Why does everything in the universe seem to be moving away from us?
Expansion of the universe
Why does everything in the universe seem to be moving away from us?
Imagine you're standing in a field, throwing a ball to a friend. As you throw, your friend runs away at a constant speed. The farther they get, the harder it is to catch the ball.
In the universe, everything is like your friend running away as you throw the ball. The farther away they get, the faster they seem to move from your perspective. This is because the universe itself is expanding, and everything is moving away from everything else.
Example
If your friend is 10 meters away and running at 5 meters per second, they seem to move away at 10 meters per second from your perspective. In the universe, as galaxies are 10 billion light-years apart, they appear to move away at speeds proportional to their distance.
Remember this
The universe's expansion makes distant galaxies appear to move away faster, providing evidence for the Big Bang theory.
Text adapted from Wikipedia, licensed under CC BY-SA 4.0.
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