That is, as the planet travels deeper into space, it is getting colder and colder in the diminished sunlight.
By showing that Venus had moonlike phases, he made a strong case that at least this one planet traveled around the Sun.
Each planet travels in an almost round orbit around the Sun.
The bit the planets were travelling through would spin "about" as fast as them, but where "about" is still +/- a sitemap of velocity.
When a planet travels eastward in relation to the stars, it is called prograde.
When the planet travels westward in relation to the stars (opposite path) it is called retrograde.
The planets travelled along overhead rails, powered by electric motors: the orbit of Saturn was 11.25 m in diameter.
The planet, informally named Cochran-A for its co-discoverer, travels an unusual orbit.
From early calculations, the astronomers reported that the planet was traveling a circular orbit around the star once every 3.523 days.
It was, in relation to itself, travelling through space in the same manner as ordinary stars and planets travelled.