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 significant discovery did two American astronomers make in 1964 that supports the Big Bang theory?

• The existence of black holes

• The expansion of the universe

• The cosmic microwave background

• The theory of relativity

Why was the early universe described as opaque?

• Because it was filled with dark matter

• Because light could not travel freely due to constant collisions with particles

• Because it was covered by cosmic dust

• Because it was too cold for light to exist

What allowed photons to finally travel freely in the universe?

• The universe stopped expanding

• The universe became hotter

• The universe cooled down enough for electrons and protons to combine

• The universe was filled with dark energy

What is the temperature of the cosmic microwave background radiation?

• 100 Kelvin

• 2.7 Kelvin

• 0 Kelvin

• 273 Kelvin

How old was the universe when the cosmic microwave background was formed?

• 10 billion years

• 13.7 billion years

• 400,000 years

• 1 million years