This happened a little later, and soon they could observe the great ball of fire hanging in space.
"It seems to be smaller than when we were on the earth, doesn't it?" asked Mark.
"It is seemingly smaller," replied Professor Henderson. "We are going away from the sun you know. Mars is not as close to it as we are on our planet—I mean the one we have just left—is ninety–two millions of miles from the sun, while Mars is one hundred and forty–one millions of miles away, though its orbit is so eccentric that distance varies about thirteen millions of miles. That is, it may be thirteen millions of miles more than its mean, or average, distance, so that at times it is as far away from the sun as one hundred and fifty–four millions of miles."
"My! That's a good ways," observed Mark.
"Yes," went on Mr. Henderson, "and, in consequence, the light and heat received by Mars from the sun is a little less than half of that which our earth receives."
"Whew! We'll be mighty cold in winter—if we arrive in winter," said Jack with a shiver.
"Unless the Martians have a means of making up for this loss of light and heat," said Mr. Roumann. "I believe they have."
"I shall be much interested in seeing how the great canals on the planet are dug," said Professor Henderson. "I have seen a map of Mars, made by a scientist named Schiaparelli, and he has drawn a number of large bodies of water, among which are intermeshed continents and islands. The surface of Mars must be a curious one."
"I believe we shall find it so," spoke Mr. Roumann. "Astronomers tell us that the water on it is never frozen, except near the poles. There great ice caps are to be found."
"But what makes the planet so red?" asked Jack.