Some planets are actually getting more heat from the gravity 'pull' of their nearby star than they are from the actual sunlight hitting them.
March 26, 2026
Original Paper
A Physical Classification of Exoplanet Thermal Environments: Stellar Irradiation versus Tidal Heating
arXiv · 2603.23557
The Takeaway
We usually assume a planet’s temperature depends on how much sunlight it receives. However, this study reveals that for many worlds, "tidal heating"—the literal squeezing and stretching of the planet's core by gravity—is the dominant heat source, potentially keeping planets warm even in total darkness.
From the abstract
In this study, we introduce a physical framework to analyse and classify the thermal regimes governed by tidal heating and stellar irradiation. Although all planetary systems are exposed to stellar radiation, this source is not always the dominant energy mechanism. This study is motivated by the lack of a physical framework that examines tidal heating in cases where this phenomenon dominates over stellar irradiation. We develop a reproducible physical approach that allows us to classify the rela