Physical Transformation AtlasPTA
Phenomenon · phenomenon:radiative-cooling

Radiative sky cooling

A surface emitting strongly in the 8–13 µm atmospheric window and reflecting sunlight cools below ambient air temperature, even at noon, by radiating to space at ~3 K.

Optics and photonicsfirst reported 1975also: passive radiative cooling, sky radiation

Atlas record: 6 claims reference this phenomenon — 3 replicated, 2 established and 1 demonstrated.

Explorerelations · matrix context · routes · sources · cite

6claims60enumerated routes2routes with complete-composition evidence20candidate routes not searched4cited sources

Relations

drives · 1
Radiative imbalance with the sky—drives→Radiative sky coolingreplicated
  • an emitter with high emissivity in the 8–13 µm window and high solar reflectance
  • a clear sky; humidity and cloud close the window
produces · 1
Radiative sky cooling—produces→Temperature gradientreplicated
  • the cooled surface sits a few kelvin below ambient air
converts into · 1
Radiative sky cooling—converts into→Coolingreplicated
member of · 1
Radiative sky cooling—member of→Photothermalestablished
implemented by · 1
Radiative sky cooling—implemented by→Radiative-cooling thermoelectric generatordemonstrated
bounded by · 1
Radiative sky cooling—bounded by→Radiative cooling power boundestablished

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

Enumerated routes through this · 60 (showing 24)

Cited sources · 4

  1. [1]
    A. P. Raman et al.. Passive radiative cooling below ambient air temperature under direct sunlight (2014)
    Nature 515, 540–544 · doi:10.1038/nature13883 · crossref ✓ 2026-09-19 · record
  2. [2]
    A. P. Raman, W. Li, S. Fan. Generating light from darkness (2019)
    Joule 3, 2679–2686 · doi:10.1016/j.joule.2019.08.009 · crossref ✓ 2026-09-19 · record
  3. [3]
    J.-l. Kou et al.. Daytime radiative cooling using near-black infrared emitters (2017)
    ACS Photonics 4, 626–630 · doi:10.1021/acsphotonics.6b00991 · crossref ✓ 2026-09-19 · record
  4. [4]
    Y. Zhai et al.. Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling (2017)
    Science 355, 1062–1066 · doi:10.1126/science.aai7899 · crossref ✓ 2026-09-19 · record

Cite this entity

Physical Transformation Atlas (2026). entity phenomenon:radiative-cooling: Radiative sky cooling. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/phenomenon/radiative-cooling

Ids and matrix addresses are stable across revisions; the revision hash identifies the exact canonical files the record was compiled from and is meta.data_hash in every /api export. Reuse terms: see the license field in any export.