On September 1, 2026, scientists working on the dark matter detector LUX-ZEPLIN (LZ) announced that they had registered an event, or particle interaction, for which they currently have no explanation.
The team from South Dakota in the US said that the signal resembles what, according to existing theories, could be produced by a dark matter particle when it collides with liquid xenon, the material used in dark matter detectors. writes DW.
However, the researchers did not go so far as to claim to have discovered or proved the existence of dark matter.
Term "dark matter" introduced by physicist Fritz Zwicky back in 1933 to explain why galaxies move faster than they should according to the amount of visible matter.
The news about the LUX-ZEPLIN experiment appeared only a few days after the release of the second season of the "Dark Matter" series, so the term "dark matter" once again came into the spotlight.
What exactly is dark matter?
Dark matter is often described as "invisible matter". However, it would be more accurate to say that it is "transparent". Namely, it does not emit light and does not reflect it, which is why it has never been directly observed.
However, its presence can be detected through the gravitational effect it exerts on stars, galaxies and other objects in space. That's why dark matter is thought to exist, even though we can't see it.
Is 95 percent of the universe invisible?
In broad terms, yes.
Ordinary matter, everything that people, planets, stars and galaxies are made of, makes up only about five percent of the universe.
Dark matter makes up approximately 27 percent. The remaining 68 percent is dark energy, a separate phenomenon associated with the accelerated expansion of the universe.
Together, dark matter and dark energy make up about 95 percent of the total content of the universe.
The figure of 85 percent is sometimes mentioned. It refers only to the share of dark matter in the total amount of matter.
Is there evidence that dark matter really exists?
One of the strongest arguments comes from the study of the so-called Bullet Cluster. It is about the collision of two large clusters of galaxies.
On that occasion, huge clouds of hot gas were created that reacted with each other, but the distribution of the total mass did not follow the distribution of that gas. In other words, part of the mass was located where there was not enough visible matter to explain it.
Many researchers believe that this "missing mass" is proof of the existence of dark matter.
How is dark matter searched for on Earth?
Scientists use very sensitive detectors like LUX-ZEPLIN. Such devices are generally located deep underground, where a thick layer of rock protects them from cosmic radiation that could disturb the measurements.
The detectors are made of materials with extremely low levels of natural radioactivity to reduce the possibility of false signals.
LUX-ZEPLIN works by tracking very faint flashes of light and electrical pulses that occur when a particle hits an atom of liquid xenon.
Xenon is a noble gas that has extremely good properties for registering radiation.
What is dark matter made of?
It is not known yet, but the main candidates are:
- WIMP particles (weakly interacting massive particles), which have been the leading theory for decades. They are thought to be very heavy and interact extremely rarely with ordinary matter.
- Axions, hypothetical particles of lower mass that could behave differently from WIMPs. Scientists from Kyoto University believe that traces of the action could be searched even through the Earth's magnetic field.
Does dark matter affect humans?
Most likely, it passes through our body constantly. It is assumed that billions of potential dark matter particles pass through each human every second.
However, interactions with the atoms of the human body would be extremely rare. It is estimated that only ten such particles could hit the atomic nucleus in the human body during the whole year.
Even then, the radiation exposure would be negligible and much less than what we are exposed to daily due to radon or cosmic radiation.
That's why dark matter, as far as we know today, has no measurable impact on human health.
Scientists continue to search for it for one simple reason: without it, much of what we see in space cannot be fully explained. If definitively discovered, it could change our understanding of the cosmos almost as much as relativity or quantum mechanics have.
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