El fondo cósmico de microondas

The video explores the cosmic microwave background, a crucial test for the Big Bang theory, discovered in 1964 by two American astronomers. This background is a uniform signal from all directions, representing the farthest back in time we can see, as the universe was once opaque. Initially, the universe was too hot for electrons and protons to form hydrogen atoms, but as it cooled, light could travel freely, allowing us to detect these photons today. The cosmic microwave background resembles blackbody radiation with a temperature of 2.7º Kelvin. The universe was about 400,000 years old when this occurred, much younger than its current 13.7 billion years. To observe earlier events, different methods beyond light are needed.

What conditions in the early universe prevented light from traveling freely?

At what age was the universe when the cosmic microwave background became detectable?