“You must remember that the Earth’s moon is about 240,000 miles away from it, while Mars’ nearest moon is only about 3,700 miles above its surface.”
“How high is the other one?”
“Approximately 13,000 miles; but it is doubtful whether it would be visible to the naked eye from Mars—certainly not plainly. The one nearer Mars, however, should present an interesting spectacle from that planet. It requires eleven hours to cross Mars’ heavens, by reason of the moon’s own swift revolution and the slower rotation of Mars, going through all its phases and half again during that time.”
“It’s odd that it doesn’t fall into the planet from that height,” said Robert.
“Rapid revolution in its orbit round Mars produces sufficient centrifugal force to balance the planet’s attraction,” said Professor Palmer. “The same principle is involved as in the swinging of a pail of water over one’s head without spilling it. Yet, some day one of these moons may be drawn into the planet. Should that happen, the blow may be great enough to change the planet’s own orbit.”
“How about landing on one of these moons?” said Robert.
“Ha! Novel thought, that,” exploded Taggert. “Say, if we’d play catchers on it, we would be apt to run right off.”
“I don’t think catchers would be a very good game to play on these moons,” chuckled Professor Palmer. “You see, a person wouldn’t weigh much more than a feather on one of them, and if he took a real good leap on the under side he might find himself on his way to Mars. Not only that; there is no atmosphere on them, and you could not exist an instant in the vacuum and intense cold prevailing there, even if you were equipped with respiration tanks.”
“That’s enough for me,” Taggert decided with a grimace.
“How cold do you think it is out in space like that?” asked Robert.