Signs of the Big Bang
The cosmic microwave background is the faint glow of radiation that remains from the primordial fireball--the Big Bang--that gave birth to the universe. Within a fraction of a second, the ultimate characteristics of our universe were set. Space-time expanded, the energy of the universe spread thinner and thinner, and the average temperature dropped--swiftly at first, more slowly later on. |
Big Bang Plus 1043 Second
This artist's conception represents the cosmos in the tiniest fraction of a second after the Big Bang. At this time the universe was much smaller and hotter and contained minute irregularities--bumps no larger than grains of sand would make under a bedsheet the size of a football field. Most theories then call for a period of rapid expansion known as inflation. |
Big Bang Plus 300,000 Years
In the Cosmic Background Explorer's sky map of the Milky Way, red indicates temperatures 0.005 percent warmer than the average sky temperature of 4.9 degrees Fahrenheit above absolute zero while blue represents temperatures 0.005 percent colder. Computer analysis shows a pattern of fluctuations that supports predictions based on the inflationary Big Bang theory. |
Big Bang Plus 13 Billion Years
Tiny differences in the gravitational fields in the young universe caused matter to start to clump together, weaving the "cosmic web" that is the large-scale structure of galaxies we see today. |