We receive today the light from a distant galaxy and from its spectrum we conclude that it took 400 Myr for the photons to reach us. Which one of the following statements is correct? O The Universe is accelerating, so that galaxy is moving toward us at higher speed and it will take less than 400 Myr for future photons from that galaxy to reach us. O That galaxy is 400 million light years away from us today. O That galaxy is moving away from us, so today it is more distant from us than 400 million light years. O We are observing that galaxy as it was in the past, and today it is accelerating toward us.

We receive today the light from a distant galaxy and from its spectrum we conclude that it took 400 Myr for the photons to reach us. Which one of the following statements is correct? O The Universe is accelerating, so that galaxy is moving toward us at higher speed and it will take less than 400 Myr for future photons from that galaxy to reach us. O That galaxy is 400 million light years away from us today. O That galaxy is moving away from us, so today it is more distant from us than 400 million light years. O We are observing that galaxy as it was in the past, and today it is accelerating toward us.

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

See similar textbooks

Similar questions

Use Wien's Law to calculate the peak wavelength of light coming from the Sun. Assume T=5800 K for the surface temperature of the Sun. Wein's displacement law says that the blackbody temperature and peak wavelength multiplied together give a constant of 0.29 cm-K. (K is degrees Kelvin). Convert the wavelength from part A into a frequency. The product of wavelength and frequency for electromagnetic radiation is a constant, the speed of light (c), 3 x 10^10 cm/s.
The radio galaxy Cygnus A possesses a lobe of plasma that is detected by both radio and X-ray observatories. The temperature of the X-ray-emitting plasma is 4 keV and the number density of the particles in the plasma is 4x103 m-3. Assume that the plasma is composed solely of completely ionized hydrogen, so the number densities of protons and electrons per cubic meter are identical. * the given number density of particles corresponds to the number density of hydrogen nuclei, so you can safely assume that the number density of electrons is equivalent to this number density a) Compute the collision frequency in Hertz between electrons and ions in the plasma. b) Compute the Debye wavelength in meters of the plasma. c) Compute the plasma parameter of the plasma.
If you have a positive look (pi+, mass: mpi = 2.50 x 10-28 kg) at rest and it decays to a positive muon (u+, mass: mu = 1.88 x 10-28 kg) and a neutrino. 1. How much gas is released during the decay process in MeV? If the rest mass of a neutrino is assumed to be negligible. 2. Why is the neutrino required for this decay to occur?
I am unsure where f3 should go from the black dot and the length/direction should it be?
I'm still confused about the step 2 part. How would I put this into my calculator? Where do the extra numbers 232.6 come from?
Please don't provide handwritten solution ...
The radio galaxy Cygnus A possesses a lobe of plasma that is detected by both radio and X-ray observatories. The temperature of the X-ray-emitting plasma is 4 keV and the number density of the particles in the plasma is 4x103 m-3. Assume that the plasma is composed solely of completely ionized hydrogen, so the number densities of protons and electrons per cubic meter are identical. * the given number density of particles corresponds to the number density of hydrogen nuclei, so you can safely assume that the number density of electrons is equivalent to this number density a) Compute the temperature of the plasma in Kelvin. b) Using the calculated temperature for the plasma, compute the mean velocity in meters per second of an electron within the plasma. c) Compute the Coulomb cross section in square meters for a collision between an electron and a proton in the plasma.
What is the wavelength, in fm (femtometers, or 10^-15 m), of a proton travelling at 90% of the speed of light?