The WMAP satellite travels vast distances to outermost reaches of our universe, essentially travelling back in time to look at the very early universe.

In 2001 NASA launched a satellite called WMAP. Its mission: to capture the very first light of the universe — light from the Big Bang.

Most people think of the Big Bang as a monumental explosion that happened in one place and radiated out from the center. But cosmologist Max Tegmark tells Alan the universe never had a center, and the Big Bang didn't either. Instead, space was and is elastic, constantly stretching so that everything moves farther away from everything else. Or, as Alan puts it, the Big Bang was more like the Infinite Taffy Pull.

How energy from the Big Bang eventually led to the creation of our universe remains one of the great mysteries of our cosmos. Alan travels to the Las Campanas observatory in Chile, home to two of the world's most powerful telescopes, where astronomers Alan Dressler and Pat McCarthy are looking for answers.

Alan learns from Miguel Roth and Alan Dressler about analyzing light spectra.

Dressler and McCarthy use the telescopes not only to photograph distant galaxies but also to record specific data about the color of the light they give off. Nearly everything we know about stars and galaxies comes from analyzing their light spectra. The color properties of the light from a star-how much red, green or blue light there is, for instance-tell scientists how hot the star is. The telescopes at Las Campanas can also reveal what a star is made of and how big it is.

Dressler and his team are using this data from billions of stars to map the evolution of the universe from as far back as 7 billion years ago. They hope this reconstruction will help scientists understand how our highly diverse universe developed from a featureless, roiling cauldron of energy and matter.

For more on this topic, see the web feature:
The Astronomer's Toolkit