The Graph Above Shows 4 Models for How the Average

Multiple Choice

The graph above shows 4 models for how the average distance between galaxies could change with time, from the past (left) to now (middle) to the future (right hand side) . The graph also shows real data, based on studies of supernovae. Each black dot on the graph is for one supernova explosion. The data are plotted with dots and black lines that indicate the range of uncertainty of each individual measurement. Use this graph to answer the following questions about cosmological models for the expansion of the universe. (Note that the models are in the same order, from top to bottom, whether on the right hand side of the graph or the left hand side. For example the accelerating model is the top line on both sides of the graph. You should also have a handout with a better version of this graph.) Which model(s) predict that galaxies are getting farther apart NOW?

A) Accelerating
B) Coasting
C) Critical
D) Recollapsing
E) All of them. F) None of them.