Antimatter atoms get annihilated whenever they contact matter — which makes up everything. That makes them hard to study, which has been a problem, scientists say, because studying antimatter is key to understanding how the universe formed.
So the question has been, how can you manipulate antimatter atoms in order to study and measure them properly?
A team of scientists say they have figured out a way to do that by slowing down antimatter atoms with blasts from a special Canadian-built laser. And they say that could make it possible to create antimatter molecules — larger particles more similar to the matter we encounter in the real world — in the lab.
“This is where it really gets exciting for us,” said Makoto Fujiwara, a research scientist at TRIUMF, Canada’s particle accelerator centre in Vancouver, B.C. “You can really start doing things that are basically unimaginable previously,”
Fujiwara is a member of the international scientific collaboration known as ALPHA, which has created the Canadian-built laser they say could allow scientists to manipulate, study and measure antimatter like never before. The new technique would allow them to study its properties and behaviour in more detail, compare it to matter, and help answer some of the most fundamental questions in physics about the origin of the universe.
The collaboration, based at the underground lab of CERN, the European Organization for Nuclear Research, published the new research in the journal Nature Wednesday.
The group includes scientists from countries around the world, including Canadian researchers at the TRIUMF, University of British Columbia (UBC), Simon Fraser University, University of Victoria, British Columbia Institute of Technology, University of Calgary and York University in Toronto It receives funding from government agencies including the European Research Council and the National Research Council of Canada, and a few trusts and foundations.
What is antimatter?
According to our understanding of physics, for each particle of matter that exists, there is a corresponding particle of antimatter with the same mass, but opposite charge. For example, the “antiparticle” of an electron — an antielectron, usually called a positron — has a positive charge.
Antimatter is produced in equal quantities with matter when energy is converted into mass. This happens in particle colliders such as a the Large Hadron Collider at CERN. It’s also believed to have happened during the Big Bang at the beginning of the universe.
But there is no longer a significant amount of antimatter in the universe — a big puzzle for scientists.
Scientists would like to be able to study antimatter to figure out how it’s different from matter, as that might provide clues about why the universe’s antimatter has apparently disappeared. But there’s a problem — when antimatter and matter encounter each other, they both get annihilated, producing pure energy. (A huge amount — that’s what powers the fictional warp drive in Star Trek).
Because our world is made of matter, working with antimatter is tricky. For a long time, scientists could produce antimatter atoms in the lab, but they’d last just millionths of a second before hitting the matter walls of their container and getting destroyed.
WATCH | Bob McDonald explains why those earlier antimatter experiments were a big deal
Bob McDonald explains why the antihydrogen experiment is a big deal 1:59
Then in 2010, the ALPHA collaboration developed a way to capture and hold antimatter atoms using an extremely powerful magnetic field generated by a superconducting magnet. That magnetic field could keep them away from the sides of their container, which is made of matter, for up to half an hour — giving scientists plenty of time to do measurements on anti-hydrogen that compare it to hydrogen.
Makoto Fujiwara’s ‘crazy dream’
There was a problem though. Much as images you take with your camera are blurry if the object you’re photographing is moving too fast, it was hard to get precise measurements on hydrogen anti-atoms without being able to slow them down. But Fujiwara had an idea of how to do that.
“It’s one of my crazy dreams I had a long time ago — that is, to manipulate and control the motion of antimatter atoms by laser light,” he recalled.
He knew that regular atoms could be slowed down by “laser cooling” (atoms move more slowly at colder temperatures and stop moving at a temperature of 0 Kelvin or 0 K, equivalent to -273.15 C, called absolute zero). Atoms of each element are sensitive to specific colours of light. Hitting them with those specific colours under certain conditions can cause them to absorb light and slow down in the process.
WATCH | An ALPHA Canada animation explains how the ALPHA experiment makes and traps hydrogen and takes one kind of measurement
ALPHA Canada animation explains its breakthrough experiment 3:25
So as soon as ALPHA succeeded in trapping antimatter atoms of hydrogen, Fujiwara proposed trying laser cooling on them.
His colleagues laughed, initially, he recalled, “because everybody knew that a laser would be so hard to build for this.”
The colour they needed, represented in physics by its wavelength (for example, red has a wavelength of around 700 nanometres and blue has a wavelength of around 450 nanometres) had to be very precise. It needed a wavelength of exactly 121.6 nanometres . A laser of that colour had never been built before. The laser would also have to fit in a very confined space in a very complex experimental setup with lots of components.
Then, one day, Fujiwara ran into his colleague Takamasa Momose, a UBC chemistry professor, in the cafeteria at TRIUMF in Vancouver. He mentioned the problem, and Momose said he could make the laser.
The two worked together, and after nearly 10 years, they succeeded.
What you can do with ultra-slow antimatter atoms
Antihydrogen atoms are created and trapped at very cold temperatures, about 0.5 Kelvin or K (-272.65 C). But even at that temperature, they’re moving at about 300 kilometres per hour. With laser cooling, the researcher managed to get them down to 0.01 K (-273.14) and a speed of 36 kilometres per hour.
Makoto Fujiwara stands in front of ALPHA experiment apparatus at the European Organization for Nuclear Research (CERN) in Switzerland. The international collaboration equipped the apparatus with the special laser to slow down and cool antimatter atoms of hydrogen. (Maximilien Brice )
The team was able to measure the colours that represent the “fingerprint” of the cooled antihydrogen atoms. And those slow speeds, the measurement was four times sharper than the blurry measurements they had taken at faster speeds and higher temperatures.
Momose said that when the atoms move more slowly, it also allows them to bunch closer together — and perhaps even connect to form bigger particles of antimatter, which he said is his next goal.
“So far we have only antihydrogen atoms,” he said. “But I think it’s cool to make a molecule with antimatter.”
Fujiwara also wants to measure the force of gravity on the antimatter atoms to see if it’s the same as the force of gravity on matter. The force of gravity is very weak on something with as tiny a mass as an atom, and its signal typically gets drowned out by signals from other atomic movements. But because atoms stop moving at absolute zero, those other motions can be greatly reduced with extreme cooling.
Why it’s a ‘nice step forward’
Randolph Pohl is a professor of experimental atomic physics at the University of Mainz in Germany who was not involved in the study, but has worked with antimatter in the past. He has been following ALPHA’s work, and said its latest results are “a nice step forward” toward precise measurements of antihydrogen’s “fingerprint.”
But he thinks the new technique will have an even bigger impact on measurements of gravitational acceleration on antimatter atoms: “The big question is: will antimatter fall down to earth — will it be attracted to matter? Or could it be repelled by matter or fall upwards?”
He added that so far, no one expects a difference between matter and antimatter in its behaviour, but that theory still needs to be tested.
“Because there have been some occasions in the past where people measured something where nobody expected to see a discrepancy, and then suddenly a discrepancy showed up,” he said. “And that changed our view of the world.”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
