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Cosmic Background

October 1, 2015

In the 1960s, two astronomers at Bell Laboratories were trying to map the radio waves coming from the Milky Way galaxy. But their observations were “noisy” — there was a lot of static.

So Robert Wilson and Arno Penzias did everything they could to track it down. They decided the static wasn’t coming from anything on Earth, in the galaxy, or in other galaxies. It wasn’t coming from their antenna, either. Instead, it was a steady signal that seemed to come from everywhere — every direction, day and night.

Wilson and Penzias soon discovered that other astronomers had theorized that the “afterglow” of the Big Bang would produce such a signal. In fact, a team was getting ready to look for that “static” in the sky.

Now, though, they didn’t need to. Some of the static in the telescope was coming from that afterglow — known today as the cosmic microwave background. The discovery provided strong evidence in support of the Big Bang.

Since then, that background has provided even more. It’s shown us the first structure in the early universe — the “kernels” from which galaxies and clusters of galaxies grew. And it’s provided evidence for the idea that a mysterious dark energy accounts for most of the matter and energy in the universe — discoveries made possible by experiments with a radio telescope half a century ago.

We’ll have more about the cosmic background tomorrow.

Script by Damond Benningfield, Copyright 2015

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