UNC physicist notes problem with existence of black holes

Laura Mersini-Houghton was among the international physicists who gathered in Stockholm, Sweden, to sort out the tangle of theories about black holes.
Laura Mersini-Houghton was among the international physicists who gathered in Stockholm, Sweden, to sort out the tangle of theories about black holes. UNC-Chapel Hill

Laura Mersini-Houghton, a theoretical physicist and cosmologist at UNC-Chapel Hill, made headlines several years ago with her predictions related to the multiverse theory – the idea that our universe is one of many. Now she’s back in the news casting doubt on the existence of black holes.

Cosmologists interested in black holes have long struggled with the paradox of the “information loss problem.” According to Einstein’s theory of gravity, nothing can escape the gravitational pull of a black hole. However, using quantum mechanics, Stephen Hawking proposed that black holes emit quantum radiation. Mersini-Houghton says, “You can either have black holes or quantum radiation, but not both.” Her calculations show that a collapsing star stops just short of creating the spot of infinite density that makes a black hole a black hole.

In late August, Mersini-Houghton was among the international physicists who gathered in Stockholm to sort out the tangle of theories. In fact, she organized the conference. In an interview this fall, she talked about the gathering – and how it went.

Q. The weeklong conference of physicists in Stockholm, including Stephen Hawking, discussed the “information loss problem” related to black holes. Why did you want everyone in one room?

A. If there is a solution to this problem, our chances of pushing progress are much higher if we collect all the brainpower in one room. The conference focused on discarding anything that’s been tried and tested and doesn’t work. It zoomed into a handful of promising solutions – there was one from Hawking and one from Gerard ‘t Hooft, a Nobel Prize winner.

Q. What was the atmosphere at the conference? Was there a lot of arguing?

A. What to us is passionate debating to an outsider might look like vicious fighting. Everyone was exhausted but it was clear we all loved it.

Q. Science writer James Gleick once wrote, “Theorists conduct experiments with their brains.” As a theoretical physicist, how do you approach a scientific problem?

A. Normally I spend a lot of time thinking about the problem. Has it been done before? What did people try and fail, and why did it fail? Once that is done, it will be playing devil’s advocate with myself, turning an idea over in my mind and all the possible things that can go wrong with it. When I have convinced myself I can’t find anything wrong with it, then I’ll sit down and do the calculations.

Q. Do you do all your work at a desk?

A. I walk a lot when I’m stuck with something. I need to fight with it and struggle with it. I’ll go for long walks and try to turn it in my head. Somehow walking helps me think faster. But otherwise, it’s almost like the right time and the right place. With the origin of the universe, I was in Starbucks staring into space.

Q. Why is it important to figure out the origin of the universe?

A. It’s what makes us human. This is our home, and since the cavemen until the present day, we’ve always looked up in the sky and wondered where this all came from. We have a brain so we can ask those questions; that’s what makes our lives worth living.

On the economic side, as a theoretical physicist, how something might be applied is the last thing on my mind. But this is the century of science. Absolutely everything we do from telephones to computers to driving is based on some scientific discovery, although the application is not always immediately clear at the time of discovery. Without that inquiry and curiosity to understand the world around us, we would never have moved forward as a human species.

Q. You grew up in Albania. What was that like?

A. It’s a combination of very good things and very bad things. It was a communist country. My dad was a mathematician; he worked in applied math in economics. He came from a rich, title-bearing family before communism, and his whole extended family was considered enemies of the state. He was sent into exile three times. My mother worked at the National League of Writers and Artists. I had this privilege of science on one side and writer-artists on the other, and as an only child for nine years, there was all this attention on my education and upbringing. When my dad would come home from work, he would talk to me since I was 3 or 4 years old about whatever problem he was working on.