The depth of the hidden sea appears to have been very great, so that the earth's internal heat could ensure its habitability for an indefinite period.
urak epeltasun uniformeagoa bermatzen zielako, zalantzarik gabe. Ezkutuko itsaso hori oso sakona zen, antza, eta, hala, Lurraren barne-beroak bizigarritasuna bermatuko zuen epe mugagabean.