What is Expanding and What Is Not?

• What is Expanding and What Is Not?

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• 1. The observed redshift leads us to conclude that it is clusters of galaxies that are moving away from us.

• • In certain instances, individual galaxies within the local group are moving toward us.
  • The expansion of the universe corresponds to clusters of galaxies moving farther apart from each other.

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• 2. A gravitationally bound object is not expanding due to the expansion of the universe.