relative orbit
61Planetary habitability — is the measure of a planet s or a natural satellite s potential to develop and sustain life. As the existence of life beyond Earth is currently uncertain, planetary habitability is largely an extrapolation of conditions on Earth and the… …
62Dwarf planet — Not to be confused with Minor planet. Ceres as seen with the Hubble Space Telescope. It is the only dwarf planet in the asteroid belt …
63Sun — This article is about the star. For other uses, see Sun (disambiguation). The Sun …
64Precession (astronomy) — In astronomy, precession refers to the movement of the rotational axis of a body, such as a planet, with respect to inertial space. In particular, it refers to the precession of the Earth s rotational axis, also called the precession of the… …
65Milky Way — This article is about the galaxy. For other uses, see Milky Way (disambiguation). Milky Way galaxy Image of the Milky Way s Galactic Center in the night sky above Paranal Observatory Observation data …
66eclipse — eclipser, n. /i klips /, n., v., eclipsed, eclipsing. n. 1. Astron. a. the obscuration of the light of the moon by the intervention of the earth between it and the sun (lunar eclipse) or the obscuration of the light of the sun by the intervention …
67global warming — an increase in the earth s average atmospheric temperature that causes corresponding changes in climate and that may result from the greenhouse effect. [1975 80] * * * Potential increase in global average surface temperatures resulting from… …
68Lagrangian point — The Lagrangian points (IPA en|ləˈgreɪndʒiən, IPA fr|lagʁɑ̃ʒjɑ̃; also Lagrange point, L point, or libration point), are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary… …
69Tide — This article is about tides in the Earth s oceans. For other uses, see Tide (disambiguation). Tidal redirects here. For other uses, see Tidal (disambiguation). High Tide redirects here. For other uses, see High Tide (disambiguation) …
70Escape velocity — In physics, escape velocity is the speed where the kinetic energy of an object is equal to the magnitude of its gravitational potential energy, as calculated by the equation,:U g = frac{ Gm 1m 2}{r}.It is commonly described as the speed needed to …
