Twenty years ago, scientist George Smoot announced that Nasa's Cosmic Background Explorer mission - Cobe - had observed radiation from "the oldest and largest structures" in the early Universe. "If you're religious, it's like seeing God," he told reporters.

Since then, other spacecraft have built upon Cobe's work - learning more about the "oldest light" any telescope can detect.

Here, Professor of Astrophysics at the University of Sussex, Andrew Liddle, looks back to how this microwave radiation was first discovered - by accident - and Cobe's breakthrough moment of 1992.

Click bottom right for individual image information.

Most images courtesy Nasa, Esa and Science Photo Library. Music by Empire of the Sun and KPM Music.

Slideshow production by Paul Kerley and Dr Darren Baskill. Publication date 23 April 2012.

Related:

Cobe at 20

WMap

Esa Planck

University of Sussex

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