STORMS ON THE SUN.
The Sun does not seem to change his shape as the Moon does.
Looking upon him from our Earth, we see always a round shining body.
Except when part of him is hidden because it has sunk below the horizon
we never have a “half-Sun,” or a “quarter-Sun.”
Sometimes he is high and sometimes low in the sky; but this is brought
about by the Earth’s movements, not by any alteration in himself.
Sometimes clouds drift between and hide him from us; yet behind the
clouds he shines still. Sometimes mists arise and dim his radiance; but
beyond the mist his glory is the same. When clouds move on and mists
fade, the dazzling globe of light is found unchanged.
There are no shadows on the Sun, like those dull markings which we all
know so well upon the Moon.
No shadows, only spots. Yes, the Sun actually has little black spots
upon his face, not so very unlike the tiny patches with which ladies
used to adorn themselves.
A word of warning here! It is not safe to gaze straight at the Sun,
trying to find these spots. When he is low down in the horizon, just
before setting, he is not so dazzling, but at other times one ought to
be very careful. If you want to look steadily at the Sun you should
always use a piece of smoked or tinted glass to soften the glare.
Without this you might hurt your eyes, or even in time make yourself
blind. When looking through a telescope the danger and the need for
care are doubly great.
Dark spots on the Sun are very often to be seen; sometimes only through
a telescope, but now and then one is large enough to be seen with no
such help--by the eye alone.
It was by means of these spots that the Sun was first found to spin
upon its axis, just as our Earth does.
A black spot would be noticed upon one side of the Sun’s face. It would
be seen slowly to cross over, and to disappear on the other side.
Nearly a fortnight would be needed for the journey across, and for
another fortnight, or nearly so, the spot would be hidden behind the
Sun. After which it would turn up again, on the same side as at first,
and in the very same place. Then once more it would travel across and
disappear, and in another fortnight it would come round over to its
starting-point.
If only a single spot had behaved in this way it might have meant
little. But when numbers of spots did the very same thing, time after
time, it became clear that the great body of the sun was whirling
round, carrying the spots with it.
The Sun, like the Earth, has a north pole, and a south pole, and an
equator.
We give the name “north pole” to one end of the axis or line on which
he spins, and the name “south pole” to the other end of that axis. And
we give the name “equator” to a line exactly round the middle of the
Sun, half-way between his two poles.
Most of the spots which we see are somewhere near the Sun’s equator,
not very near to his north pole or to his south pole.
They come and go and change their shapes, and get bigger or
smaller--sometimes slowly, sometimes very fast. A spot may appear and
grow and vanish again in one day, or it may stay on for days and weeks,
and even months, hardly altering at all, only journeying round and
round the Sun.
These things show us that the great Sun spins round upon his axis: and
that for each spin he takes about twenty-five or twenty-six days.
But the whirling round of the Sun means no Day and Night by turns to
him, for the whole of the Sun is always light--bright with his own
radiance.
Once upon a time it used to be thought that the Sun spots were perhaps
_raised_ things--dark objects standing high, like mountains. And I will
tell you why this idea was given up.
Take an empty cup, and hold it before your eyes, with the open part
turned full towards you. The cup must be held as if lying on its
side--not with the mouth upwards, as it would stand on a table. You can
see, thus, the full circle of the opening, and the whole empty inside.
Next, move it a little way to the right from before your face, turning
it slightly away, and you will then see no longer the whole inside, but
only a part: and the round opening will have an oval look.
Turn it still further, and you will see a very narrow oval opening, and
hardly any of the inside.
Now this is just how the spots seem to behave as they cross the Sun.
When first seen, coming round on one side, they are in shape, more or
less, of narrow ovals, and very little of the inside can be seen. As
they travel on with the spinning Sun, and get near the middle of the
Sun’s face, the oval openings widen and grow round, while more of the
dark depths can be seen. Then, passing to the farther edge, they again
grow narrow, as at first.
So we feel sure that the spots are hollows or caves, not mountains.
I do not mean such hollows and caves as are found on the earth, but
more like the holes that may be seen in a mass of stormy clouds. They
seem to be huge rents in glowing Sun-clouds. Usually they have a black
centre, with a gray border round the blackness. Now and then, as in the
picture of a sun-spot given in this book, the gray part is wanting.
Sun-spots are sometimes larger, sometimes smaller; but none that we see
at this distance can be really small. Fifty or sixty thousand miles
across is a very common size. Once in a while a spot is more than a
hundred thousand miles from edge to edge.
So, though we talk of _little_ black spots on the Sun’s face, they are
not really little, but exceedingly big. And if we were near they would
not look black, but fiery.
The Moon’s craters seemed big when we first thought of them--fifty or
one hundred miles across; very huge beside our tiny Earth craters.
These crater-like hollows, however, in the Sun’s cloudy surface are
fifty or one hundred _thousand_ miles across! The whole Moon dropped
into such a hole as this would be a mere little ball in a corner.
The Sun is enormously heavier than our Earth, because enormously
bigger. Yet in actual _make_ the Sun is light. Instead of being all
through as solid as our little Earth, he only weighs as much as if made
of something not much heavier than water.
We do not know whether any part of the Sun is really solid and firm.
Perhaps not even the innermost parts of that vast globe, certainly not
any of the outermost parts. For the heat must be so awful as to turn
everything there into gases. Not cool gases, but raging fiery gases,
rushing furiously to and fro.
Over the whole brilliant body of the Sun is spread a mighty ocean--not
of cool water, like our seas, but of crimson fiery gas-waves. And out
of this ocean spring crimson mountains of fiery gas. And beyond these
jagged mountains--little, as seen from the Earth, but really of great
height--lies a beautiful and wide-spreading wreath of pearly light,
called “The Corona,” or, “The Crown.”
The bright face of the Sun and its tiny black spots can be easily seen
from the Earth. But the crimson sea, showing as a red border round the
edge, and the fiery mountains, and the crown of light, are very seldom
to be seen.
When an eclipse of the Sun happens, then for a few seconds they are
clearly visible to people with telescopes.
Besides the black spots and the red mountains, bright white spots are
sometimes noticed.
Also another curious sight is often seen, in a telescope. Countless
little long narrow objects, something like willow leaves or grains of
rice, seem to lie scattered closely over the sun. They are either side
by side or crossing one another. Look at the picture of the sun-spot,
and you will see the “willow leaves” there. Perhaps they are shining
sun-clouds.
Awful storms are common on the Sun, and terrific outbreaks are often
taking place. Wild rushes of blazing gases can be seen, even from
this great distance. The black spots are most likely caused by vast
whirlwinds tearing open the Sun’s bright envelope of clouds; and the
white spots may be another kind of tornado.
Doubtless the crimson fire-mountains are also some sort of storm. They
come and go, change and disappear, in a longer or a shorter time. Fifty
thousand miles of height is common for one of them, and a hundred
thousand miles is not unusual, and often they are still more.
Our very highest mountain on the Earth is only about seven miles high.
Think what a difference!
But you must not picture to yourself solid mountains of rock on the
Sun. All rock there is not melted only, but turned to gases, by the
tremendous heat. These crimson heights are of gases, glowing and
brilliant.
It is pretty safe to say of the Sun, as of the Moon, that people such
as we are could not possibly live there. If the Moon is too cold,
the Sun is infinitely too hot. If the Moon has no air, the Sun has
certainly none of the right kind for men and animals to breathe.
Besides, how could they exist on a globe of fiery gases?
We know pretty well what the burning power of the Sun is, even here, on
a hot summer’s day, as he shines out of a cloudless sky. But this is
ninety-two millions of miles off!
Imagine what the desperate heat and glare must be at a distance of only
a few thousand miles; not to speak of close to the Sun!
If our Earth were to journey to a place in the sky as far away from the
Sun as our Moon is now from us, one of those fiery mountain-tongues
of crimson gas might leap out and wrap itself round the whole Earth.
But long before she could get so near she would have become a tomb of
death--scorched, and dried up, and withered. The seas would all have
turned into hot steam, and not a blade of grass would be left.
Yet, although, if we could venture near, we should be destroyed, on
the other hand we owe much to the Sun. Did you ever think what a dark
and cold and lifeless globe our Earth would be without him?
All our light, except a few star-glimmers, comes from the Sun. Even
moonlight is really reflected sunlight.
Almost all our heat comes from him. Once upon a time the Earth was hot
and glowing, and some heat still remains deep underground even now. But
this heat could do little for us if the Sun were absent. You know how
icy-cold the ground becomes in winter.
Still, you may say, we have fires to warm us, and lamps and candles to
give us light.
But how could we have either without the Sun? His rays cause the trees
to grow from which we obtain our wood. His warmth in the long past made
those forests grow which were afterwards buried under ground and became
coal. When we burn coal and wood they give out again the heat which
once they borrowed from the Sun.
Without the Sun there could be no oil for lamps, no tallow or wax for
candles. Nothing would live, nothing would grow. Our Earth would be a
dead world like the Moon, fixed and changeless.
True, the Sun shines upon the Moon as upon us; and there he can do
little, because air and water are wanting. _With_ air and water for
his useful servants he can do much. But air and water without the Sun
could do nothing at all--in fact they would be air and water no longer.
So we can trace gratefully to the Sun all the heat, the glow, the
light, the life, the growth, that we find on Earth. And one step
farther brings us to the thought of OUR FATHER IN HEAVEN, who created
the Sun, and who appointed it to be our storehouse of Heat and Light.
QUESTIONS.
1. Has the Sun phases like the moon?
No, he always appears round in shape.
2. Has the Sun gray markings?
No, but he has dark spots.
3. Are the spots large, or small?
They seem small to us at this distance, but they are really large.
4. What size are they?
Fifty thousand miles across, or a hundred thousand miles across, are
not uncommon.
5. How was the Sun first found to spin round?
By the movement of spots across his face, from one side to the other.
6. What is the length of the Sun’s spin?
He spins on his axis once in about 25 or 26 days.
7. Where are spots more often seen?
Not far from the Sun’s equator.
8. Do the spots remain long?
A spot sometimes comes and goes in one day. Other spots stay for weeks,
and even months.
9. What are the spots believed to be?
Holes torn by storms in the Sun’s covering of bright clouds.
10. Is any other kind of storm seen on the Sun?
Sometimes white spots are seen.
11. Is the Sun heavy in make, or light?
Not much heavier than water.
12. What can be seen in an eclipse which is not seen usually?
A crimson ocean of gases, mountains of fiery gases, and the “Corona,”
or Crown of light.
13. How high are the gas-mountains?
Sometimes fifty thousand or a hundred thousand miles high.
14. Are they always the same?
No; they come and go and change, like the black spots.
15. Is it likely that men could live on the Sun?
It seems quite impossible, the sun being in a state of raging heat.
16. Do we owe much to the Sun?
All our light and heat. Without the Sun our world would be a dead
world.