27. Q. What planets have been discovered that revolve around the sun outside of the orbit of the earth? A. Mars, asteroids, Jupiter, Saturn, Uranus, and Neptune.
28. Q. What is the mean distance of Mars from the sun? A. One hundred and forty-one million miles.
29. Q. How does the axial revolution of Mars compare with that of Mercury, Venus, and the earth? A. It is nearly the same.
30. Q. What is the diameter of Mars in round numbers? A. Four thousand miles, or one-half that of the earth.
31. Q. What is the appearance of Mars to the naked eye? A. It is the reddest star in the heavens. Sometimes it scintillates, and sometimes it shines with a steady light.
32. Q. How many satellites has Mars? A. Two.
33. Q. When and by whom were they discovered? A. In August, 1877, by Prof. Hall, of Washington, D. C.
34. Q. How many asteroids have been discovered up to the present year? A. Two-hundred and twenty-three.
35. Q. What is the distance of the asteroids from the sun? A. From two hundred million to three hundred and fifteen million miles.
36. Q. What are the diameters of the asteroids? A. From twenty to four hundred miles.