Baby Universe

A picture of our universe from the first moments of its existence helps explain why it looks the way it does.

Photo courtesy of NASA/WMAP Science Team The new picture of the early universe shows tiny temperature fluctuations in CMB, where red and blue colours indicate warmer and cooler spots. The white lines show the direction of polarisation of the oldest light.

For centuries, people have looked up at the stars and wondered why they are scattered the way they are in the night sky. Scientists still haven't completely solved this, but in March 2006 some researchers came a whole lot closer to understanding how our universe came to look the way it does. Using data from a NASA satellite, they were able to capture in the greatest detail yet a picture of the light from our universe dating back to instants after the Big Bang when it was first created. It's a breakthrough in cosmological research since it has allowed scientists to gaze back to the first trillionth of a second of our universe and distinguish between different versions of what happened in those crucial instants after the Big Bang.

The light that scientists are observing is cosmic microwave background radiation (CMB), or the afterglow of light that still remains from the Big Bang 13.7 billion years ago. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite, launched in 2001 and now a million miles from Earth in the direction opposite the sun, has been measuring minute temperature fluctuations in the afterglow for three years. In 2003, the temperature fluctuations it had recorded had produced a very detailed picture of the early universe and allowed scientists to get answers to questions about the age of the universe, its composition and how it developed. Since then, the satellite has been looking at polarisation, or the pattern of the residual afterglow, a signal less than a hundred times weaker that the previous temperature maps. This data has added detail to the picture obtained in 2003 and has determined that the first stars were formed 400 million years after the Big Bang. "This is brand new territory," said Princeton University physicist Lyman Page, a WMAP team member. "We are quantifying the cosmos in a different way to open up a new window for understanding the universe in its earliest times."