The first one to form is Hydrogen. Then, over the next 3 minutes the Universe begins to create two more elements, helium and lithium.We went from a Universe that was infinitely small to a Universe that was light-years in size. In the first 3 minutes, essentially everything interesting that was going to happen in the Universe happened.

Well, not quite. If you were there, you couldn't see it.When we look at the night sky, we can see a literally billions of years into the past. And we think it's always been that way. Nope, not true. 380 thousand years after the Big Bang, that's when the Universe began to become transparent. But before then, it was milky.

There was a milky soup of loose electrons. The young Universe has to cool down enough for the electrons to slow down and stick to new atoms. It took a long time for all of the hydrogen, helium and lithium atoms in the Universe to form. Scientists calculate it took 380 thousand years for the electrons to slow down enough so that the Universe could start mass producing atoms. When that happens, the milky fog clears. The first light escapes and raises across the Universe.

Nearly 14 billion years later, two young scientists in New Jersey picked it up by accident.In 1964, Arno Penzias and Robert Wilson were mapping radio signals across our galaxy. Everywhere they looked, they picked up a strange background hum. They first suspected their equipment, maybe pigeon droppings on the antenna were causing the strange signal. But after cleaning the antenna, the mysterious hum remained, so much for pigeon droppers.

Penzias delivered a talk at Princeton University. And according to law, one person in the back said,"either you have discovered the effects of bird-droppings or the creation of the Universe."