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In an interview with APS News, Kolb discusses the Big Bang, parallel universes, and the need for public outreach.
By Liz Boatman
Credit: Jason Smith
Edward “Rocky” Kolb
What’s outside the universe? What came before the Big Bang? Does life exist elsewhere, and if so, would we recognize it? These are the questions that excite cosmologist Edward “Rocky” Kolb.
Kolb, the Arthur Holly Compton Distinguished Service Professor of Astronomy and Astrophysics at the University of Chicago and an APS Fellow, is the recipient of the 2024 Julius Edgar Lilienfeld Prize. The prize recognizes physicists who’ve made “outstanding contributions” to physics and who excel in communicating with diverse audiences.
The recognition matters, says Kolb, because he can recall a time when cosmology — the branch of physics focused on the origin and development of the universe — wasn’t a “respectable” field of scientific inquiry.
When he entered the field in the late 1970s, cosmologists were mostly working with theory. “People felt it was more like a religion or metaphysics,” he says. “Today, though, cosmologists perform observations and carry out experiments just like other physicists. They’ve even won the Nobel Prize.”
Kolb is a member of the Enrico Fermi Institute and the Kavli Institute for Cosmological Physics. He has contributed to more than 230 scholarly publications, co-authored multiple books, and taught countless courses, including some for non-physics majors and adults who enroll in the university’s extension program — his favorite courses to teach.
Kolb is particularly passionate about public outreach. “It validates for postdocs and grad students that it’s a good thing for them to do,” he says. His passion is inspired in part by the late Leon Lederman, a Nobel Prize-winning particle physicist who Kolb says led by example, encouraging Kolb’s own outreach work in his early career.
Kolb spoke with APS News about his views on the universe and the importance of public engagement.
This interview has been edited for length and clarity.
What about the early universe captivates you?
It's the origin of everything, and it entailed conditions of temperature and pressure and density that we cannot reproduce here on Earth. So if we ask questions about the nature of matter at extreme temperatures or extreme energies beyond those which we can reproduce in laboratories, then we can look to the early universe as our ‘particle accelerator’ — a type of experimental facility that physicists might use to answer those types of questions. It’s comparatively cheap because the experiment has been done — the Big Bang already happened. We just have to understand the results of the experiment by looking back in time to develop our understanding of the early universe.
How did you enter the field cosmology, and how has it changed?
I stumbled into cosmology, as a particle theorist. How we view the field of cosmology has been a really big change over the course of my career — that a field that was once looked down upon is now at the forefront of so much activity. Today, cosmology is bridging the gap between the ‘inner space’ of quantum physics and the fundamental laws of physics with ‘outer space’ — the cosmos. Those connections didn’t exist when I first entered the field, but now we recognize that we can learn something about fundamental physics from studying the universe, and we can learn something about the universe from studying fundamental physics.
A good example of this is ’dark matter.’ We still don't know what most of the matter of the universe is made of. We believe it's a particle beyond the standard model of particle physics, which we call ‘dark matter.’ Even though we still don’t know the true nature of dark matter, it represents a connection between the inner space and outer space that is yet to be discovered.
On your website, you list the “top 10 questions about the universe” that still need to be answered. Let’s get your thoughts on a few of them. What came before the Big Bang?
There was nothing before the Big Bang. Not only was there no matter or galaxies or radiation, there was no space and no time. So, if there was no time, perhaps the question doesn’t make sense. How can ‘before’ make sense if time did not exist? The Big Bang was time equal to zero and the origin of everything in the universe, including space and time.
What’s outside the universe?
When I give a public lecture, I can predict that invariably either this question will come up or a question about the Big Bang. It’s really difficult to get these concepts across, even in a graduate course on cosmology — but there is no ‘outside’ the universe.
Is there a parallel universe?
The idea of a parallel universe is mixed up with the idea of a multiverse, which is an idea that's come up in the past 20 years or so, driven by the theory of cosmic inflation — that what we call the universe, the vastness of space that we see as just one universe, actually exists in a population of multiverses.
This is a great idea. It's compelling. But it hasn't been proven true, in part because we don't know how to prove it. It has some interesting implications, though, that there are other universes that we just don't see, and will never be able to see, because space is so warped that we wouldn't be able to see outside of the universe we're in now.
Do any of these topics make you uncomfortable?
No. Perhaps they are just indicators that our knowledge is incomplete.
You’ve won several awards for teaching. Do you have a secret recipe for that?
It’s important to respect the students. I enjoy teaching at all levels, but particularly students who are not science majors, because I think it's important to reach them as well. Some of those students may not be as mathematically sophisticated as a typical physics major, but they have other talents. I try to respect that and to reach them at their level.
What do you hope to achieve with your outreach work, and who do you hope to impact?
If scientists want to reach wider audiences — and we should — we need to engage with the public using formats beyond what an academic might prefer. You can reach people through TV or social media who may not otherwise be motivated to attend a public lecture or read a book. In my efforts, I hope I’m helping people develop an appreciation of science and to learn more about the scientific process.
Plus, because our scientific knowledge and understanding is growing every day, there’s a widening gulf between what scientists know and the knowledge base of the general public. It’s a very unsustainable situation — and potentially even a dangerous one, thinking of climate change or vaccines — to have a scientifically illiterate population. It’s incumbent on all scientists to engage with members of the public, to help continue to fight scientific illiteracy.
Liz Boatman is a staff writer for APS News.
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