Did the universe start as a hot, dense point?
Cosmic Background Explorer
Did the universe start as a hot, dense point?
Imagine you're baking a cake, and the recipe says it needs to cool down slowly from a very hot temperature to room temperature. What if you could measure how uniformly the cake cools down from the top to the bottom?
The cosmic microwave background radiation (CMB) is like the cooling cake, showing us how uniformly the universe cooled down after its birth. The CMB's near-perfect black-body spectrum and faint anisotropies are clues about this cooling process.
Example
Just like measuring the temperature of different parts of the cake to see if it cools evenly, scientists measure the CMB to understand the early universe's cooling.
Remember this
The CMB's uniformity and slight variations tell us about the universe's first moments after the Big Bang.
Text adapted from Wikipedia, licensed under CC BY-SA 4.0.
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