Earth-class planet
A planet having a mass 0.5 to 10 times that of the Earth (Me)
and a radius 0.8 to 2.2 times that of the Earth. Planets more massive than
10 Me have enough gravity to attract a large hydrogen-helium
atmosphere and so become gas giants. Those
less massive than 0.5 Me are likely to lose any potentially
life-supporting atmosphere because of low gravity and lack of plate
tectonics needed to recycle carbon dioxide back into the atmosphere.
Archived news
Plenty of Earths
await discovery (Apr 5, 2004) Smallest
'Earth-like' planet seen (Aug 25, 2004) Galaxy
teeming with Earths argues astrophysicist (Feb 19, 2001)
Related categories
EXTRASOLAR
PLANETS AND SUBSTELLAR OBJECTS
PLANETS AND MOONS
• ASTROBIOLOGY
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