By the end of March, an international team of physicists aims to awaken a monster machine from its two-year slumber and use it to hunt down one of the most elusive and mysterious particles in the universe: a dark matter particle.
The machine, called the Large Hadron Collider, is nestled underground in the suburbs of Geneva, and is the largest, most powerful particle physics accelerator in the world.
Inside the machine’s long, underground, oval-shaped tunnel, physicists make subatomic particles like protons and neutrons move at nearly the speed of light.
Typically, they point two beams of particles at each another, so that they smash into each other in cataclysmic, head-on collisions. These collisions generate hot clouds of debris that reach temperatures 100,000 times hotter than the center of the sun and can include new, never-before-seen particles.
Such was the case during the LHC’s first run from 2009 through 2012, and now, after two years of heavy maintenance, the European Organisation for Nuclear Research (CERN) is getting ready for round two. They plan to turn the LHC on sometime at the end of March (they haven’t announced a set date) and then slowly ease up to maximum power over the next two months, according to a recent announcement from a panel of physicists during a press conference held Thursday, March 12.
Expectations are high for the LHC’s Run II. Afterall, the accelerator already has one Nobel Prize to its name. That prize was awarded in 2013 when the LHC detected a Higgs boson for the first time in history — after 50 years of searching. (You might know this particle by another name, the “God” particle, but never call it that in the presence of a physicist if you want their respect.)
The biggest scientific discovery of the 21st Century
The detection of a Higgs boson is considered by some to be the biggest scientific discovery of the 21st Century, and for good reason. Higgs bosons come with what physicists call a Higgs field, which is responsible for giving all of the atoms in the universe, like the atoms that make up people, their mass.
If the LHC team had not found a Higgs boson, it would have left a gaping hole in physics theory. Because without this vital particle, physicists can’t explain how the universe developed objects like galaxies, stars, planets, and, ultimately, life.
With round two just around the corner, the LHC team’s goals are as lofty as ever.
“Now that they have produced a Higgs boson, number one on their list is dark matter,” Michael S. Turner, Director of the Kavli Institute for Cosmological Physics, said during a Google Hangout on March 9.
The first light in the dark universe
Figuring out what dark matter is would be as much of an achievement as discovering a Higgs boson.
Right now, astrophysicists are at a real loss if you ask them what the universe is made of. A big chunk of it (26.8% to be exact), is composed of dark matter, which is inherently invisible and not well understood.
As far as astrophysicists can tell, dark matter is an exotic type of particle that doesn’t interact with anything we can see. Because of this quality, it’s nearly impossible to detect. The only reason scientists are convinced dark matter exists at all is because of the gravitational influence it has on other objects, like galaxies and stars.
If dark matter is a type of particle, the LHC should be able to make one in much the same way that they made a Higgs boson — by smashing beams of particles together. And with its new upgrades, which include twice the power and five times the number of collisions, the LHC could just pull it off.
“We gain much more because of higher energy and higher mass particles, really a lot more capability to see new particles,” German particle physicist Rolf Heuer, who is the Director General of CERN, said during the press conference on March 12.
Whether they will actually find a dark matter particle or not before 2018, when the LHC will be shut down for another upgrade, remains to be seen. In the meantime, thought, they can dream.
“I have a dream: I want to see the first light in the dark universe,” Heuer said. “If I see that, then nature is kind to me.”
Dark matter is just one of the many goals physicists hope to meet with the LHC’s second run over the next three years. At the start of 2018, physicists will once again shut the LHC down for a couple years more of maintenance. This on-again, off-again pattern is scheduled to continue until 2035.
What will we find in the coming decades? Only time will tell.