why is it difficult to measure the Hubble constant?

Q: How would I calculate the age of the universe in billions of years from the Hubble constant (73.48…

A: Everything that exists resides in the universe, including the Earth, planets, stars, space, and…

Q: critical density

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Q: If a quasar has a recessional velocity of 2.7 × 10 5 km/sec and is determined to be 3600 Mpc, what…

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Q: In the laboratory, one of the lines of sodium is emitted at a wavelength of 590.0 nm. In the light…

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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

Q: Describe a quasar.

A: Quasar is an extremely luminous active galactic nucleus. inside quasar there is a supermassive black…

Q: The CMB contains roughly 400 million photons per m³. The energy of each photon depends on its…

A: Write the expression for the Wien displacement law. Here, T is the temperature.

Q: What is the redshift z of a galaxy 193 Mpc away from us?   Note: Assume a value of the Hubble…

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Q: . What is formed when there is a fusion of two deuterium nuclei in big bang nucleosynthesis? a.…

A: Given : 6.fusion of two deuterium nuclei in big bang Nucleosynthesis.

Q: Suppose the Hubble constant were not 22 but 12.1 km/s per million light-years. Then what would the…

A: Write the expression for the volume of the sphere. Write the expression for the mass. Here, ρ is…

Q: If a galaxy is 500 Mly away from us, how fast do we expect it to be moving and in what direction?

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Q: Explain how the temperature of hot gas can be used to find out about the gravitational pull of a…

A: Given: The hot gas temperature which is used to find the gravitational pull To find: The explanation…

Q: What Hubble constant corresponds to an approximate age of the universe of 1010 y? To get an…

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Q: If a galaxy is 9.2 Mpc away from Earth and recedes at 475 km/s, what is H0 (in km/s/Mpc)?

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Q: A galaxy is 30 Mpc away from us and has a recession velocity of 2000 km.s-1 . What is Hubble’s…

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Q: What is the recession speed of a galaxy cluster which is 50Mpc away from Earth? Is the light from…

A: Hubble Law It state that distant galaxies are moving away from our earth with a recession…

Q: What started the clumping of matter in the early universe that eventually became the seeds of…

A: The force that is carried by the field of virtual astronomical particles in the quantum field is…

Q: The CMB contains roughly 400 million photons per m³. The energy of each photon depends on its…

A: The wavelength is 0.0011 m. The energy of a photon is 1.807×10-22 J.

Q: Give the peak wavelengths, λpeak, for each of the following cases. State which portion of the…

A: Given,

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: The CMB contains roughly 400 million photons per m³. The energy of each photon depends on its…

A: Mass = E/c2

Q: In the Benchmark Model, what is the total mass of all the matter within the current Hubble Radius…

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Q: Which of the following is an accurate statement about quasars?

A: ANS: They are abnormally massive, luminous stars at the cores of ancient galaxies.

Q: The hypervelocity star S5HVS1 has a redshifted Hβ line (rest wavelength of 486.135 nm) observed at…

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Q: What is the mechanism for the energy output of quasars?

A: Quasars are high luminosity objects in the galaxy, having very high masses (ranging from millions to…

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: State And Explain Hubbles Law?

A: Hubble’s law states that the distance to a galaxy is proportional to its recession velocity.…

Q: If Hubble’s constant is taken to be 70 km/sec/Mpc, and a quasar is found with a radial velocity of…

A: Given data: The Hubble’s constant is H0=70 km/sec/Mpc. The radial velocity is v=0.95c.

Q: What would be the critical density of matter in the universe if the value of the Hubble constant…

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Q: An object is measured to be at a distance of 20 Megaparsecs away from Earth. Using a currently…

A: According to the Hubble's law, galaxies are moving away from Earth at speeds proportional to their…

Q: How does Hubble’s Constant depend on time? How about distance? (In what sense is it constant?

A: Given: How does Hubble’s Constant depend on time? How about distance? (In what sense is it…

Q: If a galaxy is 18 Mpc from Earth and the Hubble constant is 70 km/s/Mpc, what is the recession…

A: Answer:-  Answer (1)  Given  Distance (d) = 18 Mpc  Hubble constant (Ho) = 70 km/s/Mpc  Velocity of…

Q: What speed should a galaxy move with respect to us so that the sodium line at 58 9.0 nm is observed…

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Q: Give examples of nonbaryonic matter.

A: nonbaryonic matter is the matter found in open space in dark matter. The major classification is…

Q: The red-shift of a galaxy observed by us corresponds to a speed of 50000 km/s. How far is the galaxy…

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Q: What is Hubble constant?

A: Introduction: Hubble constant is the constant of proportionality of the relative velocity of the…

Q: How do we know the whole universe is expanding?

A: Given:-             The expansion of the universe is shows by Hubble by twentieth century was the…

Q: Suppose you have obtained spectra of several galaxies and have measuerd the observed wavelength of…

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Q: A galaxy is observed to recede at speed 140 km/s. If the Hubble constant is 70 km/s/ Mpc, how far is…

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Q: Briefly explain the young Helmholtz theory.

A: Around 19th century Thomas Young and Helmholtz introduced the concept of the Young Helmholtz theory.…

Q: If Hubble’s law can be extrapolated to very large distances, at what distance would the apparent…

A: The equation for the distance at which the apparent recessional speed equals the speed of light is

Q: A certain galaxy is observed to be receding from the Sun at a rate of 8000 km/sec. The distance to…

A: The given values are, v=8000 km/sd=1.4×108 pc=140×106 pc=140 Mpc

Q: The Virgo cluster has a distance of about 17 Mpc from the earth. Using Hubble's law, determine the…

A: Given :  the distance of Virgo cluster, D = 17 Mpc from the earth

Stellar evolution

We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.

Red Shift

It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.