Chapter 34: Q3CQ (page 1236)
Question: If the universe is infinite, does it have a center? Discuss.
Because there is always an equal amount of space surrounding every point and the universe expands uniformly, all points are equivalent and there is no centre.
Over 30 million students worldwide already upgrade their learning with Vaia!
All the tools & learning materials you need for study success - in one app.
Get started for free
On average, how far away are galaxies that are moving away from us at\({\rm{2}}{\rm{.0 \% }}\)of the speed of light?
Distances to the nearest stars (up to\({\rm{500 ly}}\)away) can be measured by a technique called parallax, as shown in Figure\({\rm{34}}{\rm{.26}}\). What are the angles\({{\rm{\theta }}_{\rm{1}}}\)and\({{\rm{\theta }}_{\rm{2}}}\)relative to the plane of the Earth’s orbit for a star\({\rm{4}}{\rm{.0 ly}}\)directly above the Sun?
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.
If neutrino oscillations do occur, will they violate conservation of the various lepton family numbers (\({{\rm{L}}_{\rm{e}}}\),\({{\rm{L}}_{\rm{\mu }}}\), and \({{\rm{L}}_{\rm{T}}}\))? Will neutrino oscillations violate conservation of the total number of leptons?
(a) A particle and its antiparticle are at rest relative to an observer and annihilate (completely destroying both masses), creating two\({\rm{\gamma }}\)rays of equal energy. What is the characteristic\({\rm{\gamma }}\)-ray energy you would look for if searching for evidence of proton-antiproton annihilation? (The fact that such radiation is rarely observed is evidence that there is very little antimatter in the universe.) (b) How does this compare with the\({\rm{0}}{\rm{.511 MeV}}\)energy associated with electron-positron annihilation?
What do you think about this solution?
We value your feedback to improve our textbook solutions.
