When you hear about the Big Bang, what do you think? Do you worry about having missed last night’s episode of The Big Bang Theory? Well, then you must have had quite a week given that the cosmological event was mentioned everywhere you turned. Last week, a team of researchers from Harvard University called the BICEP2 collaboration published what they consider to be observational evidence of an important post-Big-Bang phenomenon.
News outlets across the world celebrated the accomplishments of the BICEP team. The team of researchers, led by John Kovac, successfully observed spiral patterns that are visual evidence for gravitational waves and the theory that the universe expanded rapidly just after the Big Bang, according to their published results.
Boston University professors hailed the findings as a major accomplishment for the field and as a clearer sign of our cosmic origins.
“My take on this announcement is that if it is confirmed, this is the most exciting thing to happen in cosmology in at least 15 years,” said professor Tereasa Brainerd, who is also chair of the astronomy department. “I think it’s really fair to say that … we have learned something new about the universe that our theories predicted ought to be there, and it appears that the observations are now telling us that the theory is correct.”
Using a set of high-powered radio telescopes located at the South Pole, the researchers surveyed the sky to observe some of the oldest light in the universe, known as the cosmic microwave background — in other words, the dim afterglow of the Big Bang.
Since this background radiation has all the properties of light, it can be polarized like light, and the researchers concluded that this is evidence that the universe dramatically expanded after the Big Bang, referred to as “inflation.”
“[The theory of inflation] was proposed back in the early 1980s to explain why if you looked in one direction and another direction at very great distances why the universe seems to be the same,” said Alan Marscher, director of the Institute for Astrophysical Research at BU. “… The idea was that what was once a very small region where it got easily mixed up then expanded greatly, and then it took all that uniform mixture and expanded it.”
Scientists have published what they consider to be empirical, observational evidence that just after the Big Bang the universe expanded from a speck smaller than a subatomic particle to something close to the size of what it is today, all in less time than you can possibly imagine (from 10-36 seconds to 10-32 seconds). To do this, it exploded outward faster than the speed of light.
Such a violent rend sent ripples of gravitational waves through the fabric of spacetime, and as the universe expanded over time, the ripples stretched out. Imagine slowly spreading out a wrinkled towel for comparison. These ripples produced a distinct spiral pattern on light by polarizing it, and this pattern is what researchers observed in the BICEP experiment.
“One of the things we know about this light [from the cosmic microwave background radiation] is that the temperature is the same, almost perfectly, over the entire sky,” Brainerd said. “And it turns out that’s a hard thing to understand, because on very large scales of the present day, the universe shouldn’t have necessarily been as uniform a temperature. So inflation as a theory actually explains all of those observations.”
Both Brainerd and Marscher said they would be certain to include these findings into their classes on astronomy, though they admitted it may be difficult to present the information in an accessible manner.
“I wrote a book called From Nothing to Everything and so I’ve got to revise this because it talks a little bit about … the cosmic microwave background pattern,” Marscher said. “… The pattern can be graphed and charts consistent with what was predicted by inflation — now I’ve got to add another figure about the polarization pattern that was observed and explain why there was a different polarization pattern that was predicted.”
Brainerd said this discovery validates much of the day-to-day, often draining work that comes with scientific research.
“I think as a scientist most of what you do day-by-day can be drudgery,” she said. “Every day, we go to work and we try to make small progress in science, and I think one of the things that helps all of us remain excited about our careers and excited about being scientists is when you see really major results. Those things don’t come along more often than 10 to 20 years and this is a biggie — this is really a biggie — so … this is just tremendously exciting for the field.”