Microwaves explained, information on the Wilkinson Microwave Anisotropy Probe (WMAP) and links to NASA pages for further reading, includes diagrams and sample microwave pictures.

Microwave Picture

The First Detailed Full Sky Picture of the Oldest Light in the Universe.

The Microwave Sky image from the WMAP Mission

What is this Picture?

If we make a temperature map of the Earth we get a pattern of data that can be displayed in a colourful way to help us understand the results. If we turn our gaze upward and make a picture of the whole sky, we can display that data in a similar oval format for easy examination.

The temperature map of the Earth is a picture of data from the Earth's surface. The image captured by WMAP is from when the temperature of the universe became low enough for atoms to form, allowing light to travel great distances (to us). It is analogous to the surface of the clouds we see on an overcast day. Light travels through the clouds, but we only see the detail on the cloud's surface.

The light that is reaching us has been stretched out as the universe has stretched, so light that was once beyond gamma rays is now reaching us in the form of microwaves. Microwaves are the same as the light we see with our eyes, but stretched out to a longer wavelength.

The Wilkinson Microwave Anisotropy Probe (WMAP) team has made the first detailed full-sky map of the oldest light in the universe. It is a 'baby picture' of the universe. Colours indicate "warmer" (red) and "cooler" (blue) spots. The oval shape is a projection to display the whole sky; similar to the way the globe of the earth can be projected as an oval.

The microwave light captured in this picture is from 379,000 years after the Big Bang, over 13 billion years ago: the equivalent of taking a picture of an 80-year-old person on the day of their birth.

The Light in Sharp Focus

In 1992, NASA's COBE mission first detected tiny temperature fluctuations (shown as colour variations) in the infant universe, a landmark discovery.

The data brings into high resolution the seeds that generated the cosmic structure we see today. These patterns are tiny temperature differences within an extraordinarily evenly dispersed microwave light bathing the Universe, which now averages a frigid 2.73 degrees above absolute zero temperature. WMAP resolves slight temperature fluctuations, which vary by only millionths of a degree. The new data support and strengthen the Big Bang and Inflation Theories.

For further information, go to NASA