t) increases as time t increases), then the volume that a given amount of matter occupies is proportional to a(t)3, and thus matter densities scales as 1/a(t)3. Radiation is made of photons, and photon density also scales as 1/a(t)3, but the expansion of the universe also scales the wavelength by another factor of a(t), so radiation energy density scales as 1/a(t)4.
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