Economy.
Economy.
Free. Always. No paid grades.
FACT is a checkable record. CLAIM is an argument. FAITH is what the Order holds, and does not ask you to treat it as proof.
FACT
No grades for sale.
There is no tier, no price, and no paid advancement. The list, the pages, and the exit cost nothing.
FACT
The habitability window.
The habitability window of the Earth for complex life is about 1 to 1.8 billion years, on the usual estimates of rising solar luminosity.
Source. Caldeira and Kasting, Nature 360 (1992), and later reviews of the biosphere’s remaining span. This is a range, not a date.
FACT
The old name.
The name “six-billion-year test” is not used. The figure on this site is the habitability window, about 1 to 1.8 billion years.