Science Just Found a Hidden State of Water. It Clashes with Physical Limits.

Key Points:

• Scientists have experimentally confirmed that supercooled water can exist in two distinct liquid phases—a high-density and a low-density form—that merge at a critical point under extreme cold and pressure.
• Using an X-ray free-electron laser, researchers observed this liquid-liquid critical point (LLCP) at around -63 degrees Celsius and 1000 atmospheres, overcoming previous challenges posed by rapid freezing.
• This discovery helps explain water’s unique and anomalous properties, such as its density maximum at 4 degrees Celsius and the fact that ice floats, which differ significantly from other liquids.
• The findings validate long-standing hypotheses dating back over a century and open new avenues for understanding water’s role in physical, chemical, biological, geological, and climate-related processes.
• Future research will focus on exploring the broader implications of the LLCP on water’s behavior under various environmental conditions and its impact across multiple scientific fields.