Gravitational wave detection a big day for the Big Bang

On a snowy St. Patrick’s Day, our offices officially shut down by a late-winter storm, the Science News staff was abuzz over the biggest thing since the Higgs boson. On March 17, scientists announced the first direct evidence of the theory of cosmic inflation: primordial gravitational waves. The news spread fast, even rippling out to the front page of the New York Times.

Cosmic expansion was one of the most important discoveries of the 20th century; before Einstein and Hubble, people assumed the universe was static. Explaining the universe’s expansion led to the idea of the Big Bang and later to inflation (SN: 7/28/12, p. 20): a moment of explosive, exponential growth in the moments after the Big Bang that accounts for the uniformity of the visible universe, among other things. The universe grew from a speck smaller than a proton to something more akin to a softball in a tiny fraction of a second. Soon after, the theory goes, the ballooning universe slowed down to a more leisurely pace.

Working at home and listening in to a glitchy webcast of the press conference, astronomy writer Christopher Crockett reported the biggest science story in months, if not years. As he describes in our lead news story, scientists have discovered the signatures of primordial gravitational waves in the cosmic microwave background, leftover radiation from the early universe. This offers the strongest evidence to date for inflation, and suggests a universe more vast than once imagined. The gravitational waves were stronger than expected, which gives some skeptics pause. But, as one of Crockett’s sources told him, that will also send theorists running to the blackboard to try to explain the discrepancy. If confirmed by other teams and data from the Planck mission, this could lead to new physics.

Tom Siegfried reports on some other intriguing data from the Planck mission in “Cosmic Question Mark.” In his Context blog, Siegfried also tackles the latest news by filling in the backstory of the search for gravitational waves and calling the discovery “a landmark in the history of physics.” He points out that, in most models, if you have inflation, you also get multiverses. For the starry-eyed, that’s news worthy of some big buzz. 

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