Chapter 34: Q5PE (page 1238)
On average, how far away are galaxies that are moving away from us at\({\rm{2}}{\rm{.0 \% }}\)of the speed of light?
Short Answer
The direction is obtained as: \(d{\rm{ = 300 Mly}}\).
Chapter 34: Q5PE (page 1238)
On average, how far away are galaxies that are moving away from us at\({\rm{2}}{\rm{.0 \% }}\)of the speed of light?
The direction is obtained as: \(d{\rm{ = 300 Mly}}\).
All the tools & learning materials you need for study success - in one app.
Get started for freeOur solar system orbits the center of the Milky Way galaxy. Assuming a circular orbit\({\rm{30,000 ly}}\)in radius and an orbital speed of\({\rm{250 km/s}}\),how many years does it take for one revolution? Note that this is approximate, assuming constant speed and circular orbit, but it is representative of the time for our system and local stars to make one revolution around the galaxy.
Another known cause of red shift in light is the source being in a high gravitational field. Discuss how this can be eliminated as the source of galactic red shifts, given that the shifts are proportional to distance and not to the size of the galaxy.
(a) What is the approximate speed relative to us of a galaxy near the edge of the known universe, some\({\rm{10 Gly}}\)away? (b) What fraction of the speed of light is this? Note that we have observed galaxies moving away from us at greater than\({\rm{0}}{\rm{.9c}}\).
Suppose black holes radiate their mass away and the lifetime of a black hole created by a supernova is about \({\rm{1}}{{\rm{0}}^{{\rm{67}}}}\)years. How does this lifetime compare with the accepted age of the universe? Is it surprising that we do not observe the predicted characteristic radiation?
Andromeda galaxy is the closest large galaxy and is visible to the naked eye. Estimate its brightness relative to the Sun, assuming it has luminosity\({\rm{1}}{{\rm{0}}^{{\rm{12}}}}\)times that of the Sun and lies\({\rm{2 Mly}}\)away.
What do you think about this solution?
We value your feedback to improve our textbook solutions.