Scientist at Work: Nikodem Poplawski
Give Nikodem Poplawski a bath towel and a couple different balls and he'll describe a way of looking at our universe with a story that doesn't include any "Big Bang" characters. For Poplawski, a postdoctoral researcher who earned his M.S. and Ph.D. in physics from Indiana University in 2004, the universe is all about the bounce, not the bang.
Nikodem Poplawski displays "tornado in a tube" for a Science Channel film crew that visited IU Bloomington recently to film an upcoming episode of "Morgan Freeman's Through the Wormhole." The top bottle symbolizes a black hole, the connected necks represent a wormhole and the lower bottle symbolizes the growing universe on the just-formed other side of the wormhole.
To explain, Poplawski uses a stretched towel to represent spacetime, then places a heavy ball on the towel to symbolize a massive star's matter generating the energy and momentum that curves spacetime. It's when he twists the towel around the ball to exhibit the intrinsic angular momentum of matter -- the spin of elementary particles -- and how matter (the ball, in this case) can twist spacetime and generate torsion, that his theory takes shape.
"The representation here is only symbolic as spacetime torsion is more difficult to visualize than curvature," Poplawski explains. "But the point is that torsion exists only at locations where matter exists, unlike curvature, which can propagate in a vacuum as gravitational waves. Torsion doesn't exist in a vacuum."
Torsion counters gravity in this adaptation of general relativity, but just as in general relativity, massive stars end up as black holes, from which nothing, not even light, can escape. It is here that gravity first overcomes the repulsive forces of torsion, matter collapses into the black hole and, finally, torsion re-exerts itself and prevents matter from compressing further. Now Poplawski's bounce comes into play.
"The matter instead reaches a state of finite, extremely large density, stops collapsing, rebounds like a spring, and starts rapidly expanding," he said. "Extremely strong gravitational forces near the bounce cause an intense particle production, increasing the mass inside a black hole. The rapid recoil after the bounce could be what has led to our expanding universe."
Poplawski's explanation of how torsion is responsible for the bounce and the formation of a new universe in a black hole appeared in his research "Cosmology with torsion: An alternative to cosmic inflation," last year in Physics Letters B.
Use of this adaptation of general relativity, called the Einstein-Cartan-Sciama-Kibble (ECSK) theory of gravity, also led Poplawski to publish another paper last year that conjectured that every black hole produces a new daughter universe inside itself, and then becomes a wormhole (also known as an Einstein-Rosen bridge) to this universe from a mother universe in which the black hole exists.
"Accordingly," he wrote, "our own universe could be the interior of a black hole existing in another universe. The passage of matter through the black hole's boundary, called the event horizon, can only happen in one direction, providing a time asymmetry in the new universe inside. The arrow of time in a daughter universe would thus be inherited, through torsion, from a mother universe."
The paper, "Radial motion into an Einstein-Rosen bridge," was published in Physics Letters B in April 2010 and discussion about the work has yet to cease. National Geographic News named the story one of its "Top Ten Discoveries of 2010," coming in at No. 6, and the American Association for the Advancement of Science, which publishes Science, not only listed it among its Top 10 favorite and most popular stories for 2010 at its ScienceNOW site, but went so far as to name it "our most popular story of all time." After nearly a year since publication, readers at both sites were still commenting on the story.
It was his work published in the "Cosmology with torsion: An alternative to cosmic inflation" and use of the ECSK gravity theory that drew the attention of the Science Channel and that warranted a story in New Scientist magazine.
"I think the questions about the origin of our universe, the origin of the Earth, Sun and Moon and the origin of life and all observed species have always been the questions that people wanted to answer," Poplawski said. "While the formation of the Sun and Earth is better understood, the origin of the universe as a whole remains unknown. That is why it is a subject of fascination."
And he says black holes are objects of similar fascination because they are the most extreme states of matter and spacetime. Described mathematically just like elementary particles by only three parameters -- mass, angular momentum, and electrical charge -- they are simple, yet mysterious.
"I also think that the origin of the universe can be associated with religion and that is why the general public is so fascinated," he added.
Poplawski recently spent an entire day with a film crew from the Science Channel to produce an episode on the young researcher's work. The program, "Through the Wormhole with Morgan Freeman," will air later this year.
Over the next two months Poplawski will present his latest theoretical work at the Center for Theoretical Astrophysics at the University of Illinois Urbana-Champaign and at the 218th meeting of the American Astronomical Society.
Already this year he's had related work published in the Berlin-based Annalen der Physik, the oldest physics journal in publication (since 1790) and where Einstein first published his E=mc2 formula in 1905. There Poplawski published "Cosmological constant from quarks and torsion," a paper that provides a basis for a torsion-induced dark energy. "Matter-antimatter asymmetry and dark matter from torsion," an explanation of the observed imbalance between matter and antimatter and the origin of dark matter, was published this month (April) in Physical Review D.
Born in Torun, Poland -- the birthplace of Copernicus -- Poplawski is the son of two trained artists, yet his interests as a youth leaned to chemistry and astronomy.
"In high school I found that chemistry and astronomy cannot answer more fundamental questions, so my interests moved to physics, which appeared to provide a more general view of the universe and the physical world," he said. "I decided that I wanted to find the origin of the universe and the nature of elementary particles and that is why I study theoretical physics. My goal became to unify the theory of gravity with quantum theory. I also find the universe beautiful, so I also began to study astrophysics and cosmology."
He'd planned to stay and study in Europe after earning an initial M.S., in astronomy, from the University of Warsaw, but found himself at IU after being convinced by a former high school friend who'd attended the university that it was a "leading university with friendly people and a nice campus."
