For years, astronomers have searched for the origins of ultra-high-energy cosmic rays, the most powerful particles in the universe. These energetic travelers move at nearly the speed of light, packing more punch than anything created in human-made particle accelerators like the Large Hadron Collider (LHC). Traditionally, scientists have suspected that such particles must come from violent cosmic events—exploding stars, colliding neutron stars, or even supermassive black holes devouring matter.

But a new research paper proposes an entirely different explanation—one that challenges long-held beliefs. The study, authored by a Russian astrophysicist and published in a preprint on arXiv, suggests that these extreme cosmic rays may not come from deep space at all. Instead, they might be produced right here in our Milky Way, created by dark matter particles known as scalarons annihilating each other in the vast reaches of our galaxy.

If this theory holds true, it could radically transform our understanding of dark matter, high-energy astrophysics, and the fundamental forces shaping the universe.

What Are Cosmic Rays, and Why Are They So Mysterious?

Cosmic rays are high-energy charged particles, mostly protons or heavier atomic nuclei, that constantly bombard Earth from space. Scientists first detected them in the early 20th century, and while most of them originate from well-known astrophysical sources—like supernova remnants, pulsars, or active galaxies—some are so incredibly powerful that their origins remain unexplained.

The most mysterious of these are ultra-high-energy cosmic rays (UHECRs), which exceed 10¹⁸ electron volts (eV) in energy. These particles:

• Travel at nearly the speed of light
• Contain trillions of times more energy than particles accelerated by human technology
• Should, in theory, lose energy over vast cosmic distances—but they don’t

The big mystery? If these particles were coming from billions of light-years away, they would gradually slow down due to interactions with cosmic microwave background radiation and galactic magnetic fields. Instead, they reach Earth at full strength, leading scientists to suspect that their true source must be much closer than previously thought.

A Radical New Theory: Cosmic Rays from Self-Destructing Dark Matter

The new study introduces a bold hypothesis: the highest-energy cosmic rays are not from exploding stars or colliding black holes, but rather from a process happening inside our own galaxy—the annihilation of a rare form of dark matter called scalarons.

What Are Scalarons?

Scalarons are theoretical ultra-heavy dark matter particles that may have formed in the earliest moments of the universe, during a period called cosmic inflation. Unlike normal matter, scalarons:

• Do not emit or absorb light, making them nearly impossible to detect directly
• Exist everywhere in the universe, potentially accounting for the missing mass scientists have long associated with dark matter
• Occasionally collide and annihilate each other, producing massive bursts of energy—including cosmic rays of unimaginable strength

According to the study, these scalaron interactions could explain why ultra-high-energy cosmic rays appear to originate from random locations in the sky, rather than from specific distant astrophysical sources.

Could This Be the Breakthrough That Unlocks Dark Matter’s Secrets?

Dark matter remains one of the biggest unsolved mysteries in physics. Though it makes up about 85% of the universe’s mass, we cannot see it or directly detect it. Scientists only know it exists because of its gravitational effects on galaxies and cosmic structures.

If the scalaron hypothesis is correct, it could provide the first direct evidence of dark matter particles interacting in a way that creates observable energy bursts. This could revolutionize our understanding of both cosmic rays and dark matter, offering a new way to study the invisible matter that shapes our universe.

However, there are competing theories. Some scientists believe ultra-high-energy cosmic rays could be produced by massive star-forming clouds or extreme magnetic fields inside our galaxy—explanations that do not require modifications to Einstein’s theory of general relativity, as the scalaron model does.