By Katdie Norton
Scientists have ridden gravitational waves to understand the Big Bang better.
A group of scientists discovered on March 17 more evidence favoring the Big Bang Theory and also supporting a theory posed in the 1980s called inflation.
“Primordial gravitational waves (PGWs) were created around 10-36 seconds after the Big Bang — the earliest signs so far that we can see,” said, Dr. Anzhong Wang, a professor in the physics department.
Wang said 10-36 seconds is about a trillionth of a trillionth of a trillionth of a second, and in that time, our universe expanded exponentially.
These PGWs were measured by Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2), a telescope mounted at the South Pole.
“What BICEP2 observed are the imprints of PGWs on the CMB,” Wang said.
According to Wang, the Cosmic Microwave Background was formed 380,000 years after the Big Bang, and until now, this was as far back that scientists could see. These PGWs seen by the BICEP2 telescope are an imprint, similar to an image being burned into a screen.
What exactly does this prove?
Dr. Gerald Cleaver, a professor of physics, said before the Big Bang, photons (light particles) were traveling back and forth between positively charged nuclei and negatively charged electrons within a millimeter of space. Then the overall temperature of that tiny space lowered enough that the positive and negative particles formed together into whole atoms.
When the atoms were created, the photons were freed from their millimeter of space and they carried with them the effects that gravity had on them while they were confined.
Within less than a trillionth of a second from a millimeter of space, the universe expanded and the photons’ gravitational waves left their imprint.
This exponentially rapid expansion of the universe is inflation.
Cleaver said the gravitational waves are assumed to have had an effect on the polarization of the light particles that escaped and this is what BICEP2 captured and analyzed.
“The polarization isn’t the direction the photons are moving,” Cleaver said. “It’s the direction of the electric field of the photons.”
Cleaver said photons move throughout space because they are creating both an electric field and a magnetic field at the same time, and this moves them in straight lines called E-Modes, which is not what BICEP2 found.
According to BICEP2’s release papers, gravitational waves from inflation generate a faint but distinctive twisting pattern in the polarization of the CMB, known as a “curl” or B-mode pattern. This B-mode pattern is what the satellite captured.
Cleaver said this discovery might also prove that if our universe can expand like this, other universes beyond ours might have as well.
“The probability of having the conditions to produce [inflation] for one universe is small if you assume that is the only universe that it happened to,” Cleaver said. “Now that we have evidence of inflation of our universe that really implies that there is some much more fundamental area of space time out of which universes inflate in a vast uncountable number.”
Cleaver said the best example is boiling water where the water is space time and the bubbles are universes. The bubbles continue to pop up everywhere and inflate like ours.
What happens next?
All new scientific discoveries fall under scrutiny and have to be proven by another source as well, and the discovery of the PGWs is no different.
“Further confirmations are needed,” Wang said. “Because there are two other main sources produce B-Modes: galaxies and dust among space.”
Wang said between the CMB and Earth are galaxies and space dust that, when you look through them, could distort the way the gravitational waves look, just like looking at something through water.
“BICEP2 claimed that what they observed cannot be explained by the galaxies or dust,” Wang said.
In 2009, the European Space Agency launched a satellite called Planck to gather data, some of which could disprove or confirm this discovery.
Although the original date for the release of this data was set for March, the world has to wait until July to find out whether or not the discovery of the B-Mode Primordial Gravitational Waves is proven.
If this is proven then Wang, Cleaver and a host of other scientists, current and future, from Baylor and all over the world will have plenty of work ahead of them.