Yes, all the planets are constantly in orbit and use up no energy because in space there is nothing to slow them down.
These are called the "terrestrial planets" or "inner planets". They are Mercury, Venus, Earth and Mars.
If planets had no orbital momentum, the gravitational pull from the Sun would pull them into the Sun. Essentially, an orbit is a stable path where an object is constantly falling towards its primary and constantly missing.
Planets orbit stars.
No. Planets orbit suns, while moons orbit planets. Planets do not orbit planets.
The planets orbit because of gravity and their momentum. They are constantly flying away from the sun, but at the same time are being pulled toward it by gravity. The end result is that they stay moving in a circular motion around the sun.
the inertia pulls planets out and gravity pulls them in; the force of each of these makes us constantly orbit. There is a long complex answer to this called General Relativity (a theory put forward by Albert Einstein), but in short they orbit because of the gravity of the Sun as described above.
The 8 planets continue to orbit the sun due to a balance between the sun's gravitational pull and the planets' forward motion, which creates an elliptical orbit. This balance allows the planets to constantly move around the sun in a stable manner.
As of now (late 2013), over 700 planets have been found to exist in orbit around other stars, and more are constantly being discovered.
The Sun has no moons. Moons orbit Planets > Planets orbit the Sun.
The planets do not orbit the Earth, they orbit the sun.
Moons orbit planets. Planets orbit stars. Some stars orbit other stars, or orbit their mutual center of gravity. Stars orbit the center of the galaxy. Galaxies may orbit the center of the "galactic group".
Yes all planets have a orbit