Japanese researchers from Tokyo Metropolitan University have made a significant advancement in the study of dark matter. In an experiment lasting just a few hours, they established new limits on the lifetime of this mysterious substance’s particles, suggesting that dark matter’s lifespan could be millions of times longer than the age of the Universe.

The findings have been published in Physical Review Letters (PRL).

What Is Dark Matter and Why Is It So Hard to Detect?

Dark matter is a hypothetical form of matter that neither emits nor absorbs light, rendering it invisible to modern telescopes. Yet, scientists are confident of its existence due to gravitational anomalies, such as the unexpectedly high rotation speeds of galaxies.

Despite decades of searching, the precise nature of dark matter remains one of the Universe’s greatest unsolved mysteries.

A New Approach to Hunting Axion-Like Particles

The researchers focused on axion-like particles (ALPs), a leading candidate for dark matter. These particles are theorized to decay while emitting infrared light. However, studying the infrared spectrum is challenging due to numerous interferences, including:

  • Zodiacal light (the glow from dust particles in the Solar System)
  • Atmospheric radiation
  • Other noise effects

To overcome these obstacles, the team employed the WINERED spectrograph on the Magellan Clay Telescope, which enables highly precise analysis of narrow infrared wavelength ranges.

Key Finding: Dark Matter Outlives the Universe by Far

After analyzing the data, no signs of ALP decay were detected. This absence, however, yielded a groundbreaking insight:

  • The lower limit of dark matter particles’ lifetime is now estimated at 10²⁵ to 10²⁶ seconds.
  • This is tens of millions of times greater than the Universe’s age, approximately 4.3 × 10¹⁷ seconds (about 13.8 billion years).
  • These constraints are the strictest established to date.

What’s Next?

While direct detection of dark matter remains elusive, the researchers noted anomalies in the data that might hint at its presence. Further observations and analyses will be necessary to confirm these findings.

This study demonstrates that cutting-edge infrared spectroscopy technologies can bring humanity closer to unraveling one of physics’ most profound mysteries.