66,000MPH or 107,200 KM/HR
Mars
Mars
Copernicus.
Jupiter
He discovered that the Earth is a moving planet
Gravity.
nothing, as far as I know. The earth isn't moving slow, it's moving extremely fast.
No planet is made of glass, as far as I know. The giant planets - Jupiter, Saturn, Uranus, Neptune - are large, and made mostly of gas. However, they are not fast-moving.The inner planets - Mercury, Venus, Earth, Mars - are slow, fast-moving, and made basically of rock.
It changes every day
Yes, the earth rotates but too fast for us to notice.
A planet isn't retrograde - retrograde means the direction a planet moves in relation to how we see it here on Earth or other perspectives. Planets sometimes appear to move backward due to Earth moving as well.
10km/s