What key event happened during the decoupling epoch?
A)Pairs of neutrons and protons were created.
B)Electrons and positrons were created.
C)Expansion cooled the universe enough that protons could capture electrons in orbit.
D)Dark energy accelerated the cosmos on to infinity.
E)The universe underwent a brief period of very rapid expansion.

Question

Quizplus · Accepted Answer

During the decoupling epoch, which occurred around 380,000 years after the Big Bang, the universe had expanded and cooled enough for protons to capture electrons and form neutral atoms, allowing light to travel freely through space. This is referred to as recombination and is the key event that made the universe transparent to light. Therefore, C is the best choice as it accurately describes this event. During the decoupling epoch, which occurred around 380,000 years after the Big Bang, the universe had cooled down enough to allow protons to capture electrons to form neutral hydrogen atoms. This event is known as recombination, and it allowed photons to travel freely through space for the first time, creating the cosmic microwave background radiation that we observe today.

What Key Event Happened During the Decoupling Epoch