Dark matter, if it exists, has a strictly limited lifetime, new study says
Dark matter has puzzled scientists for decades, stirring endless debate about what constitutes the huge chunk of mass in the universe that is not directly visible.
While numerous theories have been proposed, researchers have yet to confirm a definitive explanation for this elusive substance.
Advanced instrumentation has now sparked renewed attempts to uncover possible signals from dark matter in the near infrared spectrum.
After reviewing recently collected data, scientists are discussing results that appear to set new standards on how long certain dark matter particles can last.
Understanding dark matter – the basics
Dark matter is the mysterious, invisible glue that holds the universe together. Most scientists believe it’s there because of its gravitational pull on galaxies, but they can’t see or touch it.
Unlike regular matter, dark matter doesn’t emit, absorb, or reflect light, making it impossible to detect directly.
Instead, astronomers study how galaxies move and rotate – without dark matter’s extra gravity, they should be flying apart.
The crazy part? Dark matter makes up about 85% of the universe’s total mass, yet we have no idea what it actually is.
Scientists are on a mission to crack the dark matter mystery, using massive underground detectors and powerful telescopes.
Some theories suggest it’s made of undiscovered particles, while others think it could be linked to hidden dimensions.
Whatever it is, most scientists believe that dark matter plays a huge role in shaping the cosmos, influencing everything from galaxy formation and black holes, to the structure of the universe itself.
Dark matter signals in infrared light
Associate Professor Wen Yin from Tokyo Metropolitan University has worked with a team on a fresh approach that searched for faint signals produced by axionlike particles.
They relied on the fact that certain theoretical models predict these particles will emit narrow bands of light when they decay.
“The identity of dark matter has been a mystery in astronomy, cosmology, and particle theory for about a century,” wrote Yin and co-authors from Tokyo Metropolitan University in a new study.
They used an infrared spectrograph, known as WINERED, which picks up subtle features in light that might reveal how dark matter decays.
Using infrared tools to detect dark matter decay
Instruments like WINERED, the James Webb Space Telescope, and other devices help scientists inspect complicated electromagnetic signals in the cosmos to see if anything stands out.
Researchers are particularly keen on the near infrared band because some dark matter models point to that range as a possible hotspot.
Investigating this spectral window is tricky because noise from zodiacal light and atmospheric interference can obscure important features.
A new data analysis technique, which separates narrow decay signals from broad background emissions, reduces this confusion.
Mapping hidden galaxies
The Magellan Clay Telescope in Chile measures about 21 feet (6.4 meters) across, and has the ability to capture even the faint glow from distant dwarf galaxies.
By pointing this telescope at galaxies named Leo V and Tucana II, Yin’s team managed to gather significant infrared data in just four hours.
Their measurements pointed to no noticeable bursts at certain frequencies, which suggests that axionlike particle decay was not observed.
The absence of any distinct signal implies that these particles, if they exist, might survive for more than 1025 seconds, which is many times the age of our cosmos.
Signs of something unexpected
Although the data so far show no conclusive dark matter decay, there were slight hints of unexplained patterns that deserve further investigation.
Such anomalies might indicate that more sensitive instruments or longer observation windows could finally pin down a genuine dark matter signature.
Several groups worldwide are refining spectrometers to explore these curious signals at higher resolution.
Continued monitoring of galaxies with low background interference could clarify whether these faint clues are actual traces of dark matter or just simple flukes.
Challenges in detecting dark matter signals
Examinations of background radiation remain complicated because the universe is filled with scattered light from multiple sources.
Researchers must also untangle contamination from Earth’s own atmosphere, which intensifies when the sun heats the air.
Despite these obstacles, improved calibration methods and collaborative efforts between astronomers and particle physicists continue to enhance the search for hidden cosmic matter.
No single test has delivered a decisive answer, yet confidence is growing that bigger discoveries lie ahead.
Why these findings matter
If axionlike particles do show up, they might solve a puzzle that has preoccupied scientists since the 1930s.
Decades ago, measurements of galaxy rotation speeds revealed invisible mass exerting gravitational influence, which prompted the name “dark matter” for this puzzling substance.
Pinpointing whether these elusive particles exist could also unlock new physics beyond the current understanding, and pave the way for novel insights about the structure of the cosmos.
Scientists remain motivated to analyze more data from advanced spectrographs as the chase continues for clues about what really makes up the bulk of our universe.
The study is published in Physical Review Letters.
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