Use the Friedmann equations to show that the deceleration parameter go and the density parameter N are related through qo = 2/2 for a universe containing only dust.

Q: Suppose the energy density of the cosmological constant is equal to the present critical density En…

A: Einstein came up with the universal or cosmological constant to balance the calculations in his…

Q: Assume a flat Friedmann-Robertson-Walker universe, and that the density parameters for matter…

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Q: Suppose a hypothetical universe is expanding (at some moment in time) at a rate of H. At this same…

A: Given that for a universe Rate of expanding H = 90 km s-1 Mpc-1 And at this time the density ρ =…

Q: Calculate the critical density of our universe.

A: Our universe is expanding and critical density is defined as the average density of matter that is…

Q: The critical mass density needed to just halt the expansion of the universe is approximately 10-26…

A: Given critical mass density needed to halt the expansion of the universe is ρcrirical = 10-26 kg/m3

Q: Critical density of a universe is found to be 6×10-27 kg/m. Estimate the value of Hubble constant.

A: It was observed that galaxies are moving away from each other and the farther they are faster they…

Q: In the early universe, the formation of л* or лº was through thermal interactions. What is the…

A: As mass-energy equivalence says that mass and energy are the same, mass can be converted into energy…

Q: If a galaxy is 9.3 Mpc away from Earth and recedes at 508 km/s, what is H, (in km/s/Mpc)? 54.62…

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Q: The present number density of electrons in the Universe is the same as that of protons, about 0.2…

A: The present number density of electrons = 0.2m-3. Long before the formation of microwave background,…

Q: The Lyman a line in a galaxy's spectrum was observed to be 208 nm. Calculate the Doppler redshift.

A: When there is relative motion between observer and source the wavelength observed will e shift. When…

Q: The energy density ϵ in radiation is related to its temperature by ϵ=αT4. Compute the temperature…

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Q: Estimate the critical density of the universe if the Hubble's constant was 100 km/s/Mpc.

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Q: Compute a numerical value (in units of protons/m3 ) for the critical density of our Universe. How…

A: The critical density for the Universe is given by, ρ = 3H28πG where H is the Hubble constant and G…

Q: An electron jumps from n=3 to n=2 in a hydrogen atom in a distant galaxy, emitting light. If we…

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Q: Estimate the critical density of the universe if the Hubble's constant was 50 km/s/Mpc.

A: The minimum density that is required to stop the expansion of the universe is defined as the…

Q: According to the version of the Big Bang Theory without a Cosmological Constant (and without Dark…

A: Hubble's Law states that as the universe is expanding in all directions, the receding velocity of an…

Q: Assume a flat Friedmann-Robertson-Walker universe. Calculate the redshift z at which the temperature…

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Q: Consider the following line element, ds^2 = −dt^2 + a^2(t) (dx^2 + dy^2) + b^2(t) dz^2, where a(t)…

A: The objective of the question is to determine whether the given line element obeys the Cosmological…

Q: The rest wavelength of the Hα transition of atomic hydrogen is 656.3 nm (recall that 1 nm=10-9 m).…

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Q: Assume a power law for the scale factor a = Ctn, where C is a constant. (a) For what values of n are…

A: Given data: Scale factor is, a=Ctn. C is a constant.

Q: Assume a flat Friedmann-Robertson-Walker universe, and that the density parameters for matter,…

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Q: If some unknown cause of red shift—such as light becoming “tired” from traveling long distances…

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Q: Consider the following line element, ds^2 = −dt^2 + a^2 (t) (dx^2 + dy^2 ) + b^2 (t) dz^2 , where…

A: Required:  State whether or not this line element obeys the Cosmological Principle, if applied to…