Test: What is dark matter and what experiments are trying to detect it

July 7, 2026 · 6 min read

Question: What is dark matter and what experiments are trying to detect it?

Perplexity

Dark matter is a hypothetical form of matter that does not participate in electromagnetic interactions (it does not emit, absorb, or reflect light), making it impossible to detect through direct observation[2][3]. Its existence is confirmed only by indirect evidence: it manifests solely through its gravitational influence on the motion of stars in galaxies, the distribution of mass in colliding galaxy clusters (e.g., in the famous "Bullet Cluster"), and the effect of gravitational lensing[1][2]. Dark matter constitutes about 22–27% of the total mass-energy of the universe and, according to current theories, is primarily composed of unknown massive weakly interacting particles (WIMPs), whose mass is tens of times greater than that of a proton[3][4].

To detect dark matter particles, complex experiments are conducted in underground laboratories, where the thickness of the Earth (for example, in former gold mines 1.6 km deep near the town of Lead in South Dakota) blocks all cosmic particles except for hypothetical dark matter particles[1][3]. In setups like a giant "cryostat" tank with liquid xenon, a dark matter particle can interact with a gas nucleus, ionizing it and decaying into visible photons, the flash of which is registered by a "time projection chamber" detector[1][3]. Colliders are also used – enormous devices that accelerate beams of charged particles to near-light speeds and collide them, in the hope that unknown particles associated with dark matter might be born from the collision[1]. Despite 20–30 years of searching for WIMPs and launching experiments costing $60 million, dark matter particles have not yet been detected, although the probability of their registration in future experimental stages is estimated at 10–50%[3][4].

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Gemini

Dark matter is a hypothetical form of matter that does not interact with electromagnetic radiation, making it invisible to direct observation. Its existence is confirmed by indirect evidence, primarily its gravitational influence on visible matter. According to current estimates, dark matter constitutes about 27% of the universe's mass-energy, while ordinary, baryonic matter makes up only about 5%. The missing mass observed in galaxies, for instance, in their rotation speeds, is attributed to the presence of dark matter.

The search for dark matter is being conducted in numerous ways. One of the main directions is the search for so-called "WIMPs" (Weakly Interacting Massive Particles). Experiments like XENON use large volumes of liquid xenon to detect the faintest flashes of light or ionization that might occur when a WIMP collides with a xenon nucleus. Other experiments, such as CDMS and CRESST, also aim for direct detection of such particles. Recently, a new experiment, QROCODILE, was introduced, which investigates the possibility of detecting "light" dark matter particles. Furthermore, scientists are exploring the possibility of detecting dark matter through gravitational waves from black hole mergers, as seen in the analysis of the GW190728 signal. It is important to note that despite active searches and some intriguing signals, such as in the DAMA/LIBRA experiment, conclusive experimental confirmation of the existence of dark matter particles has not yet been obtained.

Sources:

Dark Matter - Wikipedia
Dark Matter Detectors
Dark Matter. Myth or Reality? / Habr
Dark Matter - Elements of Big Science
No One Has Seen It, But Everyone Knows: What is Dark Matter and How is It Studied | New FizTech. ITMO University
New Dark Matter Search Experiment Yields First Data - Science
XENON (experiment) - Wikipedia
What is Dark Matter? : r/askscience - Reddit
Experiment Refutes Hypothesis of Dark Matter Detection - Science Mail
New Method for Detecting Dark Matter Yields First Result - Hi-Tech+

ChatGPT

Dark matter is a hypothetical form of matter that does not emit, absorb, or reflect light, making it invisible to all forms of electromagnetic radiation. It was introduced into cosmology to explain observed anomalies in the motion of galaxies and gravitational effects on a universal scale that cannot be accounted for by visible matter alone. According to current estimates, dark matter constitutes about 27% of the total mass-energy of the universe, with ordinary matter making up only about 5%. The primary evidence for the existence of dark matter includes galactic rotation curves, gravitational lensing observations, and cosmic microwave background mapping.

Several approaches are being developed in experimental physics to search for dark matter. One of these is direct detection experiments, which aim to record rare interactions of dark matter particles with matter in specially equipped underground facilities, shielded from cosmic radiation and noise. Examples of such experiments include Xenon1T, LUX-ZEPLIN, and PandaX, which use materials like xenon or argon. Another approach involves colliders, such as the Large Hadron Collider (LHC), where attempts are made to create dark matter particles in high-energy proton collisions. A third method involves cosmic observations of dark matter particle annihilation or decay in space, which can produce cosmic rays or gamma radiation detected by satellites, such as the Fermi telescope.

All these methods are complementary and allow for the testing of different hypotheses about the nature of dark matter, whether they are weakly interacting massive particles (WIMPs), axions, or other candidates. Despite decades of searching, dark matter remains a mystery, stimulating the development of new technologies and theories in particle physics and cosmology.

Sources:

NASA — Dark Matter
CERN — What is Dark Matter?
Xenon Collaboration results

Grok

Dark matter is a hypothetical form of matter that does not interact with electromagnetic radiation, meaning it does not emit, absorb, or reflect light, remaining invisible to ordinary telescopes. Its existence is inferred from gravitational effects: anomalously high galaxy rotation speeds, gravitational lensing, and the structure of the large-scale universe. According to current estimates, dark matter constitutes about 27% of the universe's energy and approximately 85% of all matter, while ordinary (baryonic) matter makes up only about 5%. The main candidates for dark matter particles are weakly interacting massive particles (WIMPs), axions, or, less commonly, primordial black holes.

The search for dark matter is being conducted in three directions. Direct detection takes place in underground laboratories, where highly sensitive detectors (often based on liquid xenon) attempt to register rare collisions with WIMPs. Key projects include LUX-ZEPLIN (LZ) in the USA, XENONnT in Italy, PandaX in China, and SuperCDMS in Canada; in 2025–2026, LZ and SuperCDMS have already provided new stringent limits on the interaction cross-section, but a signal has not yet been found. Indirect searches involve observing annihilation or decay products (Fermi-LAT, AMS-02 experiments), and at the Large Hadron Collider, traces of dark matter particle production in proton collisions are sought. New quantum detectors and technologies, such as TESSERACT, promise to increase sensitivity in the coming years.

Sources:

What Is Dark Matter? (NASA Space Place)
Dark matter (CERN)
Dark matter (Wikipedia)
DOE Explains...Dark Matter (U.S. Department of Energy)
LZ Dark Matter Experiment (lz.lbl.gov)
Dark matter experiment reaches ultracold milestone (Phys.org, 2026)
Progress and prospects in the underground laboratories' search for dark matter (Nature, 2026)

Claude

Dark Matter: Definition and Search in Underground Laboratories

Dark matter is an invisible substance that does not emit or absorb light. Its existence is evidenced by gravitational effects that astronomers observe when studying galaxies and star clusters. Ordinary matter accounts for about 4% of the total mass-energy in the universe, while the remaining 96% includes dark matter and dark energy. Dark matter makes up about a quarter of the universe's mass-energy and manifests itself only through gravitational interaction.

Scientists use several approaches to detect dark matter particles. The XENON1T experiment is the world's most sensitive dark matter detector, filled with 3.2 tons of ultra-pure liquid xenon, which generates faint light signals and free electrons when particles interact with xenon atoms. When a dark matter particle collides with an atomic nucleus or an electron, it can cause a microscopic flash of light or ionization, which are captured by highly sensitive sensors. To avoid false positives from background radiation, such experiments are located deep underground, away from cosmic rays. Recent developments include the SuperCDMS detector, located two kilometers deep in Canada's SNOLAB laboratory, which uses sensitive superconducting sensors and silicon and germanium crystals.

Sources:

MSU Nuclear Physics Portal (nuclphys.sinp.msu.ru)
Great Russian Encyclopedia (bigenc.ru)
Indicator Journal (indicator.ru)
HighTech+ (hightech.plus)
RBC Trends (trends.rbc.ru)

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