Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 25, Problem 53Q
To determine
(a)
The deceleration parameter at a redshift of
To determine
(b)
The deceleration parameter at a redshift of
To determine
(c)
An explanation an how the results show that the universe expansion is decelerating at
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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.
At time t=0s, there are No unstable pions. What fraction of pions decay after
travelling a distance of 25 m? Assume the pions travelling at 0.86c and their average
lifetime is 20.0 ns.
Select the correct answer choice:
(a)
85.9%
(b) 91.6%
(c) 99.2%
(d) 89.2%
Consider a cosmological spacetime in which the line element is given by
ds? = a²(t)(-dt + dr² + dy² + dz²),
where a(t) > 0 is the scale factor. Two light rays tangent to l = (1,1,0, 0)
and l = (1,0, 1,0) are received at time t =
u" = (a-'(to), 0, 0, 0). Compute the observed angle between the correspond-
ing images.
to by someone with 4-velocity
Chapter 25 Solutions
Universe: Stars And Galaxies
Ch. 25 - Prob. 1QCh. 25 - Prob. 2QCh. 25 - Prob. 3QCh. 25 - Prob. 4QCh. 25 - Prob. 5QCh. 25 - Prob. 6QCh. 25 - Prob. 7QCh. 25 - Prob. 8QCh. 25 - Prob. 9QCh. 25 - Prob. 10Q
Ch. 25 - Prob. 11QCh. 25 - Prob. 12QCh. 25 - Prob. 13QCh. 25 - Prob. 14QCh. 25 - Prob. 15QCh. 25 - Prob. 16QCh. 25 - Prob. 17QCh. 25 - Prob. 18QCh. 25 - Prob. 19QCh. 25 - Prob. 20QCh. 25 - Prob. 21QCh. 25 - Prob. 22QCh. 25 - Prob. 23QCh. 25 - Prob. 24QCh. 25 - Prob. 25QCh. 25 - Prob. 26QCh. 25 - Prob. 27QCh. 25 - Prob. 28QCh. 25 - Prob. 29QCh. 25 - Prob. 30QCh. 25 - Prob. 31QCh. 25 - Prob. 32QCh. 25 - Prob. 33QCh. 25 - Prob. 34QCh. 25 - Prob. 35QCh. 25 - Prob. 36QCh. 25 - Prob. 37QCh. 25 - Prob. 38QCh. 25 - Prob. 39QCh. 25 - Prob. 40QCh. 25 - Prob. 41QCh. 25 - Prob. 42QCh. 25 - Prob. 43QCh. 25 - Prob. 44QCh. 25 - Prob. 45QCh. 25 - Prob. 46QCh. 25 - Prob. 47QCh. 25 - Prob. 48QCh. 25 - Prob. 49QCh. 25 - Prob. 50QCh. 25 - Prob. 51QCh. 25 - Prob. 52QCh. 25 - Prob. 53QCh. 25 - Prob. 54QCh. 25 - Prob. 55Q
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