A team of researchers has discovered how polycyclic aromatic hydrocarbons (PAHs), essential for life, can withstand extreme conditions in space. Using data from the James Webb Space Telescope (JWST), scientists found that these organic molecules survive intense radiation and cosmic rays by emitting light through a process called recurrent fluorescence.
Unlike previous theories, this study revealed that PAHs don’t break apart when exposed to high-energy particles but instead dissipate excess energy through this fluorescent emission. This mechanism is key to their survival in space.
PAHs are found throughout the galaxy, holding up to 10% of the carbon needed for life. They have unique infrared signatures, which can be detected using radio and infrared emission astronomy. The JWST has confirmed that PAHs are widespread, with closed-shell molecules in dark clouds and ionized counterparts in brighter regions.
The researchers used a specialized laboratory experiment to simulate interstellar conditions. They found that the indenyl cation, a specific type of PAH, cooled down efficiently through recurrent fluorescence, which is more effective than previously thought.
This breakthrough helps explain why PAHs are more abundant in space than expected. The findings provide essential insights for improving models of interstellar chemistry.
Source: https://phys.org/news/2025-06-recurrent-fluorescence-molecules-survive-extreme.html