Is a quasar with a redshift of z = 2 going faster than the speed of light? Why or why not?

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: Using 22 km/s/million light-years for Hubble’s constant, what recessional velocity do we expect to…

A: Given  Hubble's constant , H = 22 km/s/ million light years. Distance of galaxy , d = 600 million…

Q: Estimate the age of the universe for a Hubble constant of (a)50km/s/Mpc, (b) 75km/s/Mpc, and (c) 100…

A: The Hubble time is t = 1/H0 . For each value of Ho, we have: a). t = 6.18 × 10¹⁷ s = 1.96 × 1010 yrs…

Q: Describe a quasar.

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

Q: Imagine that an observed distant galaxy is measured to have a distance of 40 Mpc by a Type Ia…

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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 evidence shows that quasars are ultra-luminous but must be small?

A: Given- What evidence shows that quasars are ultra-luminous but must be small?

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: The evidence leads modern astronomers to conclude that at the cores of active galaxies are…

A: Required : Mass of Supermassive Blackholes in terms of solar mass.

Q: A Type la supernova explodes in a galaxy at a distance of 8.70 x 10' light-years from Earth. If…

A: Given value--- Hubble constant = 68.1 km/s/Mpc . distance of galaxy from Earth = 8.70 × 107 light…

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

A: Mass = E/c2

Q: Observations of quasars have shown us that many are extremely _________, emitting more energy than…

A: Required : Fill in the gaps.

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

A: According to the Hubble's law, the value of the Hubble constant is, v=HdH=vd Here, H is the Hubble's…

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: Fifteen years ago, a quasar was observed that was found to be located 12 billion light years away.…

A: According to the guidelines, I can answer only the 1st question.

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: 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: One interesting feature of quasars is that their energy output can change by great amounts in a…

A: we will someday know everything about our physical universe

Q: What speed should a galaxy move with respect to us so that the sodium line at 589.0 nm is observed…

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Q: Use the distance and velocity data  tofind the rate of expansion as a function of distance.(b) If…

A: a)

Q: What do you mean by quasars?

A: The full form of QUASARS is Quasi Stellar radio sources.

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: 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: what is the difference between an E0 galaxy and an E1 galaxy?

A: An elliptical galaxy has approximately ellipsoidal shape and a smooth, nearly featureless image.…

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.