Question

The Big Bang theory states that the universe was formed in an instant, about 13.8 billion years ago, in an enormous explosion. The universe expanded from an extremely small, hot, and dense single point. Since then, the universe has been expanding and will continue to expand. The color of light emitted from galaxies and stars, cosmic background radiation (leftover electromagnetic radiation), and the expanding universe are evidence for the Big Bang.



A group of students collect data about the distance of three galaxies from Earth in millions of light years (Mly). Their data is shown.



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The following question has two parts. First, answer Part A. Then, answer Part B.



Part A:

What can be concluded from the data in the table?


The galaxies are larger in present day compared to the early 20th century.


The galaxies are smaller in present day compared to the early 20th century.


The galaxies are closer to Earth in present day compared to the early 20th century.


The galaxies are farther from Earth in present day compared to the early 20th century.





Part B:

Which statement supports the answer in part A?


The universe is spinning.


The universe is stationary.


The universe is expanding.


The universe is compressing.

Answer 1

Part A: The galaxies are farther from Earth in present day compared to the early 20th century.

Part B: The universe is expanding.

Reason: The measured distances increase over time, which indicates galaxies are moving away from us — evidence of cosmic expansion.