We are now about to take a good look at the moon and examine the
different objects which are marked upon it. There is a peculiar
interest attached to this particular orb, because it is much the
nearest of all the heavenly bodies to our globe, and therefore the one
that we can see the best. Every other object--sun, star, or planet--is
hundreds, or perhaps thousands, of times as far off as the moon. It is
right that we should desire to learn all we can about the bodies in
space. We know that the earth is a great ball, and we see that there
are many other such bodies. Some of them are much larger, and some of
them are smaller than the globe on which we dwell; some of them are
dark bodies like the earth, and among them the moon is one. Is it not
reasonable that we should make special efforts to find out all we can
about this interesting neighbor?
Though the moon is so close to us relatively to other objects in space,
yet when we express its distance in the ordinary methods of measurement
it is a very long way off--about 240,000 miles--a length nearly as
great as that of all the railways in the world put together. An express
train which runs forty miles an hour would travel 240 miles in six
hours, and the whole distance to the moon would be accomplished in
6000 hours, so that travelling by night and day incessantly you would
accomplish the journey in 250 days. To take another illustration, if
you wrapped a thread ten times round the equator of the earth, it would
be long enough to stretch from the earth to the moon. Or suppose a
cannon could be made sufficiently strong to be fired with a report loud
enough to be audible 240,000 miles away. The sound would only be heard
at that distance a fortnight after the discharge had taken place.
The moon is too far for us to examine the particular features on its
surface by the unaided eye. Suppose that there was a mighty city
like London on the moon, with great buildings and teeming millions
of people, and you went out on a fine night to take a look at our
neighbor. What do you think you would be able to see of the great lunar
metropolis? Would you be able to see its streets full of omnibuses, or
even its great buildings? Would you see St. Paul’s and Westminster--the
great parks and the river? Of all these things your unaided eye would
show you almost nothing. I can give you a little illustration. Suppose
that you made a tiny model of London; imagine this little structure
all complete, so that the streets, the buildings, the bridges,
the railways, the parks, and the Thames were placed in their true
proportions; suppose that the miniature city was so small that it could
stand on a penny postage stamp, surely everything would look very
insignificant, even if you had the model in your hand and looked at
it with the aid of a magnifying glass. But suppose it were put on the
other side of the table or on the other side of the room, or the other
side of the street. Even St. Paul’s Cathedral itself would have ceased
to be distinguishable; but yet the distance is not nearly great enough.
You would have to put the little model a quarter of a mile away before
it would be in the right position to illustrate the appearance of a
lunar London to the unaided eye.