Skip to main content

Big Bang breakthrough announced; gravitational waves detected

STORY HIGHLIGHTS
  • Gravitational waves were predicted by Albert Einstein
  • New results from BICEP2 are 'smoking gun for inflation'
  • During inflation, the universe expanded faster than the speed of light

(CNN) -- There's no way for us to know exactly what happened some 13.8 billion years ago, when our universe burst onto the scene. But scientists announced Monday a breakthrough in understanding how our world as we know it came to be.

If the discovery holds up to scrutiny, it's evidence of how the universe rapidly expanded less than a trillionth of a second after the Big Bang.

"It teaches us something crucial about how our universe began," said Sean Carroll, a physicist at California Institute of Technology, who was not involved in the study. "It's an amazing achievement that we humans, doing science systematically for just a few hundred years, can extend our understanding that far."

What's more, researchers discovered direct evidence for the first time of what Albert Einstein predicted in his general theory of relativity: Gravitational waves.

These are essentially ripples in space-time, which have been thought of as the "first tremors of the Big Bang," according to the Harvard-Smithsonian Center for Astrophysics.

A telescope at the South Pole called BICEP2 -- Background Imaging of Cosmic Extragalactic Polarization 2 -- was critical to the discovery. The telescope allowed scientists to analyze the polarization of light left over from the early universe, leading to Monday's landmark announcement.

The BICEP2 telescope looks at polarization of light from 380,000 years after the Big Bang.
The BICEP2 telescope looks at polarization of light from 380,000 years after the Big Bang.

How inflation works

Scientists use the word "inflation" to describe how the universe rapidly expanded after the Big Bang in a ripping-apart of space. The BICEP2 results are the "smoking gun for inflation," Marc Kamionkowski, professor of physics and astronomy, said at a news conference. Kamionkowski also was not involved in the project.

"Inflation is the theory about the 'bang' of Big Bang," said Chao-Lin Kuo, an assistant professor of physics at Stanford and SLAC National Accelerator Laboratory, and a co-leader of the BICEP2 collaboration, in a Stanford video. "It explains why we have all this stuff in the universe."

Imagine that you are making a raisin bun, said Stanford physicist Kent Irwin, who worked on sensors and readout systems used in the experiment. As the dough bakes and expands, the distance from any given raisin to another increases.

"Certainly everything in the universe that we see now, at one time before inflation, was smaller than an electron," Irwin said. "And then it expanded during inflation at faster than the speed of light."

You may have learned in physics class that light sets the universe's speed limit, but space-time is an exception; it can stretch faster than the speed of light, Irwin said.

Stanford University professor Andrei Linde, who helped develop the current inflation theory, said the new results are something he had hoped to see for 30 years.

"If this is true, this is a moment of understanding of nature of such a magnitude that it just overwhelms and let's just hope that it's not a trick," Linde said in a university video interview.

Another cool tidbit: Inflation can be used in theories that suggest the existence of multiple universes, Irwin said, although these results do not directly address such theories.

What are gravitational waves?

Scientists believe that in the fabric of space-time, there are tiny ripples called quantum fluctuations. If you could look at space-time on the smallest scale possible, you would, in theory, see them, even today. Unfortunately, no microscope is capable of seeing something that small.

Such fluctuations also existed at the beginning of the universe. Inflation blew them up much larger, launching gravitational waves that we now see imprinted on the cosmic microwave background. "These gravitational waves are an aftershock of the Big Bang," he said. The BICEP2 study is the first to image them directly.

"We have for the first time a detection for the mythical gravity wave signal that people have been searching for so hard, for so long," said Clem Pryke, associate professor at the University of Minnesota, at a press conference Monday.

Other experiments such as LIGO -- Caltech's Laser Interferometer Gravitational Wave Observatory -- are also looking for proof of gravitational waves, but in the context of energetic cosmic phenomena such as coalescing black holes.

The gravitational waves suggested by the BICEP2 results would have expanded across the entire universe at that time, Irwin said. The length of one of these waves -- the distance between peaks and troughs -- would have been billions of light years across.

Light from the early universe, called cosmic microwave background radiation, reveals these telltale signs of our universe's history. Last year, scientists from the European Space Agency's Planck space telescope released a detailed map of temperature variations in this light, which came from from about 380,000 years after the Big Bang.

Better 'baby picture' of universe emerges

Instead of temperature, BICEP2 scientists were looking specifically at the polarization of the cosmic microwave background -- that is, the direction the electric field is pointing across the sky.

Researchers were looking for a specific type of polarization called "B-modes," which signify a curling pattern in the polarized orientations of light from the ancient universe, said Jamie Bock, co-leader of the BICEP2 collaboration and professor of physics at California Institute of Technology.

In theory, this swirling polarization pattern could only be created from gravitational waves. And that is what BICEP2 found.

"It's a very clean signature of those gravity waves," Irwin said.

Is it for real?

Because of how potentially important these results are, they must be viewed with skepticism, said David Spergel, professor of astrophysics at Princeton University. The measurement is a very difficult one to make and could easily be contaminated. There are, as it stands, some "oddities" in the results that could be concerning, he said.

"I am looking forward to seeing these results confirmed or refuted by other experiments in the next year or two," Spergel said.

The Planck space telescope collaboration is expected to release results on polarization of the cosmic microwave background as well, Irwin said. Other experiments are working toward similar goals, which could support or go against BICEP2.

Regardless, Monday's announcement is making big waves in the scientific community.

Follow Elizabeth Landau on Twitter at @lizlandau

ADVERTISEMENT
Part of complete coverage on
Science news
August 25, 2014 -- Updated 1934 GMT (0334 HKT)
Nichelle Nichols has spent her whole life going where no one has gone before, and at 81 she's still as sassy and straight-talking as you'd expect from an interstellar explorer.
July 22, 2014 -- Updated 1152 GMT (1952 HKT)
The world's largest flying aquatic insect, with huge, nightmarish pincers, has been discovered in China's Sichuan province.
June 23, 2014 -- Updated 1210 GMT (2010 HKT)
As fans of "Grey's Anatomy," "ER" and any other hospital-based show can tell you, emergency-room doctors are fighting against time.
May 29, 2014 -- Updated 1159 GMT (1959 HKT)
Ask 100 robotics scientists why they're inspired to create modern-day automatons and you may get 100 different answers.
June 13, 2014 -- Updated 1635 GMT (0035 HKT)
From the air, the Namibian desert looks like it has a bad case of chicken pox.
May 28, 2014 -- Updated 1643 GMT (0043 HKT)
The trend for nature-inspired designs has spread across industries from crab-style deep-sea vessels to insect-inspired buildings.
May 25, 2014 -- Updated 1222 GMT (2022 HKT)
Consider it the taxonomist's equivalent of a People magazine's Most Beautiful List.
May 9, 2014 -- Updated 1532 GMT (2332 HKT)
For the first time, scientists have shown it is possible to alter the biological alphabet and still have a living organism that passes on the genetic information.
May 5, 2014 -- Updated 1148 GMT (1948 HKT)
Do we really want to go the route of "Jurassic Park"?
May 2, 2014 -- Updated 1244 GMT (2044 HKT)
Catch a train from the sky! Perhaps in the future, the high-rise superstructures could help revolutionize the way we travel.
May 5, 2014 -- Updated 1458 GMT (2258 HKT)
In a nondescript hotel ballroom last month at the South by Southwest Interactive festival, Andras Forgacs offered a rare glimpse at the sci-fi future of food.
March 20, 2014 -- Updated 1412 GMT (2212 HKT)
For a Tyrannosaurus rex looking for a snack, nothing might have tasted quite like the "chicken from hell."
March 14, 2014 -- Updated 2229 GMT (0629 HKT)
Everyone is familiar with Tyrannosaurus rex, but humanity is only now meeting its much smaller Arctic cousin.
March 6, 2014 -- Updated 1712 GMT (0112 HKT)
At about 33 feet long, weighing 4 to 5 tons and baring large blade-shaped teeth, the dinosaur Torvosaurus gurneyi was a formidable creature.
February 21, 2014 -- Updated 1143 GMT (1943 HKT)
This Pachyrhinosaurus can go to the head of its class.
March 27, 2014 -- Updated 1204 GMT (2004 HKT)
Science is still trying to work out how exactly we reason through moral problems, and how we judge others on the morality of their actions. But patterns are emerging.
February 28, 2014 -- Updated 0006 GMT (0806 HKT)
A promising way to stop a deadly disease, or an uncomfortable step toward what one leading ethicist called eugenics?
February 15, 2014 -- Updated 0107 GMT (0907 HKT)
Seattle paleontologists safely removed the largest fossilized mammoth tusk discovered in the region from a construction site.
April 23, 2013 -- Updated 1013 GMT (1813 HKT)
A mysterious, circular structure, with a diameter greater than the length of a Boeing 747 jet, has been discovered submerged about 30 feet underneath the Sea of Galilee in Israel.
January 17, 2014 -- Updated 2225 GMT (0625 HKT)
Every corner of the planet offers some sort of natural peculiarity with an explanation that makes us wish we'd studied harder in junior high Earth science class.
November 14, 2013 -- Updated 1320 GMT (2120 HKT)
Deep in a remote, hot, dry patch of northwestern Australia lies one of the earliest detectable signs of life on the planet, tracing back nearly 3.5 billion years, scientists say.
September 4, 2013 -- Updated 1910 GMT (0310 HKT)
We leave genetic traces of ourselves wherever we go -- in a strand of hair left on the subway or in saliva on the side of a glass at a cafe.
ADVERTISEMENT