A distant galaxy is observed with a spectrometer. This galaxy produces an emission line that is identified as a Hydrogen transition that normally has a wavelength of 21 cm. For this galaxy, however, the emission line is observed at a wavelength of 33 cm. How fast is this galaxy moving away from us in units of km/s [round off your answer to 1 km/s]

Suppose an alien race on a distant planet tries to send a message to us, with a laser (light). However, we were unaware that there is a stellar-mass black hole almost directly between us and them. How would this complicate our attempts to locate their position in the Galaxy? O Gravitational lensing would make the signal appear to be coming from a different location O The information carried by the laser (light) would be altered O It would not matter The black hole absorbs all of the light

If a galaxy is receding from us at 0.10c. Use Hubble's law to estimate the distance to this galaxy if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 S O 1.4 × 10^9 ly O 6.6 × 10^5 ly 6.6 × 10^5 Mly O 2.2 Mly

A 1.6 GHz radio signal is detected from a galaxy as 0.86GHz. Estimate the relative velocity.