ONE HUNDRED QUESTIONS AND ANSWERS ON “RECREATIONS IN ASTRONOMY,” FROM
CHAPTER VIII TO END OF BOOK.
By ALBERT M. MARTIN, GENERAL SECRETARY C. L. S. C.
1. Q. How many primary planets have been discovered between the sun and
the earth? A. Six; four planetoids, Mercury and Venus.
2. Q. When and by whom were the four planetoids discovered? A. In 1878,
during a total eclipse of the sun, Prof. Watson, of Ann Arbor, Mich.,
and Lewis Swift, the famous comet-finder, each discovered two small
bodies within the orbit of Mercury.
3. Q. What is the distance of these planetoids from the sun? A. About
thirteen million miles.
4. Q. What is the time of their orbital revolution? A. About twenty
days.
5. Q. What is the mean distance of Mercury from the sun? A. Thirty-five
million miles, in round numbers.
6. Q. What is the diameter of Mercury in round numbers? A. Three
thousand miles.
7. Q. How does its axial revolution compare with that of the earth? A.
It is nearly the same.
8. Q. With what kind of a light does Mercury shine? A. With a white
light nearly as bright as Sirius.
9. Q. In what part of the heavens is Mercury to be seen? A. It is
always near the horizon.
10. Q. What is the distance of Venus from the sun, in round numbers? A.
Sixty-six million miles.
11. Q. How does its diameter compare with that of the earth? A. It is
nearly the same.
12. Q. How does its axial revolution compare with that of the earth? A.
It is also nearly the same.
13. Q. What is said of the appearance of Venus in the heavens? A. It is
the most beautiful object in the heavens, and is often visible in the
day time.
14. Q. What is the mean distance of the earth from the sun? A.
Ninety-two million five hundred thousand miles.
15. Q. What is the polar and what the equatorial diameter of the earth?
A. The polar, 7,899 miles; the equatorial, 7,925½ miles.
16. Q. State three facts in regard to the aurora borealis. A. It
prevails mostly near the arctic circle rather than the pole; it is
either the cause or the result of electric disturbance; it is often
from four to six hundred miles above the earth, while our air can not
extend over one hundred miles above the earth.
17. Q. What is the cause of tides? A. The attractive force of the moon
and sun.
18. Q. What shores have the greatest tides? A. All eastern shores have
far greater tides than western.
19. Q. What is the mean distance of the moon from the earth? A. Two
hundred and forty thousand miles.
20. Q. What is the diameter of the moon in round numbers? A. Two
thousand miles.
21. Q. What is the time of its revolution about the earth and of its
axial revolution? A. Twenty-nine and one-half days.
22. Q. How clearly do the best telescopes we are now enabled to make
reveal the moon? A. No more clearly than it would appear to the naked
eye if it were 100 or 150 miles away.
23. Q. What is said about the moon presenting the same side to us? A.
The moon always presents the same side to the earth.
24. Q. What is the difference of heat on the moon in the full blaze of
its noon-day and midnight? A. No less than five hundred degrees.
25. Q. What is said as to the presence of air and water on the moon? A.
There are no indications of air or water on the moon.
26. Q. What is said of the maps of the side of the moon toward us? A.
They are far more perfect than those of the earth.
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.