Scientists have provided experimental evidence for the existence of a liquid-liquid critical point (LLCP) in supercooled water.[1][2] A study published in the journal Science (vol. 391, no. 6792, pp. 1387-1391, March 2026) demonstrates the transition between high-density lipoprotein (HDL) and low-density lipoprotein (LDL).[1][2] Supercooled water can remain a liquid below 0 °C, but below -50 °C it quickly crystallizes into ice, making experiments difficult.[1][4] Researchers used simulations and experiments that showed the free energy barrier between HDL and LDL vanishing at a critical point.[1][7] The transition took place in the area of high temperatures in the so-called "no-man's land" (pressures and temperatures where only crystallization usually occurs), above the temperatures of amorphous ice.[2] The structure of water changes continuously upon cooling to 1 bar down to 227 K, indicating single-phase behavior without LLT at atmospheric pressure.[2] The results confirm the LLCP hypothesis at positive pressures above 1 bar.[2]