06/09/2026
The Sun Was Too Faint. The Oceans Were Liquid Anyway.
The Sun is about 30% brighter now than when it formed. Run the energy balance backwards four billion years and Earth's average surface temperature comes out below freezing — and below freezing isn't cold, it's a runaway, because ice reflects sunlight, which makes more ice.
So the early Earth should have been a frozen ball. Except we have the rocks.
Pillow lava from Isua in Greenland, 3.7–3.8 billion years old. Pillow lava only forms underwater — that isn't an inference, it's a cast of the water it cooled in. Zircons from the Jack Hills at 4.4 billion years. Stromatolites in the Pilbara at 3.43 billion.
Both sides are right. This episode is about what everyone assumed without checking.
Every number on screen was computed for this video from published constants, with the assumptions shown. Our figures check out against the published values: Earth's radiating temperature comes to 254 K and Mars's to 210 K, matching the NASA fact sheets.
WHAT WE FOUND
• The shortfall is 59 watts per square metre, continuously, for billions of years
• Removing every low cloud on Earth buys you about 25 of those 59 — less than half
• Ammonia was the first proposed fix, in 1972. Ultraviolet light destroys it in years
• A thicker nitrogen atmosphere was the next. Measurements of 3-billion-year-old quartz found the opposite
• The real answer is a thermostat: rock weathering pulls CO₂ down when it's warm, volcanoes put it back when it's cold
• But the Archean was not warm the whole way through — there are ice ages at 2.9 and 2.4–2.1 billion years
• Two authoritative reviews, eight years apart, reach different verdicts on whether the problem is solved
• Mars needed 78°C of greenhouse warming. Earth's entire greenhouse effect today is 34°C