The Andromeda Galaxy (M31) and our Milky Way Galaxy are prominent members of the Local Group. The Andromeda Galaxy is currently moving towards the Milky Way at a speed of approximately 110 km s−1110\text{ km s}^{-1}110 km s−1, and the distance between them is approximately 780 kpc780\text{ kpc}780 kpc.
Explain why these specific observational data cannot be used to determine the Hubble constant, and hence estimate the age of the Universe.
An extremely distant quasar, such as TON 618, is powered by a hypermassive black hole at its core. Suppose the mass of this central black hole is measured to be 3.80×10103.80 \times 10^{10}3.80×1010 solar masses.
Calculate the radius of the event horizon of this black hole. State an appropriate unit for your answer. (Take 1 solar mass=1.99×1030 kg1\text{ solar mass} = 1.99 \times 10^{30}\text{ kg}1 solar mass=1.99×1030 kg, G=6.67×10−11 N m2 kg−2G = 6.67 \times 10^{-11}\text{ N m}^2\text{ kg}^{-2}G=6.67×10−11 N m2 kg−2, and c=3.00×108 m s−1c = 3.00 \times 10^8\text{ m s}^{-1}c=3.00×108 m s−1.)
Quasars are among the most distant and luminous objects in the known Universe, and are often associated with active galaxies undergoing violent interactions.
Explain the physical nature of a quasar and how interactions like galactic mergers trigger this phenomenon. In your response, you should:
