Cosmic ripples come into focus
The most detailed map of ripples in radiation left over from the big bang – known as the cosmic microwave background, or CMB – will let cosmologists hone their theories of how the universe evolved.
This new view of the CMB comes from the European Space Agency's Planck satellite. Just how sharp is it? Find out using the slides below, which show the Planck map and its predecessors alongside corresponding images of the Earth, blurred to mimic the cosmic maps’ resolution.
Ripples revealed: COBE, 1992 George Smoot of the University of California at Berkeley said that viewing the CMB map produced by NASA's Cosmic Background Explorer satellite was like "looking at God". Maybe if you're short-sighted – viewing the Earth at the same resolution, we can make out the continents, but little more. But as it was the first time ripples in the CMB had come into view, Smoot's excitement was justified; later he would share a Nobel prize for the work.
Source: NASA/European Space Agency; graphic by Adam Becker and Peter Aldhous, published 22 March 2013.
Big leap forward: WMAP, 2003 As these images make clear, NASA's Wilkinson Microwave Anisotropy Probe transformed our view of the CMB. Its first map, released in February 2003, indicated that the very early universe was dominated by a rapid period of expansion called inflation. Still, the mission threw up some puzzling results, notably that hot and cold spots in the CMB were not scattered at random, but instead align along what has been dubbed an "axis of evil".
Source: NASA/European Space Agency; graphic by Adam Becker and Peter Aldhous, published 22 March 2013.
Sharper, older, but still evil: Planck, 2013 The latest view of the microwave sky is crisper still, and brings the equivalent image of our home planet into sharp focus. Planck's new data agrees well with cosmological theory. It suggests the age of the universe is 13.82 billion years – about 80 million years older than previous estimates – and indicates that dark energy contributes slightly less to the universe than was thought. The puzzling axis of evil remains.
Source: NASA/European Space Agency; graphic by Adam Becker and Peter Aldhous, published 22 March 2013.
WMAP's limits: Goodbye, Cornwall The gulf between WMAP's and Planck's views of the cosmos becomes clearer if we zoom in on the region of the sky that corresponds to Europe in our companion image of the Earth. At the resolution of WMAP's 2003 map, the continent's rough outline is familiar enough, but Sicily becomes a blur, while Cornwall in southwest England merges into Wales.
Source: NASA/European Space Agency; graphic by Adam Becker and Peter Aldhous, published 22 March 2013.
Planck's triumph: Hello, Crete By contrast, the same region as observed by Planck reveals intricate fluctuations in the CMB. On the corresponding image of Europe, details including the Alps and the narrow island of Crete appear. Cosmologists will now be rushing to work out what this new level of detail means for our understanding of the universe. In other words: what is the cosmic equivalent of discovering the Alps?
Source: NASA/European Space Agency; graphic by Adam Becker and Peter Aldhous, published 22 March 2013.