except when passing through Earth's shadow during a lunar eclipse, always illuminated by the Sun, but from Earth the visible illumination shifts during
also called pure colors or spectral colors. Visible wavelengths pass largely unattenuated through the Earth's atmosphere via the "optical window" region
Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one
structure visible from space, is difficult to discern from even low earth orbit and can require very good viewing conditions. Whether an object is visible depends