CHAPTER XVIII.. Little Meteors.

LITTLE METEORS.

Meteors are the very smallest bodies of which we know, that float and rush about in the sky.

Besides being the smallest they are also the most abundant. Their numbers are not only past counting, but past our power to imagine.

We cannot see them as they speed hither and thither through the skies, travelling either alone or in tens of millions.

Each one indeed gives forth its tiny light, borrowed from the Sun. But those dim gleams are far too weak to reach us here on Earth. The only time when they can be seen by us is when they come by accident into our air.

Then indeed we do see them--not by the gentle shining which they catch from the Sun, but by one brilliant flash of light as they are destroyed.

It is the rush through our thick air which destroys the meteors. The air always tries to hold back anything moving fast through it.

A meteor far away in the sky is a hard and cold little body--very cold indeed, out in the terrible cold of Space. It has no light of its own to give forth.

And in the sky a meteor goes very fast, rushing round the Sun. When it first gets into our air it keeps up that great speed. The air tries to hold it back; and the rubbing of the air against it heats the outside of the little meteor so intensely that it glows with bright light.

It becomes in fact “white-hot.” The outside melts and pours away in a stream of shining dust, which to us looks like a tail of light. The dust soon cools, and drops gently down upon the ground.

Before the meteor has rushed twenty or thirty miles it is generally done for. All of it has gone off in bright dust, and nothing is left of the tiny heavenly body except that dust.

This is what you see when you look at a “shooting star” after dark. Of course you have seen shooting stars very often. If not, you should begin to look out for them as soon as possible.

A shooting star is no star at all, really. It is only a little meteor, or meteorite, which has travelled for ages in the skies, and which has at last happened to come too near to our Earth. The strong pull of the Earth’s attraction has dragged it into the air, and so it has perished.

Hundreds and thousands of meteors are ever dropping earthward. If it were not for our soft protecting air we should be under a regular cannonade from the sky; but happily most of the cannon-balls are used up long before they can reach the ground.

On the Moon, where there is no protecting air, one would have to undergo a fearful battering.

Now and again a meteor is large enough not to be all destroyed in its rush downwards. A good part is melted, and runs away as a little tail of brightness, but both speed and heat grow less before the whole is gone.

So then part falls to the ground as a solid stone, or as a lump of iron and other metals. We call the fallen lump an “aerolite” or a “meteorite,” or a “meteoric stone.” But it is commonly just a meteor which has come to us out of the sky.

Some very large aerolites have been known to burst in the air with a great noise, and to scatter hot stones over the land below. This sort of thing happens very seldom.

There are wonderful Rings of Meteors journeying round the Sun--enormous companies of millions upon millions of little dark cold bodies, lighted up by the Sun’s rays.

Every August and November our Earth in her journeying touches one such Ring. In those months a great many more “shooting stars” may be seen in the sky than at other times of the year. So, when you want to see shooting stars, remember that the best times are August and November. If then you watch the sky steadily after dark for half an hour you will hardly fail to see at least two or three.

About once in every thirty-three years our Earth plunges into the very thick of one of these Meteor-Rings. And then indeed we may have a splendid sight!

Tens of thousands of meteors can be seen flashing through the air, each with its little train of light behind. Fast as they appear and vanish tens of thousands more follow; and for hours this goes on.

Yet even then the number of meteors which can be seen is as nothing compared with the vast hosts which cannot be seen because they do not come into our air.

Sometimes comets and meteor-rings are found together, journeying in company. That is to say, the comet journeys with the meteors, in the same ring or pathway round the Sun. This really seems to show that the one may belong to the other.

I have told you already that comets, or at least comets’ heads, are believed to be made partly of little meteors. If things are so, one would not be surprised to find a very close tie between comets and rings of meteors.

You will remember Biela’s Comet, spoken of in the last chapter, which some people think has actually broken up into separate meteors.

It is thought very likely that the wonderful Rings of Saturn are entirely made of meteors. Not of bright dying meteors, as we see them in our air, but of countless millions of tiny hard bodies, all whirling together round and round the huge planet, and giving forth such light as they can borrow from the Sun.

Sometimes on the Earth a faint light is seen, of a sugar-loaf shape, in the eastern sky, before dawn, or in the western sky after sunset. It is called the Zodiacal Light, and it plainly has to do with the Sun. It is always seen very near to the Sun, never anywhere else.

We know little about this curious light, but it too may be caused by the shining of enormous numbers of meteors, all whirling round the Sun. No doubt countless multitudes are ever dropping down upon his fiery surface.

Each little meteor that journeys round the Sun shined, like the worlds, on one side only--that side which is towards the Sun.

QUESTIONS.

1. What are Meteors?

The smallest heavenly bodies known to us.

2. How many meteors are there?

Immense multitudes in the sky, beyond our power even to imagine.

3. How do meteors shine when journeying in the sky?

They shine by borrowed sunlight.

4. Does a meteor shine all round?

No; only on that side which is towards the Sun.

5. Do we see meteors by means of that borrowed sunlight?

No; we only see them when they rush into our air.

6. What makes them visible to us then?

They are so much heated by the rubbing of the air as to shine brightly for a moment with their own light.

7. What becomes of such meteors?

The outside is melted and streams behind as shining dust.

8. Does any part of them reach the ground?

Generally they are destroyed in their rush through the air, and only the dust drops downwards.

9. Are they always quite destroyed?

Sometimes a part escapes, if the meteor is rather large, and then a solid lump of rock or metal comes to the ground.

10. What is such a lump called?

A Meteorite, or an Aerolite, or a Meteoric Stone.

11. What is it really?

Part of a meteor from the sky.

12. What do we call a meteor seen only by its last flash?

Either a “meteor” or “a shooting star.”

13. When are shooting-stars most common?

In August and November.

14. Why?

Because our Earth then touches meteor rings, and so a great many come into our air.

15. When does our Earth plunge deep into a meteor-ring?

About once in every thirty-three years.

16. What is seen then?

A most wonderful display of tens of thousands of meteors.