Although scientists largely believe dark matter is real, no one has been able to see or create it. Data collection and performance improvements at the particle crusher, dubbed the Large Hadron Collider, could offer researchers one of their best chances to visualize and understand the substance.
“If we can figure out the properties of dark matter, we’ll learn what our galaxy is made of,” said Joshua Ruderman, associate professor of physics at New York University. “It would be transformative.”
Dark matter has fascinated physicists for decades. It’s widely believed to make up a significant part of the universe, and learning more about it could provide clues as to how the universe came into being.
All the stars, planets and galaxies in the universe make up only 5 percent of the matter in the universe, according to scientists at CERN. About 27 percent of the universe is thought to be made up of dark matter, which does not absorb, reflect, or emit light, making it extremely difficult to detect. Researchers say it exists because they’ve seen its attraction to objects — and seen how it helps bend light.
Researchers hope the Large Hadron Collider can help. The collider was built by the European Organization for Nuclear Research over a decade to help answer unanswered questions in particle physics. The machine is about 100 meters underground in a tunnel near the French-Swiss border and the city of Geneva. Its perimeter stretches nearly 17 miles.
Inside the collider, superconducting magnets are cooled to about 456 degrees Fahrenheit – colder than space – while two beams of particles traveling at nearly the speed of light are collided. Using advanced sensors and monitors, scientists are analyzing the substances created by these collisions, which replicate conditions similar to those of the Big Bang. It allows them to learn about it the earliest moments of the universe.
The machine was commissioned in September 2008, but has been shut down several times for improvements. Over the past three years, engineers have upgraded the collider so it can collect more data and run at faster speeds. Now the accelerator can operate at its highest energy level ever, 13.6 trillion electron volts, allowing scientists to conduct larger, more complicated experiments that could provide new insights into particle physics.
“That’s a significant increase,” said Mike Lamont, CERN’s director of accelerators and technology. “Paving the way for new discoveries.”
At the dawn of the universe, particles had no mass, so scientists have long wondered how stars, planets, and extra life came about. In 1964, physicists François Englert and Peter Higgs and others theorized that a force field gave mass to particles when they combined, but they could not document the entity’s existence.
The discovery of the Higgs boson, part of the hypothetical force field, earned Englert and Higgs a Nobel Prize in Physics.
The particle has intrigued scientists and the general public alike. CERN and the Collider are featured prominently in the Dan Brown book and adapted film Angels & Demons.
But now the researchers want to answer even more irritating questions, particularly those about dark matter.
During the four-year Large Hadron Collider experiment, scientists hope to find evidence of dark matter. When they start the machine, the protons spin at almost the speed of light. The hope, the researchers said, is that when they collide, new particles are created that resemble properties of dark matter.
They also hope to learn more about how the Higgs boson behaves. On Tuesday, shortly after the collider began collecting data, scientists at CERN announced they had found three new “exotic” particles that could provide clues as to how subatomic particles bind to one another.
“High-energy accelerators remain the most powerful microscopes available to us to study nature at the smallest scale and to discover the fundamental laws that govern the universe,” said Gian Giudice, head of the theory department at CERN.
New York University’s Ruderman said CERN’s quest to learn about dark matter and explain the origins of the universe has him eagerly awaiting the results of the experiment. Research is very appealing to him. “That’s why I wake up in the morning,” he said.
Once data comes out of the experiment, Ruderman will see if it produces new particles. Even if this is the case, it will be difficult to say immediately whether it is dark matter or not.
First, they have to assess whether the particle in question emits light. If it does, it’s less likely to be dark matter. Second, since dark matter should theoretically last for billions of years, the particle should show signs of longevity and not instantaneous decay. They also hope the particle behaves similarly to current dark matter theories.
Ruderman said it could take more than four years to make the discovery.
If CERN scientists don’t discover dark matter in the next four years, they have more upgrades in the works. The upgrades are expected to take three years after the end of the current run, allowing the fourth round of data collection and experiments to begin in 2029.
As planned, the study could collect 10 times more data than previous experiments, according to the CERN website. But unraveling the mysteries of the universe is not easy.
“This is difficult,” said Ruderman, “and something that could take a lifetime of exploration.”