Let poetic, of course, and I'm sure subject to debate but this appealed to me today:
1 In the beginning God created the universe in a BIg Bang
2 And the universe was without form, and filled with plasma; and darkness was upon the face of the plasma. And the Spirit of God moved upon the fog of the plasma.
3 And God said, Let the the universe cool and the cooling allow light.
4 And God saw the light, that it was good: and God's laws had divided the light from the darkness.
At the beginning of the Universe, within minutes of the Big Bang, space was filled with a hot, dense fog of ionized plasma. What little light there was wouldn't have penetrated this fog; photons would simply have scattered off the free electrons floating around, effectively making the Universe dark.
As the Universe cooled, after about 300,000 years, protons and electrons began to come together to form neutral hydrogen (and a little bit of helium) gas. Most wavelengths of light could penetrate this neutral medium, but there was very little in the way of light sources to produce it. But from this hydrogen and helium, the first stars were born.
Those first stars delivered radiation that was strong enough to peel electrons away from their nuclei and reionize the gas. By this point, however, the Universe had expanded so much that the gas was diffuse, and could not prevent light from shining out. By about 1 billion years after the Big Bang, the end of the period known as the cosmic dawn, the Universe was entirely reionized. Ta-da! The lights were on.
1 In the beginning God created the universe in a BIg Bang
2 And the universe was without form, and filled with plasma; and darkness was upon the face of the plasma. And the Spirit of God moved upon the fog of the plasma.
3 And God said, Let the the universe cool and the cooling allow light.
4 And God saw the light, that it was good: and God's laws had divided the light from the darkness.
We Finally Know What Turned The Lights on at The Dawn of Time
At the beginning of the Universe, within minutes of the Big Bang, space was filled with a hot, dense fog of ionized plasma. What little light there was wouldn't have penetrated this fog; photons would simply have scattered off the free electrons floating around, effectively making the Universe dark.
As the Universe cooled, after about 300,000 years, protons and electrons began to come together to form neutral hydrogen (and a little bit of helium) gas. Most wavelengths of light could penetrate this neutral medium, but there was very little in the way of light sources to produce it. But from this hydrogen and helium, the first stars were born.
Those first stars delivered radiation that was strong enough to peel electrons away from their nuclei and reionize the gas. By this point, however, the Universe had expanded so much that the gas was diffuse, and could not prevent light from shining out. By about 1 billion years after the Big Bang, the end of the period known as the cosmic dawn, the Universe was entirely reionized. Ta-da! The lights were on.