Capture the cosmos > Stellar evolution > Dig deeper (cont'd) > Tales of: The early cosmos: Out of the darkness

Tales of ... The early cosmos: Out of the darkness See image below

Imagine a night sky without the twinkling light from stars and galaxies piercing the darkness. Astronomers believe that this was the bleak picture of the universe for at least a hundred million years after the "big bang," a tremendous explosion that produced time, space, and matter about 14 billion years ago.

Although no stars and galaxies existed just after the big bang, the young cosmos was anything but dull. It was humming with activity.

The big-bang explosion ejected intense radiation and energy. In the beginning, physical conditions were so extreme that matter as we know it today did not exist. When the universe was about one millionth of a second old, the temperatures and densities dropped enough for protons and neutrons — the building blocks of atoms — to form. Within the next few minutes, the nuclei of light elements, such as hydrogen, helium, lithium, and boron, were created. When the universe cooled to about 5,400 degrees Fahrenheit (3,000 degrees Celsius), atomic nuclei could finally capture electrons to form atoms. By 300,000 years, the universe was made up mostly of clouds of hydrogen and helium atoms.

As the universe expanded and cooled, some regions of space had slightly higher densities of hydrogen. As millions of years passed, the slight differences grew large, as dense areas drew in material because they had more gravity. Researchers have dubbed this period of coalescing the "dark ages." (Continued >>)

This is an artist's impression of how the very early universe might have looked as a firestorm of star formation took place.

Capture the cosmos > Stellar evolution > Dig deeper (cont'd) > Tales of: The early cosmos: Out of the darkness