Cosmic ipsum ice giant sky crescent moon wavelength transparency conjunction transneptunians mass meteor spectrum gravitational constant gas giant helium parsec singularity eclipse day deep space planetoid Hubble telescope Earthshine aphelion galaxy escape velocity probe local arm solar solar wind vernal equinox observatory geostationary vacuum black body spectroscope gravitation dust local group light-year yellow dwarf space outer planets gravitational lens dark matter Roche limit Mir Bailey's beads perigee inner planets!