The critical density of a universe is around 5×10 kg/m³. Estimate the Hubble constant for this universe.
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A: The objective of the question is to calculate the physical, cosmological horizon size at a given…
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A: ( a ) To find the time t =dv t = 1Mly106ly1Mly9.46×1012km1ly20km/s t = 4.73 x 1017s
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Q: What mechanism can simultaneously solve both the flatness and horizon problems in cosmology?
A: What mechanism can simultaneously solve both the flatness and horizon problems in cosmology
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A: We have to Consider a universe where Big Bang nucleosynthesis produced significantly more 4He than…
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: Explain what is meant by the term cosmological redshift, and contrast it with the Doppler shift that…
A: A Doppler red shift is the expansion of the wavelength and decrease in the frequency when an the…
Q: Assume a flat FRW universe, dominated by radiation throughout its history. Calculate the physical,…
A: The objective of the question is to calculate the physical, cosmological horizon size at a given…
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…
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A: As mass-energy equivalence says that mass and energy are the same, mass can be converted into energy…
Q: Calculate the critical density of a universe with Hubble constant of 89 km-s¹.Mpc¯¹.
A: It is observed that galaxies are moving away from each other and the farther they are faster they…
Q: The critical mass density needed to just halt the expansion of the universe is approximately 10-26…
A: Given that,The critical mass density = 10-26 kg/m3Average mass = 7 eV/c2As we know that,If m is in…
Q: b) The cosmic microwave background dates to a time when the universe was -380,000 years old, or to a…
A: Given: 380000 years ago Tr=3000 Kz=1100
Q: Show that in matter dominated universe density behave as p x (1+z)3 , in radiation dominated as px…
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Q: The mass of the neutrino plays an important role in the universe. Suppose the mass of two neutrinos…
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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,…
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A: Given information: The ratio of free protons to free neutrons is 7.0 It is mentioned that the…
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: Suppose the Hubble constant were not 22 but 53 km/s per million light-years. Then what would the…
A: Given: New Hubble constant, H' = 53 km/s per million light-years
Q: Estimate the critical density of the universe if the Hubble's constant was 100 km/s/Mpc.
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Q: 1. What is the total energy output of a radio galaxy in the local Universe (at z = 0.1) with a flux…
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Q: Calculate the Hubble time for a universe with a Hubble constant of sixty kilometers per second per…
A: Given:Hubble's constant, Ho = 60km/(s Mpc)Asked:Hubble's Time, tH = ?
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: Calculate the temperature of the universe when photons can no longer disassociate deuterons. Use the…
A: Given: The photons can no longer disassociate deuterons.
Q: Use the Friedmann equations to show that the deceleration parameter go and the density parameter N…
A: According to Dark energy and the cosmological constant, the acceleration of the scale factor is…
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: Explain why it only appears that we are at the center of expansion of the universe and why an…
A: Universe is expanding from everywhere and it has no center of expansion. Materials expand from a…
Q: Assume a flat Friedmann-Robertson-Walker universe. Calculate the redshift z at which the temperature…
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Q: If the average density of the Universe is small compared with the critical density, the expansion of…
A: According to Hubble’s law v = HR The expression for R is R=vΔt Thus, v=HvΔtΔt=1H Here, ∆t is the…
Q: Using Ho = = 20.8 km/s/Mly and assuming the expansion rate has been constant, find out how long the…
A: It is observed that the galaxies in our universe are moving away from each other. This expansion of…
Q: a: Assume the universe is flat, and the density parameters of matter and the cosmological constant…
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Q: The CMB decoupled at redshift z≈ 1100, i.e., when its frequency was a factor of z larger. The…
A: The CMB or common microwave background is composed of photons. It is the leftover radiation amount…
Q: Calculate the critical density necessary for a closed universe for two extremes of the Hubble…
A: The critical density necessary for a closed universe for two extremes of the Hubble constant. given,…
Q: What would be the critical density of matter in the universe if the value of the Hubble constant…
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Q: Calculate the Hubble time for a universe with a Hubble constant of 60 km-s-1-Mpc-1.
A: Edwin Hubble observed that the galaxies were moving away from us. He calculated their recession…
Q: Explain how astronomers determined that the universe is expanding.
A: In universe there are millions of stars. These stars are always moving towards Earth or away from…
Q: What is meant by the critical density of the universe? Why is this quantity important to…
A: The critical density is the average density of matter necessary for the Universe's expansion to come…
Q: If the current mass of the universe consists of 75% protons and 25% 4He, what is the current ratio…
A: Given: Universe consists of 75% protons and 25% 4He.
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