Distances to very remote galaxies are estimated based on their apparent type, which indicate the number of stars in thegalaxy, and their measured brightness. Explain how the measured brightness would vary with distance. Would there be anycorrection necessary to compensate for the red shift of the galaxy (all distant galaxies have significant red shifts)? Discusspossible causes of uncertainties in these measurements

In the reading, you were told that there were roughly 10,000 galaxies in the image of the Hubble Ultra Deep Field alone. The image is roughly 10 square arcminutes and there are roughly 1.5*10^8 square arcminutes composing the entire sky. With that in mind and assuming that the Hubble Ultra Deep Field represents an average part of the sky, roughly how many galaxies may exist in the observable universe? (Please include commas for every factor of 1,000; for example 2,343,567,890)

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.

A survey that uses Type la supernovae as standard candles to measure the distances to galaxies, combined with spectroscopic analysis of those galaxies Select one: to obtain their redshifts and recession velocities, yields the data shown in the The Universe is undergoing а. table. Use the data to sketch a diagram of velocity versus distance. Choose the accelerated expansion statement given below that can be O b. The Universe is contracting. inferred from the data. Velocities and distances to Ос. The data does not provide sufficient galaxies information to determine the rate of Distance (Mpc) expansion of the Universe. Velocity (km/s) 10 730 d. The expansion rate of the Universe is 250 16250 constant 500 30000 e. The expansion of the Universe is 800 40000 decelerating. 1000 45000

Subject: physics