{"id":27996,"date":"2019-01-16T09:27:32","date_gmt":"2019-01-16T14:27:32","guid":{"rendered":"https:\/\/college.unc.edu\/?p=27996"},"modified":"2019-01-16T09:27:32","modified_gmt":"2019-01-16T14:27:32","slug":"an-origin-story","status":"publish","type":"post","link":"https:\/\/collegearchive.unc.edu\/?p=27996","title":{"rendered":"An Origin Story"},"content":{"rendered":"

Most theoretical physicists don\u2019t see their predictions confirmed in their lifetimes, as it can take centuries to discover the physical phenomena that marks them true. But that hasn\u2019t been the case for UNC\u2019s Laura Mersini-Houghton, who\u2019s seen six of her predictions about the origins of the universe verified in the last decade \u2014 a feat that\u2019s grabbed everyone\u2019s attention, from documentary filmmakers to the late Stephen Hawking.<\/em><\/p>\n

\"Laura<\/p>\n

On the northern tip of Ireland, where the North Sea meets the Atlantic, waves smash into 40,000 ancient, hexagon-shaped pillars at Giant\u2019s Causeway \u2014 the result of a volcanic eruption 60 million years ago. Small pools form in the cracks between each column. As the winds rage, the sun scorches the landscape, and a bone-chilling sweat settles over Laura Mersini-Houghton<\/a>, who shifts uncomfortably. Across from her, a documentary filmmaker stands behind a video camera and asks her a question. She tries not to shiver as she replies.<\/p>\n

\u201cThink of these waves leaping over the rocks as the wave function of the universe trying to travel through this landscape structure. If I think of the rocks as the energy field and each pocket representing an energy valley on the landscape, as the waves come through, many will be trapped in different pockets rather than travel further. Each pocket can be a birthplace for a universe similar to ours.\u201d<\/p>\n

Mersini-Houghton is explaining the multiverse hypothesis. First suggested by the Ancient Greek philosopher Democritus, it is the idea that our universe is one of many formed by a Big Bang-like event \u2014 a concept that Mersini-Houghton agrees with. A UNC cosmologist and pioneering theoretical physicist, she began studying the origin of the universe decades ago. Why? Because the probability that our universe should even exist is basically zero, according to Mersini-Houghton. \u201cThe chances are 1 in 10 with 123 zeroes behind it, so pretty much zero.\u201d<\/p>\n

In 2005, Mersini-Houghton had a curious idea. A frequenter of coffee shops, she sat in quiet contemplation at the Starbucks on Franklin Street, staring thoughtfully at her pen and pad on the table. She began to think about the mathematical representation of the universe, which forms a wave, and spent hours lost in thought over it.<\/p>\n

Then something clicked: What if she combined the physics of string theory (the idea that matter and energy are composed of tiny, vibrating strings) with those of quantum mechanics (how matter and light behave at microscopic levels)? She used the former to manipulate the wave, and after calculating how that waveform evolves, she found that the result is many universes \u2014 each with their own properties and constants \u2014 and one high-energy Big Bang. To the average mind, the process sounds complex, but to Mersini-Houghton, \u201cit\u2019s so simple that it\u2019s too simple,\u201d she chuckles.<\/p>\n

After taking more time to work out the problem, Mersini-Houghton developed her first calculation for the origin of the universe<\/a>. \u201cWe got the correct answer theoretically for the first time in science,\u201d she says. \u201cBefore then, we hadn\u2019t been able to derive an answer to the origin of the universe. That gave me hope to check for predictions to test that theory. But getting the right answer does not guarantee what nature does. What does nature care about some theory I cooked up?\u201d<\/p>\n

Although Mersini-Houghton is not the first person to support a multiverse hypothesis, she is the first to successfully derive the answer from basic physics principles and <\/em>live in a time when there\u2019s physical observations that support it.<\/p>\n

\"blackboard
From a mathematical perspective, this is Mersini-Houghton\u2019s calculation for the origin of the universe.<\/figcaption><\/figure>\n

The same sky<\/strong><\/p>\n

If other universes exist, then those closest to our own would exert a gravitational tug, causing matter to shift. Think of it like a piece of fabric. Pull on it from both sides and it begins to stretch. Continue tugging on it and, over time, a hole forms. For Mersini-Houghton, this meant that, somewhere in our universe, there should be a void. A big one.<\/p>\n

\u201cThe sky we observe today is just a blown up version of the sky from 14 billion years ago,\u201d she explains. \u201cSo whatever happened in the universe\u2019s infancy \u2014 it\u2019s still there somewhere in our sky. And we can track it down.\u201d<\/p>\n

In August 2007, University of Minnesota physicist Lawrence Rudnick did just that \u2014 accidentally. While studying data from the NRAO VLA Sky Survey, he discovered an abysmal hole, nearly a billion light-years across, containing virtually no matter. And it was located in the region Mersini-Houghton and her collaborators first predicted it would be in 2006<\/a>.<\/p>\n

\u201cWe got lucky,\u201d she admits. \u201cIt was first observed accidentally only seven months after we predicted it. It caused huge fights in the astrophysics community about whether those observations were correct or not.\u201d<\/p>\n

Data from the Wilkinson Microwave Anisotropy Probe<\/a> (WMAP) satellite helped verify the void\u2019s presence. The satellite measures temperature fluctuations throughout the universe, and the hole\u2019s location runs cold. But it wasn\u2019t until 2015, after using a more precise satellite called Planck<\/em>, when the cold spot\u2019s existence was officially recognized and confirmed.<\/p>\n

\u201cI was in the right place at the right time,\u201d Mersini-Houghton says. \u201cWhen I was working on these predictions I thought we would not have these observations in my lifetime. They\u2019re challenging our understanding of the universe \u2014 and we cannot brush them under the rug.\u201d<\/p>\n

What Mersini-Houghton calls luck has drastically propelled her career forward. She\u2019s since been tenured and is regularly sought after as an expert in her field, with appearances in a variety of documentaries including the BBC\u2019s \u201cWhat Happened Before the Big Bang\u201d (2010) and \u201cWhich Universe Are We In?\u201d (2015), as well as the Science Channel\u2019s \u201cThrough the Wormhole with Morgan Freeman\u201d (2011).<\/p>\n

Into the void<\/strong><\/p>\n

After spending 10 years tweaking her multiverse hypothesis, Mersini-Houghton shifted her attention to a popular topic of debate in the physics world: black holes. \u201cEven today, nobody understands what happens inside a collapsing star that is about to become a black hole \u2014 especially in quantum mechanical terms,\u201d she says.<\/p>\n

Problems often arise here due to conflicting theories. Einstein\u2019s theory of gravity suggests that the gravitational attraction of a black hole is so powerful that not even light can escape its grasp. But a fundamental law of quantum theory states that no information from the universe can ever disappear. And in 1974, Stephen Hawking first argued that black holes do emit<\/em> a type of radiation that reduces the mass and energy of the hole. Today this is called Hawking radiation.<\/p>\n

\u201cBut in order to have a consistent study, we need to incorporate both theories simultaneously,\u201d Mersini-Houghton says. Physicists who tried to combine the two theories in the past were left with a mathematical mess called the information loss paradox.<\/p>\n

In 2014, Mersini-Houghton developed a novel numerical solution<\/a> to the problem, suggesting that as a star sheds radiation it also sheds mass \u2014 a process that stops the formation of singularities in the center of black holes. Singularities are one-dimensional points containing a huge mass in an infinitely small space, and they continue to vex scientists because the laws of physics cease to operate where they exist.<\/p>\n

\u201cThey are thought as holes that pinch the fabric of space time in our universe and give rise to many speculations,\u201d Mersini-Houghton says. \u201cBut we don\u2019t yet know if singularities can be physically found at the center of a black hole.\u201d<\/p>\n

Does that mean black holes don\u2019t exist? No, it means that quantum effects can prevent the formation of a singularity at the center of the black hole.<\/p>\n

\u201cIt\u2019s a difficult problem,\u201d Mersini-Houghton stresses. \u201cAnd I wasn\u2019t completely happy with my model, which made a lot of approximations. So I decided to call the founding fathers in Stockholm and hold a conference.\u201d<\/p>\n

Collective wisdom<\/strong><\/p>\n

In 2015, in a small conference room at the KTH Royal Institute of Technology, a university in Stockholm, Sweden, a group of scientists gathered around four rows of tables, engaged in animated discussion. Some sat patiently. Some paced around the room. Others threw their hands up in frustration.<\/p>\n

\u201cWhat, to us, is passionate debating, to an outsider might look like vicious fighting,\u201d Mersini-Houghton once told a reporter from the News & Observer<\/em><\/a>. <\/em><\/p>\n

This is how the world\u2019s most renowned theoretical physicists work to uncover the unknowns of the universe. In August 2015, Mersini-Houghton<\/a> brought 31 of them together<\/a> \u2014 with help from UNC Chancellor Carol Folt, then-Provost Ron Strauss, and College of Arts & Sciences Dean Kevin Guskiewicz \u2014 to discuss black holes.<\/p>\n