Two possible complications for habitable zones and elliptical orbits.

Circular orbits are friendly to life, while very elongated orbits result in large seasonal temperature fluctuations.

This circular orbits are also known as the energy levels.

Each of these six orbital planes is spaced sixty degrees apart.

Instead of being placed in circular orbits at stable altitudes, they were stranded in elliptical orbits useless for navigation.

The planets move in circular or elliptical motions.

For all circular orbits around a given central body:

Let us suppose the stars are moving in circular orbits about

A synchrotron is an accelerator in which the magnetic field bending the orbits of the particles increases with the energy of the particles.

Orbite 3 circular orbits at an altitude of 23,222 km

Orbite 3 circular orbits at an altitude of 23,222 km

The electrons revolve only in certain permitted orbits called stationary orbits.

Two orbits later a second burn placed Apollo 8 into a near-circular 110.4 by 112.3 km orbit for eight orbits.

Their orbits are nominally circular with an inclination of about 55 degrees and have a period of 12 hours.

The above diagrams show the relative sizes of the orbits of the nine planets from a perspective somewhat above the ecliptic (hence their non-circular appearance).