Author Question: Given that the universe is about 14 billion years old, which of the following statements is ... (Read 32 times)

ARLKQ · **on:** Jul 27, 2018

Given that the universe is about 14 billion years old, which of the following statements is logically valid?

A) All galaxies nearby us are about 14 billion years old.
B) All galaxies that we can see are about 14 billion years old.
C) All galaxies that we see have an age that is approximately equal to the age of the universe today, minus the lookback time (or light travel time) corresponding to the redshift of that galaxy.
D) The oldest galaxies we see at great distances are younger than the oldest galaxies we see nearby.

Question 2

The amount of gravitational potential energy released as an object falls depends on

A) its mass and the distance it falls, as well as the rate of gravitational acceleration.
B) its mass and its speed at the time it begins falling.
C) only the distance it falls.
D) only its mass.
E) only its speed at the time it begins falling.