Red-shift Practice Questions

Describe what is meant by red-shift.

Which statement describes the Big Bang theory?

Tick (✓) one box.

• The universe has always been the same size.
• The universe began from a very small region that was extremely hot and dense.
• The universe began as a large, cold cloud of gas that slowly collapsed.
• The universe is expanding into a much larger empty space that already existed.

Since 1998, observations of supernovae in very distant galaxies have been made.

What do these observations suggest?

Tick (✓) one box.

• Distant galaxies are moving towards the Earth.
• Distant galaxies are moving away at a constant speed.
• Distant galaxies are receding ever faster.
• Distant galaxies have stopped moving.

There is still much about the universe that scientists do not understand.

Name two examples of things about the universe that are not understood.

Which galaxy, P or Q, shows the greater red-shift?

Use Figure 1 to explain how you can tell.

Explain what Figure 1 tells you about the speeds and the distances of galaxies P and Q.

Light from which galaxy in Table 1 would show the smallest observed increase in wavelength?

Give a reason for your answer.

Describe the relationship between the distance of a galaxy from Earth and its speed of recession.

A fifth galaxy is 700 million light-years from Earth.

Use Table 1 to estimate the speed at which this galaxy is moving away from Earth.

Explain how the data in Table 1 provides evidence that the universe is expanding.

Describe what happens to the dots on the surface of the balloon as the balloon is blown up.

Explain how this model helps to explain the red-shift observed in light from distant galaxies.

Explain how scientists are able to use observations, such as those made by Hubble, to arrive at theories such as the Big Bang theory.

Since 1998, astronomers have measured the brightness of a particular type of supernova in very distant galaxies.

State what these measurements suggest about the motion of very distant galaxies.

Give the reason why scientists had to change their ideas about the universe after 1998.

Light from almost every distant galaxy is red-shifted, and the size of the red-shift is different for different galaxies.

Explain how observations of the light from distant galaxies led scientists to the Big Bang theory, and why this model of the universe has been developed further since 1998.