Describe the age and temperature of stars that make up spiral galaxies and their location.

Indicate whether the following statements are true or false. (Select T-True, F-False. If the first is T and the rest F, enterTFFFFF). A) The three main classifications of galaxies are elliptical, spiral and prime.B) The mass of a spiral galaxy can be found from its rotational velocity. The greater the rotation, the greater the mass.C) Galaxies sometimes collide with each other.D) It wasn't until the 1920s that we knew the Milky Way was only one of many galaxies.E) Most galaxies are elliptical.F) The shorter the pulsation period of a Cepheid variable star, the more luminous it is.

An astronomer in an imaginary Universe observes a small patch of the sky (0.005% of the total) with very deep observations and finds one million galaxies. How many galaxies can they estimate to be present in the whole Universe? 10 billion 20 billion 50 billion O 70 billion

For the graph shown above, a) what quantity would you label the y-axis with if the distance is between galaxies and the Earth? Explain your answer. Think through what we know is happening, motion-wise, out there in the galaxy. b) Also explain why you think there are dots and a solid line, on the graph.

Distance Based on the graph above, the expansion rate of galaxies near us is than galaxies that are farther away. O faster slower O the same rate Velocity

Suppose you have obtained spectra of several galaxies and have measured the observed wavelength of the H-Alpha line (rest wavelength = 656.3 nm) to be Galaxy 1: 658.1 nm. Galaxy 2: 667.1 nm. Galaxy 3: 677.6 nm. Calculate the radial velocity of each of these galaxies.