What was the typical density of the universe, when the microwave background radiation was last scattered (redshift around 1000)? Enter your answer in kilograms per cubic metres.

Q: If the active core of a galaxy contains a black hole of 106 MSun , what will the orbital distance be…

A: Given: The mass of the black hole is 106 MSun. The orbital period is 1 hr.

Q: Explain why the early universe contained only hydrogen but now contains a large variety of different…

A: Hydrogen is the simplest atom in the universe. At the beginning of the universe, when the big bang…

Q: why do you have to know the distance to a galaxy to find its mass?

A: The orbital motion of stars explains the masses of galaxies. The stars in a heavier galaxy exhibit…

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

A:

Q: Assume the observable Universe is charge neutral, and that it contains n nuclei (hydrogen plus…

A:

Q: What does the size difference of the irregularities in the background radiation tell us about the…

A:

Q: Explain how the Hubble constant, H0, can be used to make an estimate for the age of the Universe.…

A: Hubble's Law gives us the conclusion that the universe is always expanding.  It takes very short…

Q: About what percentage of the universe is believed to be composed of normal matter? O 5% O > 22% O…

A: 68% of the matter is dark energy. 27% of the matter is dark matter. Rest less or equal to 5% is…

Q: According to the website of theNational Aeronautics and Space Administration (NASA), the…

A: The temperature (T) of a body or an object is the measure of its degree of hotness or coldness.…

Q: What is the estimated age of the Universe (in years) if the Hubble constant is 70 km/s/Mpc?

A:

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

A:

Q: What does the redshift of the galaxies tell us about their motion with respect to the Earth?

A: The displacement of the spectrum of an astronomical object toward longer wavelength (red) due to the…

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: How would our knowledge about galaxies be altered if we didn't have telescopes? Justify your answer.

A: If we did not have telescopes, it would be impossible to see other galaxies by naked eye, hence we…

Q: How many atomic nuclei (diameter = 1 × 10¬1 cm) would it take to stretch from one end of the known…

A: diameter of atomic nuclei (d) = 10-13 cm = 10-15 m distance of one end of universe to its other end…

Q: Assume the average density of the universe is 0.1 of the critical density needed for closure. What…

A:

Q: What is a super force?

A: Super force is defined as a single force of which electromagnetism, the weak force, the strong…

Q: What is formation and motion of galaxies?

A: Formation of galaxies:           Galaxies are collections of stars, gas, dust and dark matter held…

Q: How long ago was that galaxy right next door to our own Galaxy if it has always been receding at its…

A: The distance is 235 million light-years. The velocity is 4817.5 km/s.

Q: What is the estimated age of the Universe (in years) if the Hubble constant is 80 km/s/Mpc?

A: Hubble constant (H) = 80 kms-MpcUsing , 1 Pc = 3.08×1016 m= 80×1000 ms×106×3.08×1016 m = 2.59×10-18…

Q: Was the Big Bang an explosion? Explain your answer.

A: the Big Bang wasn't an explosion that destroyed things.

Q: In the reading, you were told that there were roughly 10,000 galaxies in the image of the Hubble…

A: Given:  one image of hubble ultra deep field is roughly 10 square arcminutes.  Number of galaxies in…

Q: what evidence is there that galaxies collide and merge?

A: The delicate distribution of matter in the galaxies causes the galaxies to collide and is said as…

Q: Explain how and why Hubble’s observations showed that the universe is expanding?

A: According to Hubble's observation, the light from the galaxies farther away is shifted to longer…

Q: The Universe is approximately 13.8 Billion years old. What is the volume of the visible universe in…

A: Age of universe = 13.8 billion year Distance travel by light in 13.8 billion light year is.…

Q: The background radiation has an average temperature of 2.7 K, using Wien’s Law, the current…

A: Given data:     Current temperature, To=2.7k      Wavelength, λo=1mm      Wavelength, λe=51.1μm…

Q: What is the estimated age of the Universe (in years) if the Hubble constant is 60 km/s/Mpc?

A:

Q: What do you mean by Cosmology?

A: Cosmology is a branch of astronomy that concerns the study of the origin and evolution of the…