Description: 宇宙微波背景（CMB）是宇宙大約 38 萬年前，光與重子解耦自由傳播遺留至今的電磁輻射。它提供了有關宇宙的組成、幾何（形狀）、演變和結構演化的信息。早期的緻密宇宙是由自由粒子（質子、中子、電子）和光（光子）組成的 "熱湯"。在CMB產生之前，光子與自由電子的相互作用阻礙了光的遠距離傳播。宇宙的膨脹和冷卻使自由電子與質子結合形成氫原子，並使光得以在宇宙中傳播。宇宙膨脹隨後拉長了這些光子的波長，使它們如今可以在電磁波譜的微波區域被探測到。

Related Terms:

• 宇宙大爆炸理論
• 宇宙學
• 暗能量
• 微波輻射
• 電子

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This is an automated transliteration of the simplified Chinese translation of this term

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