He might just as well have been talking about the planet Mars.

This is also where the planet Mars gets its name from.

In 1878, he published his work on the planet Mars.

For there has been too much human killing on the planet Mars.

Half an hour ago they had been in orbit around the planet Mars.

Let us consider the daily motion of the planet Mars.

It was sent to study and orbit the planet Mars.

The planet Mars appears to have had most of the conditions necessary to support simple life forms.

The planet Mars has a surface which is somewhat similar to that of our moon.

The planet Mars is one of the most studied objects in our solar system.