UWM team involved in physics work that wins Nobel
Last year’s historic discovery of gravitational waves emanating from the massive collision of two black holes more than a billion years ago — work that involved 1,000 scientists around the world, including a team at the University of Wisconsin-Milwaukee — was recognized with the 2017 Nobel Prize in Physics.
The discovery confirmed a century-old prediction made by Albert Einstein, the last major provision of his theory of general relativity that had remained unverified.
At 2:45 a.m. Tuesday, far from his UWM home, physicist Patrick Brady, 52, watched a video feed of the announcement in Stockholm with his wife, Rachel McGraw, and the two let out a cheer, popped a champagne cork and drank a toast. He’d come a long way from the 10year-old boy in Dublin, Ireland, who delighted in performing experiments with an electricity kit.
The citation from the Royal Swedish Academy of Sciences did not name any scientists from UWM but singled out their colleagues, Rainer Weiss, a professor at the Massachusetts Institute of Technology, and Kip Thorne and Barry Barish, both of the California Institute of Technology. Brady worked with the two Cal Tech scientists in the mid-1990s, shortly before UWM joined the hunt for gravitational waves around 1997.
Some 50 UWM scientists would come to be deeply involved in the project, which climaxed in February 2016 when the first announcement of the discovery was greeted with loud applause by scientists across the globe.
“For me, it is really an achievement I will forever be proud to have been a part of,” said Brady, director of UWM’s Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics.
The UWM scientists’ primary contribution was in establishing the complex system that calibrated all the data from two enormous L-shaped detectors in Hanford, Wash., and Livingston, La.
The detectors, with their 4-kilometer-long arms, are so powerful they were able to measure a tiny shift — less than 1/10,000th of the diameter of a proton — caused by the gravitational wave.
The wave traveled far in space and time, starting 1.3 billion years ago and finally passing through the Earth and every person on it on Sept. 14, 2015, somewhere around 4:51 a.m. Central time.
Gravitational waves are considered a fundamental part of the universe; they are generated by stars and even by our own bodies. Although the first wave detected came from one of the universe’s most violent events, the collision of black holes, there is a much simpler, less destructive way to create one.
Squeeze your hand into a fist and shake it.
“When you do that,” Brady explained, “you generate gravitational waves, extremely tiny ones. The gravitational wave travels away from your fist at the speed of light into the universe.”
It is not yet clear what practical technologies will flow from the discovery of gravitational waves. However, the Global Positioning System in cellphones used by millions around the world to get from place to place owes its accuracy to Einstein’s conception of a universe in which gravity curves space and time.
“When electricity was first discovered it was viewed as a toy,” Brady said. “They had no idea what it would enable. So it is possible in the future there will be technologies based around gravitational waves, but right now I can’t imagine what they will be.”
Super-massive black holes
Already, the equipment used to make the discovery has helped push optical technology to new levels.
UWM Associate Professor Xavier Siemens said the school already has physicists searching for gravitational waves at a frequency that is orders of magnitude smaller than those detected so far. The smaller frequencies should give science a glimpse of what are known as super-massive black holes.
Found at the center of galaxies, super-massive black holes are approximately a billion times the mass of the sun.
“I’d like to think that these kinds of discoveries lead to new ways of thinking. They will inspire a sense of awe and wonder in the universe,” said Siemens, 43, who still remembers the thrill of receiving a telescope from his mother when he was 7 and living in Spain.
The billion-dollar international project that sought the waves, known as the Laser Interferometer Gravitational-Wave Observatory, or LIGO for short, began around 1989.
Today, scientists believe that the discovery of the waves and other discoveries yet to be made will change how we see our universe.
“We can’t travel out to the distant universe. Everything we know about the distant universe is from stuff coming to us,” explained UWM physics professor Jolien Creighton, who has worked on the LIGO project for more than 20 years, almost half his life.
Until recently, what we could detect from these far reaches were two things: light and high-energy particles, such as neutrinos, Creighton said.
“Gravitational waves are the third major channel.”
UWM associate professor Alan Wiseman was the fourth key member of the school’s LIGO team.