Can studying the ‘inhuman universe’ make us more humane?

Black holes form when a star dies, or do they? Cosmologist Dr Syksy Räsänen says solving fundamental questions about the universe helps us better understand our own place in it.

“It’s a very inhuman universe,” says Dr Syksy Räsänen, a theoretical physicist and cosmologist at the University of Helsinki.

For Räsänen, studying the formation and expansion of the universe gives you a different perspective on life’s issues.

“I think it makes it easier, this sort of detachment that you get in physics, because the things that you study are so far from any human concerns.”

It allows you to perhaps view things more clearly, he says.

Räsänen, who has worked at CERN in Switzerland, the University of Oxford in the UK, Kobe University in Japan, Birzeit University in Palestine, and elsewhere, was in Dublin last week to give a talk as part of the Dublin Institute for Advanced Studies (DIAS) Samhain and Science festival.

‘Spooky’ black holes

His talk was on the “spooky” topic of primordial black holes. “Black holes are born when stars die [but] for some early very massive black holes, we’re not sure how they were formed,” Räsänen says.

This problem was realised about 30 years ago but new observations from the James Webb Space Telescope have brought it to the fore.

The James Webb, which was launched in 2021, has observed that there were massive black holes (“like a billion solar masses”) at very early times.

It’s difficult to understand, Räsänen says, if you start from stellar collapse, how these massive black holes got so big in the very early universe.

“One possibility and there are different ideas … is that they are created on seeds that are made at very early times.”

He wonders “whether the seeds for these black holes, so these big clumps of matter in the early universe, could be produced by a process called cosmic inflation, which is a period in the early universe where the seeds of the structures that we know [such as] galaxies and planets are formed”.

Cosmic inflation is a theory developed in the 1980s that around 13.8bn years ago the universe expanded faster than the speed of light for a fraction of second.

NASA infographic outlining the theory of the history of the universe. Image: NASA

“The early universe is very uniform and then you have these tiny inhomogeneities, so somewhere there is a bit more mass, you know, then it accretes more mass and then it accretes even more mass. And then you form a galaxy,” Räsänen says.

“You just have these little changes and the way you treat that usually in inflation is that you just treat the evolution of these small inhomogeneities independently of the overall background, because they’re small, you really don’t care.

“But to form black holes, you need very large inhomogeneities – black holes are very extreme objects.”

Räsänen works with collaborators Dani Figueroa, Sami Raatikainen and Eemeli Tomberg to develop the first code that takes into account the effect of these large inhomogeneities on the mean expansion of the universe and the effect of the mean expansion on them simultaneously, among other things. And the result is a change in the estimated number of black holes that were formed.

Räsänen’s research involves a lot of numerical and analytical work to theorise solutions to this question.

“Basically, what we are aiming for is to have a reliable assessment that if you have some sort of model for what goes on in the early universe, what is this theory of cosmic inflation, what’s happened, that given this model, you can reliably calculate the abundance of primordial black holes.”

But why?

A question Räsänen often gets asked is why study these phenomena? Why should we care?

One answer, he says, is that you never know what spin-offs there will be.

“You know practically all modern technology today is based on quantum mechanics,” he says.

Quantum mechanics was discovered by investigating basic academic questions such as why when you heat up hydrogen gas, do you get light only at certain wavelengths? (He finds it funny that ‘academic’ also means irrelevant).

“So, you never know where things are going to lead,” he says.

“But at the same time, if you’re honest, you have to say, we shouldn’t promise that cosmology will give us some technological breakthroughs.

“We should fund it because what we can say is that it will continue to give us insights about fundamental issues, so the fundamental laws of the universe, the evolution of the universe and understanding our place in the universe differently.”

A responsibility to communicate

Räsänen’s work is complex and highly technical, but he sees it as a kind of responsibility to explain his research and the wider field of cosmology to the public.

“I think this is a responsibility of the scientific community to tell the public, who ultimately are the ones who are mostly funding this work, to tell them what we have found.” Though he doesn’t think every scientist should have to do this.

He drifted into scientific outreach because one of his PhD supervisors, who is famous in Finland for popularising science, encouraged it.

“One obvious benefit is that when you write for the public, you have to use effort to express things clearly and understandably, which means that you have to really think about what you’re saying.”

This helps him to “process and understand things in a different way”, Räsänen says.

Another benefit of outreach is that you have to put yourself in the shoes of the listener and try to understand what they know and don’t know, which encourages you to look at the work “from the outside”, he says.

“This then gives you a different perspective on what you’re doing and can sort of help you to evaluate in a different way.

“So, it’s not useful for the content of research. It’s not that you’re getting great ideas from audience questions or whatever, but it helps you to understand what you’re doing in a different way.”

This idea of seeing from different perspectives recurs when talking to Räsänen. It is something he embodies in his role as a science communicator and as a cosmologist, but also as an activist. For many years, he has been an outspoken advocate for Palestine and the rights of Palestinians.

And while he doesn’t see a huge overlap in his academic work and his activism, this outsider perspective, this seeing from different angles helps him look at issues as part of the bigger picture, he says.

He gives the example of Albert Einstein, who was very outspoke on social issues in the US and this fits, Räsänen says, with his genius for looking at scientific problems “from the outside”.

“So, then this realisation and this perspective also helps you to be, how would I say, less tribal and, you know, less attached to prejudices which we inevitably always have when it comes to social affairs or human affairs.”

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