Astronomers infer that the universe is expanding because distant galaxies all appear to . Astronomers infer that the universe is expanding because distant galaxies all appear to . rotate rapidly be made mostly of dark matter be moving away from us, with more distant ones moving faster be growing in size

Stretch and moving away from us, with more distant ones moving faster

Explanation:

Astronomers observed that the entire universe is getting bigger because distant galaxies appears to be moving away from us

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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