From the July 2015 issue

What happens if string theory is wrong?

An increasing number of physicists are skeptical that string theory can unite the fundamental forces of nature.
By | Published: July 27, 2015 | Last updated on May 18, 2023
String theory
If string theory is true, our universe has extra dimensions that lie curled up at every point around us.
Astronomy: Roen Kelly
For more than a decade, the American public has been fascinated with string theory. Science popularizers like Brian Greene produced hit TV documentaries that examined this mathematical construct. Could string theory unite physics into one grand unified theory? Perhaps, but with strange implications like extra dimensions and, possibly, even a multiverse.

The topic has since slowly faded from regular media coverage. And some physicists now view strings as a failed theory because it doesn’t make useful predictions about the universe. The debate has accelerated as the Large Hadron Collider hasn’t found any hints of an underlying “new physics,” as many theorists predicted it would.

In 2013, theoretical physicists attending a conference were asked a few simple questions about their current beliefs. Voters split evenly — a total of roughly one-quarter each — for and against string theory’s prospects to unite physics. The remaining physicists said that string theory wasn’t likely to pan out, but it was at least a step in the right direction.

A poll is no way to determine what is and isn’t good science, but it can tell you what scientists are currently thinking. And, for now, it looks like string theory is out.

So what would that mean for the universe? What if string theory is wrong?

Read on for Astronomy magazine’s analysis.

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