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(a) Calculate the approximate age of the universe from the average value of the Hubble constant,
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- I asked the following question and was given the attached solution: Suppose that the universe were full of spherical objects, each of mass m and radius r . If the objects were distributed uniformly throughout the universe, what number density (#/m3) of spherical objects would be required to make the density equal to the critical density of our Universe? Values: m = 4 kg r = 0.0407 m Answer must be in scientific notation and include zero decimal places (1 sig fig --- e.g., 1234 should be written as 1*10^3) I don't follow the work and I got the wrong answer, so please help and show your work as I do not follow along easily thanksarrow_forwardesc a) 10 points) Gravitational Time Dilation. The escape velocity from the surface (radius r) of a star or planet of mass M is given by the formula v = (2GM/r). Use this expression to write the time-dilation fraction, At/t, in terms of the ratio of vesc to the speed of light, c. Hint: This is just a simple exercise in substitution. 5.98 x 1024 kg b) (10 points) Extra Lifetime on the Surface of Earth. The Earth has mass MEarth and radius REarth 6.38 x 10 m. What is the fractional time-dilation (At/t) for someone on the Earth's surface? How much longer (At) is a typical lifetime on the surface of Earth, compared to someone in deep space, far away from Earth? Assume a typical human life span of t = 80 years. Iarrow_forwardName: Hubble Distances Redshift z parameter The relativistic redshift is parametrized by z and given by Δ In terms of the scale factor, 2= X do - de de 1+z= ao a (2) Problem 01. Find the redshift z for a Hydrogen spectral line originally at 656 nm which has been observed at a wavelength of 1.64 μm. Astro 001 Fall 2022 Problem 02. How much smaller was the universe when this light was emitted? U₁ = DHO Using the redshift to measure the velocity, we find D~ (1) 0.1 Hubble's Law Hubble's Law states that the recession velocity of a redshifted galaxy is given by the product of the distance and the Hubble constant. (3) ZC Ho where c = 3 x 108 m/s and Ho = 2.3 x 10-18 s in standard units. The standard measurement of the Hubble constant is Ho = 71 (km/s)/Mpc. Problem 03. What is the distance in Mpc and ly to the galaxy measured in problem 01? 1 pc = 3.26 ly.arrow_forward
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