Skip to main content

What's behind the Big Bang controversy?

By Meg Urry
updated 2:30 PM EDT, Fri June 6, 2014
Astronomers using the Hubble Space Telescope have pieced together this picture that shows a small section of space in the southern-hemisphere constellation Fornax. Within this deep-space image are 10,000 galaxies, going back in time as far as a few hundred million years after the Big Bang. Click through to see other wonders of the universe. Astronomers using the Hubble Space Telescope have pieced together this picture that shows a small section of space in the southern-hemisphere constellation Fornax. Within this deep-space image are 10,000 galaxies, going back in time as far as a few hundred million years after the Big Bang. Click through to see other wonders of the universe.
HIDE CAPTION
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
Wonders of the universe
<<
<
1
2
3
4
5
6
7
8
9
10
11
>
>>
STORY HIGHLIGHTS
  • Meg Urry: A controversy about the origin of the universe came to light this week
  • Urry: The idea that there was rapid "inflation" in the early universe is being questioned
  • She says controversy may be messy but that's how we make progress in science
  • Urry: Most scientists don't care about the "win" -- we care about getting nature right

Editor's note: Meg Urry is the Israel Munson professor of physics and astronomy at Yale University and director of the Yale Center for Astronomy and Astrophysics. The opinions expressed in this commentary are solely those of the author.

(CNN) -- Everyone wants to be right. Most of us sure hate being wrong.

But scientists know that new discoveries often change or even invalidate earlier ideas. Being wrong can mean we have learned something new.

Meg Urry
Meg Urry

This week, a controversy about the Big Bang and the origin of the universe came to light at the American Astronomical Society conference in Boston. In an invited lecture sponsored by the Kavli Foundation, Princeton astrophysicist David Spergel offered a different idea about a discovery made last March, where the BICEP2 Antarctic cosmology experiment reported evidence of a period of rapid "inflation" in the very early universe. Specifically, researchers detected the special pattern of polarization that would be caused by gravitational waves stretching and squeezing space itself during inflation.

Last week, three theorists -- Alan Guth, Andrei Linde and Alexei Starobinsky -- were awarded the prestigious Kavli Prize for astrophysics for their work developing the theory of cosmic inflation. (This prize and the AAS lecture were sponsored by the same foundation but were otherwise completely independent.) Their award may well have been prompted by the BICEP2 discovery, which generated a lot of excitement about early universe cosmology.

How the universe evolved?
A Big Bang breakthrough?
2010: World's biggest science experiment

But at the American Astronomical Society conference, Spergel argued that the BICEP2 results reported in March could instead be explained by a more pedestrian effect, namely, light scattering off dust between the stars in our Milky Way galaxy. If he is correct, the widely heralded BICEP2 announcement was premature at best and wrong at worst.

This kind of controversy is completely normal in science. It's the way science progresses. You put an idea out there and your colleagues -- many of them good friends and scientific collaborators -- try to shoot it down.

A scientist's first reaction to a new idea is often: "That's wrong because...." To which the proponent replies, "No, you are wrong because..." And so the debate begins.

No matter how much a scientist might hope to be right, nature holds the answer. One theory may be more beautiful than another, or more complicated, or more elegant, but nature doesn't know or care. The job of a scientist is to find out what the real answer is, not to advocate for any one point of view.

We do that by making careful measurements and assessing the accuracy of the result. BICEP2 detected certain polarization patterns in light from the cosmic microwave background, which they believe were created during inflation. David Spergel is instead suggesting the light was polarized by passing through galactic dust near the end of its journey to our telescopes -- indeed, he argued, this dust is expected to create the kind of polarization signal BICEP2 saw.

To support his contention, Spergel cited data from a space experiment called Planck, which like BICEP2 measures polarized light from the cosmic microwave background. Planck's ability to measure light at more wavelengths than BICEP2 gives it an advantage in diagnosing the effects of dust.

If the BICEP2 team is correct, they detected the first signs of gravitational wave distortions of space in the first one hundred millionth of a trillionth of a trillionth of a second of an early, extreme inflation of space -- an extremely important discovery.

If Spergel is correct, a significant signal from primordial gravitational waves has not yet detected and we need to keep looking for this critical probe of our universe.

New measurements from the Planck team are expected next fall. Maybe they will settle the controversy. Either way, an array of increasingly sensitive experiments will make still better measurements of the cosmic microwave background.

This is an important goal. Since the early universe is far hotter than any laboratory on Earth -- or, for that matter, in the most energetic regions around black holes or in the most massive clusters of galaxies -- it offers a very important experimental laboratory for testing fundamental physics theories.

That's one reason the debates will continue until one side convinces the other. But most scientists really don't care about the "win" -- we care about understanding nature.

Even Spergel, at the beginning of his address to the American Astronomical Society audience, called the BICEP2 results "heroic science" -- a very difficult measurement that pushes the limits of current technology.

Controversy and debate may be messy but that's how we make progress in science.

Follow us on Twitter @CNNOpinion.

Join us on Facebook.com/CNNOpinion.

ADVERTISEMENT
Part of complete coverage on
Space
updated 11:42 AM EDT, Fri October 24, 2014
If there's one thing we've learned about the CNN iReport community, it's that you all love to capture celestial events.
updated 10:42 PM EDT, Thu October 23, 2014
Up, up and away. Way away -- to the moon, in fact.
updated 3:58 PM EDT, Mon October 20, 2014
It was the closest comet near-miss known to astronomers, but everything is alright.
updated 9:04 AM EDT, Wed October 15, 2014
It wasn't a trick. But for space geeks, it sure was a treat.
updated 8:25 PM EDT, Sun October 12, 2014
Want to ride an elevator into space? A breakthrough in nanotechnology could mean we will be riding into space on a cable made of diamonds.
updated 1:52 PM EDT, Tue October 7, 2014
Astronauts lie motionless in a row of compartments with medical monitoring cables connected to their bodies, as their space ship cuts through the silent blackness.
updated 4:20 AM EDT, Tue October 7, 2014
The key to an astronauts' wellbeing has been found, somewhat contradictorily, to be a group of tiny organisms -- bacteria.
updated 3:29 PM EDT, Sat September 20, 2014
This image from the Hubble Space Telescope indicates that a huge ring of dark matter likely exists surrounding the center of CL0024+17 that has no normal matter counterpart.
Scientists are closer to seeing a vast, invisible universe as a spectrometer in Earth orbit picks up possible clues of dark matter.
updated 9:21 AM EDT, Wed September 10, 2014
The Soviets sent stray dogs up to conquer space. This is what happened next
updated 5:20 AM EDT, Thu August 28, 2014
Scientists believe that a hot gas bubble was formed by multiple supernovas.
updated 11:47 AM EDT, Wed August 27, 2014
Robonaut is the next generation dexterous robot
Life aboard the International Space Station.
updated 9:53 PM EDT, Tue August 26, 2014
NASA's New Horizons mission hurtles toward Pluto in historic 3 billion mile expedition.
updated 4:44 PM EDT, Wed August 6, 2014
Rosetta spacecraft arrives at its destination, Comet 67P after a 10-year journey around the solar system.
After a 10-year chase the Rosetta spacecraft is now orbiting a comet
updated 11:56 PM EDT, Mon July 14, 2014
Scientists looking for signs of life in the universe -- as well as another planet like our own -- are a lot closer to their goal than people realize.
updated 11:51 AM EDT, Sun June 29, 2014
If you think you saw a flying saucer over Hawaii, you might not be crazy -- except what you saw didn't come from outer space, though that may be its ultimate destination.
updated 9:47 PM EDT, Thu June 26, 2014
The U.S. space shuttle program retired in 2011, leaving American astronauts to hitchhike into orbit. But after three long years, NASA's successor is almost ready to make an entrance.
updated 10:21 AM EDT, Fri June 13, 2014
When I first poked my head inside Virgin Galactic's newest spaceship, I felt a little like I was getting a front-row seat to space history.
updated 3:27 PM EST, Tue February 25, 2014
From a sheep ranch in Western Australia comes the oldest slice of Earth we know.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT