Cosmic rays can be detected using cloud chambers—containers where alcohol vapor condenses around trails of ions created by these high-speed particles from space.

Learn how to build your own cloud chamber to detect cosmic rays—particles from space that move near the speed of light—at home.

Scientists have determined the properties of cosmic rays by analyzing their trajectories in bubble chambers—containers filled with a vapor that clings to charged particles.

Antimatter was discovered by examining debris from collisions between atmospheric gases and cosmic rays—high-energy matter particles from space.

Particle detection has evolved from cloud and bubble chambers to digital 3D displays

As invisible particles passed through cloud and bubble chambers, they disrupted supersaturated vapor and superheated liquid, respectively, creating trails that served as proxies for cosmic rays. The transition from photographed events to digital sensors enhanced data collection and accuracy.

Cosmic rays are evidence of incredibly powerful astronomical events—solar cosmic rays provide information about eruptions and flares on the sun's surface, while galactic cosmic rays shed light on dying stars.

Research shows that cosmic rays may trigger the cascade of displaced electrons needed to produce lightning, which is also enabled by pointed ice crystals that create strong electric fields.

Cosmic rays are thought to be accelerated to near the speed of light by repeatedly bouncing across shockwaves produced by high-energy cosmic events, such as supernovae.

Some cosmic rays possess energies as high as 100,000,000 teraelectron volts—more than 10 million times the energy of particles accelerated in the Large Hadron Collider.

By measuring them in hot-air balloons during a partial solar eclipse and at night, Victor Hess discovered cosmic rays and concluded they came from beyond the solar system.

Particles produced in cosmic ray showers that would normally decay long before they reach Earth's surface are observed in ground-based detectors because they experience time more slowly when moving near the speed of light—a phenomenon predicted by special relativity.

If particle accelerators did create black holes by packing tremendous energy into a small volume, then trillions would be created in Earth's atmosphere daily by cosmic rays.

Particle accelerators detect subatomic particles using millions of sensors

Calorimeters measure the energy of particles. Tracking devices can measure momentum and charge from the trajectory of particles, which is determined by recording tiny electrical signals. Time-of-flight detectors provide particle velocities directly and particle mass indirectly, giving physicists a suite of properties to compare with those of known matter.

In 1997, the Compton Gamma Ray Observatory identified 'positron geysers'—fountains of antimatter particles—emerging from near the center of the Milky Way.

Tom Liggett, a Bournemouth University student, sent sealed photographic film into space using a helium balloon, producing photographs from cosmic rays.

In 2017, a hidden chamber was found in the Great Pyramid of Giza by measuring particles created in the collisions between cosmic rays and atmospheric particles.

Cloud 9 is a dark-matter-dominated failed galaxy

Identified in 2023, the starless, gas-rich object is the first of its kind seen by astronomers and provides a window into the early stages of galactic formation without observations relying on visible matter as a proxy. The existence of such REHLICs, or Reionization-Limited-H I Clouds, was predicted by cold dark matter cosmological models.

At CERN's Antimatter Factory, researchers create and guide antiprotons and antielectrons together to form antihydrogen, and all these antiparticles are analyzed to help scientists study the behavior of antimatter.

Before 1932, when particle accelerators were first used for nuclear research, scientists relied on naturally radioactive substances to advance their understanding of the atomic nucleus.

Antimatter can be created from dark lightning—high-energy light emitted by deflected electrons after they are accelerated to near the speed of light by thunderstorms.

Earth's magnetic field, which deflects charged particles, helps protect us from cosmic rays, but the sensitivity of these particles to magnetic fields also makes it difficult for astronomers to determine their sources.

Particle accelerators propel matter toward small targets at high speed

Devices like cathode-ray tube televisions were once basic particle accelerators, but modern ones, such as the Large Hadron Collider, use massive magnetic fields and circular tunnels to achieve energies high enough to recreate the conditions just after the big bang.

Cloud formation requires water vapor and condensation nuclei to build from

The nuclei—particles like dust, salt, and smoke—act like jumpstarts that water molecules can start to accumulate onto to form clouds. Condensation nuclei are about 1/100th the size of cloud droplets, which are mostly water.

As seen in the dark region of the Horsehead Nebula, clouds of space dust can block some forms of light from reaching telescopes, impairing observations and data collection.

Within ALICE—A Large Ion Collider Experiment—at the Large Hadron Collider, scientists have created quark-gluon plasma—an exotic form of matter present in the moments after the Big Bang.

Delays in the decay of unstable particles provide evidence for time dilation

Physicists used the muon half-life measured in labs to predict how many should reach detectors on Earth's surface after their production in collisions between atmospheric molecules and cosmic rays. Higher detection rates were consistent with a longer half-life due to slower movement through time.

Cosmogenic nuclide dating reveals how long a surface has been exposed to air by measuring the abundance of rare isotopes produced when cosmic rays interact with minerals.

Scientists are experimenting with ways to probe the multiverse theory

Researchers are simulating vacuum bubbles—the theorized starting points of universes—using quantum computers, digital models, and exotic lab setups to study how they form, expand, and possibly collide. One experiment aims to "blow" artificial universe-like bubbles inside ultra-cold quantum gases, potentially capturing real-time glimpses of cosmic birth processes in a lab.

The cosmic microwave background radiation is the oldest light in the universe

Just after the Big Bang, the high-density universe prevented light from traveling very far before being absorbed and emitted repeatedly by free-floating particles. As the universe expanded, electrons and protons combined to form hydrogen, thereby freeing up space for light to travel unimpeded, creating the background light we observe today.

The Curies developed a way to measure radioactivity in an old medical dissecting room

Despite lacking proper laboratory conditions, Marie and Pierre built an ionization chamber and a piezoelectric quartz electrometer to measure the amount of charged particles released by radiation, with a sensitivity of ten-trillionth of an ampere. Substances with different emission rates indicated different elements.

At the CERN Control Center, where the Large Hadron Collider and connected accelerators are managed, champagne bottles from parties commemorating major milestones, such as the first collisions or a new record energy, are collected.

About 10% of the radiation people are exposed to each year comes from outer space, with higher percentages for those living at higher elevations or who fly often.

The scattering of light in the early universe prevents seeing the beginning of time

A "cosmic fog" of elementary particles in the early universe prevented light from traveling far before being absorbed. Only 380,000 years after the big bang, when the first atoms formed, was light free to travel and reach telescopes for study.

Scientists have tested atmospheric models by firing rockets into the aurora borealis

Functioning like components of a CT scan, the missiles transmit signals that can be used to identify charged particles and electromagnetic currents in slices. The slices are then combined to construct a computer-based model of Earth's atmospheric structure, which is used to compare the accuracy of physics-based models.

Watch how the machine at the heart of NASA's Cold Atom Lab produces atoms near absolute zero—the coldest theoretical temperature in the universe—for experiments involving quantum phenomena.

Cathode rays are beams of electrons that emit light when hitting a fluorescent screen

When these beams are emitted into an evacuated tube containing charged plates or a nearby magnet, deflections are observed due to the electron charge. In 1897, J.J. Thomson's calculations of this deflection led to his discovery of the subatomic particle.

Each year, the Large Hadron Collider undergoes a winter shutdown—when electricity costs are highest—and bringing it back online requires weeks of tests, including some involving high-energy particles from outer space.

At the Large Hadron Collider, scientists have transformed lead into gold—a process known as chrysopoeia, which alchemists sought for centuries.

The conditions needed for cloud iridescence, or rainbow clouds

The relatively rare phenomenon occurs when sunlight scatters off tiny water droplets or ice crystals in thin, newly-forming or semi-transparent clouds, such as altocumulus, cirrocumulus, lenticular, and cirrus varieties. This effect is similar to what is seen in soap bubbles and mother-of-pearl shells and produces pastel-like colors.