Comments on: A Matter of Time https://blog.speculist.com/space/a-matter-of-tim.html Live to see it. Thu, 16 Dec 2021 08:21:00 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: Karl Hallowell https://blog.speculist.com/space/a-matter-of-tim.html#comment-63 Karl Hallowell Wed, 29 Sep 2004 15:30:50 +0000 http://localhost/specblog/?p=74#comment-63 The Economist neatly sidesteps the issue, but in general “Earth-like” just means within a zone of a star (or multiple stars/brown dwarf/gas giant system) where the planet receives enough heat/light that liquid water can exist and where the planet has a mass within a certain range of one Earth mass. As I understand it, Venus, Earth, and Mars are all “Earth-like” though Venus may be too close to the Sun to be considered “Earth-like”.

Europa may be considered “Earth-like”, despite lying well outside the “habitable” zone of the Sun. I don’t know if they consider tidal heating and radiative heating from the brown dwarf or gas giant.

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