Is Big Bang finding wrong?

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.

Planetary nebula Abell 33 appears ring-like in this image, taken using the European Southern Observatory's Very Large Telescope. The blue bubble was created when an aging star shed its outer layers and a star in the foreground happened to align with it to create a "diamond engagement ring" effect.

This long-exposure image from the Hubble Telescope is the deepest-ever picture taken of a cluster of galaxies. The cluster, called Abell 2744, contains several hundred galaxies as they looked 3.5 billion years ago; the more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang.

NASA's NuSTAR telescope array generated the first map of radioactivity in the remnants of an exploding star, or supernova. Blue in this image of Cassiopeia A represents radioactive material.

A supernova was spotted on January 21 in Messier 82, one of the nearest big galaxies. This wide view image was taken on January 22.

The M82 supernova, seen here, has been designated SN2014J because it is the 10th supernova detected in 2014. At 11.4 million light years from Earth, it is the closest Type Ia supernova recorded since systematic studies with telescopes began in the 1930s.

Is that a giant hand waving at us? Actually, it's what's left of a star that died and exploded a long time ago. Astronomers nicknamed it the "Hand of God." NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, took this image in high-energy X-rays, shown in blue. The image was combined with images from another space telescope, the Chandra X-ray Observatory.

The Hubble Space Telescope captured this image of the Southern Pinwheel Galaxy, one of the largest and closest galaxies of its kind. The center of the galaxy is mysterious, researchers say, because it has a double nucleus -- a supermassive black hole that may be ringed by a lopsided disc of stars, giving it the appearance of a dual core.

Hubble scientists say this is the best-ever view of the Tarantula Nebula, which is located in one of our closest galactic neighbors, the Large Magellanic Cloud.

Those spots on our sun appear small, but even a moderate-sized spot is about as big as Earth. They occur when strong magnetic fields poke through the sun's surface and let the area cool in comparison to the surrounding area.

This Hubble image looks a floating marble or a maybe a giant, disembodied eye. But it's actually a nebula with a giant star at its center. Scientists think the star used to be 20 times more massive than our sun, but it's dying and is destined to go supernova.

• 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.

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.

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.

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