|Mars has fascinated people since
the ancient Babylonians, Romans, and Greeks noticed that some of stars
in the night sky were "wanderers" and moved relative to the background
stars. This is because the planets orbit the Sun (as does the Earth) and
are much closer to us relative to the stars in our galaxy. We can see their
movement around the Sun over time.
The planets all appear to move along the same path as the Sun does in our sky. This is because all of planets in our solar system travel the same plane. It is called the plane of the ecliptic. Click here for an interactive view of our solar system.
As seen in the night sky, planets do not twinkle like stars do. This is because planets are very close compared to stars and the reflected sunlight coming from them is very bright. The stars that we can see from Earth are many trillions of miles away and, as their faint light enters our thick atmosphere, their light becomes distorted and "twinkles."
The closest star to Earth is Alpha Centauri, which is 4.3 light years away. A light year is 9.46 trillion kilometers away. That makes Alpha Centauri about 40.1 trillion kilometers away. Depending upon where Mars and the Earth are in their orbits around the Sun, Mars can be as close as 56 million kilometers away and as far as 399 million kilometers away.