Astronomers are probing millions of miles into space, grappling with the mechanics of the universe. As a veteran of this stellar quest, UCLA astrophysicist Rene Ong is seeking a mysterious particle that could unlock answers a little closer to home — at the South Pole.
Ong is hunting the WIMP, or Weakly Interacting Massive Particle. Its name is a bit misleading: It’s massive, relatively, up to a thousand times heavier than the everyday particles that make up everything from hair to helium. WIMPs surround us but because they do not react strongly with other subatomic particles that make up our bodies, they can pass through us like phantoms.
To make it even trickier, they are not only invisible, but also hypothetical.
Despite intense searches through powerful telescopes in Hawaii and Arizona as well as under the ground in South Dakota, WIMPs remain elusive. But the laws of physics — and tantalizing glimpses of signature traces in their passing — suggest they are not only around us but also either the ancestors of, or part of, the cosmic substance known as dark matter.
This is the “stuff” that makes up 85% of matter in the universe. It, too, is intangible, working with gravity but not light. If we could see dark matter, it would appear as glowing halos and galaxy-spanning tendrils, a gravitational glue that anchors stars together in a cosmic dance. Without it, stars would fly apart and make the chances of life as we know it even more remote.
A working hypothesis is that WIMPs came into existence alongside space and time at the birth of our universe 13.8 billion years ago, in a singular event called the Big Bang. As the universe cooled, energy congealed into various forms of matter, including dark matter. But until some of these early particles are pinned down and studied, we cannot answer the biggest and most enduring question in cosmology: Why does our universe exist at all?
Which is why Rene Ong, distinguished professor in the UCLA Department of Physics and Astronomy, has been monitoring a balloon circling the South Pole.
Penguins and Particles
Ong is part of a team of international scientists operating the General AntiParticle Spectrometer, or GAPS. The house-sized balloon was launched last December from Antarctica’s McMurdo Station — the largest of the many research stations on the continent — to track and trap low-energy particles in its clean atmosphere. Twenty miles high, it’s seeking exotic particles such as antideuterons, which are a telltale sign that two WIMPs have met, exploded on contact and annihilated each other, leaving a trace behind.
The experiments are being carried out in the penguin paradise of Antarctica because there is less electromagnetic interference for the low-energy particles floating about like colorless balls in the air.
Ong suspects WIMPs are very similar, if not identical, to dark matter. Proof of their existence, obtained by trapping a WIMP or its aftermath debris, could reveal secrets of the universe such as how dark matter works, as well as whether the particles could one day be turned into the kind of fuel that drives spaceships in a Star Trek–like future. But that would be for another brilliant generation of UCLA physicists to untangle.
If antideuterons are detected, says Ong, “there would be a host of scientific papers the next day.” But he also knows this could be years away.
Then there is the matter of antimatter, which resembles ordinary matter but is electrically charged in opposite ways — if the two particles meet, they “blow a fuse” and annihilate each other.
Both, goes the theory, were made at the same time, and yet there is far less antimatter — maybe one particle in a billion. That doesn’t make sense to Ong. Could the WIMP show us where the rest of it’s been hiding?
A still-mysterious world
It’s all deeply mysterious, says Ong — and worth investigating. “We have this really strange situation where almost all of the material that we see in the universe is matter, and there’s very little antimatter,” he says.
So, where is it? “This paradox, which we call baryon asymmetry, is one of the things that confounds us,” he says. “Why is our universe made of matter? Why do we even exist when all the conditions from the early universe imply that we shouldn't really be here? So there's something very strange going on. We don’t understand why we live in a matter-dominated universe.”
One hypothesis is that WIMPs are themselves dark matter, fragments left over from a hotter universe before it congealed. Or maybe they link many types of particles, as they demonstrate behaviors associated with matter, antimatter and dark matter. Or maybe they are dark matter. Questions, questions and more questions.
“It’s like looking for your keys under the lamppost — if you know you’ve lost your keys on your way back home at night, you’re not going to find them in some dark spot. You're first going to go over to the lamppost, where there's light,” Ong says. “Antimatter is one of the lampposts under which we’ve never looked deeply enough to see if we can figure out what dark matter is.”
No matter what we learn about antimatter, that Star Trek warp drive will probably always be the stuff of fantasy. But maybe that’s for another generation of brilliant UCLA scientists to boldly figure out.
Read more from UCLA Magazine’s Fall 2026 issue.
