(astronomy, celestial mechanics) An imaginary celestial body (corresponding to another, real, orbiting one) which orbits with constant speed along an auxiliary circle (a circle which shares a diameter with the major axis of the elliptical orbit of the corresponding real celestial body), such that its position coincides with the position of the corresponding, real celestial body when that body passes through periapsis.

(astronomy) a body comparable to a planet, but not a planet, such as a dwarf planet or a planetary-mass moon

(astronomy) A planet composed primarily of metals and/or silicate rocks and having a solid surface.

There is only one Earth, so humans must do everything they can to conserve Earth's environment now, i.e. by taking steps to mitigate climate change, etc.

(astronomy) A hypothetical type of planet resulting from the atmosphere and outer layers of a gas giant being stripped away, leaving the rocky, metallic core.

(broadcasting) The deliberate inclusion in broadcast media of messages warning about climate change or promoting environmental sustainability.

Alternative form of hamplanet

Alternative form of exoplanet

A device for converting reciprocating motion to rotary motion, used in the first rotative beam engines.

plural of sun and planet gear