Physicists have been making incredible breakthroughs in physics for a while now. At CERN, they smash particles together at incredibly high speeds and, for a few fleeting instants, can generate particle-antiparticle pairs. These don’t last long, and once they’re gone, they’re gone. In all of its history, CERN has produced less than 10 nanograms of antimatter.
Now, scientists are tackling a different but related problem — dark matter and what it is. For years now, we have known something has to account for the expansion of the universe. The rapid, ever-increasing rate of growth just didn’t fit the calculations necessary for space-time to exist. Mathematically, it didn’t work. In reality, it was happening. This led to a lot of confusion and, eventually, the idea of dark matter became the leading theory.
Scientists estimate dark matter makes up about 85% of the matter in the universe. Despite its apparent majority, it’s never actually been observed. That means that even though it works mathematically and accounts for some of the abnormalities discovered in the universe, it’s still hypothetical. Dark matter was first theorized in the 1930s. The finding of real evidence took until the mid-2000s.
The Bullet Cluster, which was viewed using gravitational lensing, provided the first real glimpse of dark matter. The Bullet Cluster is two galaxies merging, which is one of the most explosive events in the universe. The matter its self would collide or mix as gravity expects, but dark matter doesn’t seem to interact with matter as we know it. This means any dark matter in the galaxy cluster would pass over and through the merge, with minimal change.
Scientists found almost exactly that. The evidence would never have been discovered without the concept of gravitational lensing. This is a technique for measuring the matter by the way the light bends. You see the same effect used to measure black holes, where light can go in but can’t get back out. This technique has now given credence to not one but two breakthroughs in cosmology.
But one positive finding doesn’t turn a hypothesis into a theory. Scientists still don’t understand what dark matter is, even though they’re pretty sure it exists. The next step, then, is to try and figure that out. There are a few particles that might fit the bill.
One of the most interesting ones is the axion. This is a hypothetical particle that interacts so lightly with matter that it would be almost impossible to detect. It would work well as an option for dark matter because of how light it is. However, we have yet to prove it exists. We can create antimatter here in laboratories, but we haven’t figured out how to create an axion.
That doesn’t mean people aren’t trying to find one, though. Researchers are using the Alpha Magnetic Spectrometer (ASM), a particle accelerator inside a giant magnetic tube attached to the International Space Station (ISS) to study antimatter and matter in space.
They hope to gain clues to what dark matter is made of, and they may have managed to get a start on that. The team, led by Nobel Prize laureate Samuel Ting, recently published a paper detailing their discoveries of new properties of boron, beryllium and lithium secondary cosmic rays. These new findings add to their discoveries about helium, carbon and oxygen rays.
The purpose of the giant magnet that is the ASM is to force the particles to bend. The rate at which they change their path allows the delicate instruments to measure their weight, which can give scientists a shocking amount of information about them. The ASM has also been responsible for finding new evidence for a larger amount of antimatter in the universe than was previously thought to exist. This could represent another dramatic change in how we view the universe around us.
However, the measurements that the ASM has picked up so far need to be replicated, and any confounding factors should be identified and mitigated. There were issues with the magnetic tube reacting with Earth’s magnetic field and causing the ISS to lose control. There are also potential mismeasurements with the accelerator its self, which could be why it has measured some antimatter particles, such as antihelium-3, something many researchers consider highly unlikely.
By measuring all the antimatter and the matter that the ASM can collect, Ting and his team hope to learn more about what dark matter could be. They’re still a long way from figuring that out, but as long as they have data to collect, they have the chance to make a breakthrough.