e marvellous streamers and filaments? They are what they
seem, eruptions of fiery matter discharged from the ever-palpitating sun
thousands of miles into surrounding space. They are for ever shooting
out and bursting and falling back, fireworks on a scale too enormous for
us to conceive. Some of these brilliant flames extend for three hundred
thousand miles, so that in comparison with one of them the whole world
would be but a tiny ball, and this is going on day and night without
cessation. Look at the picture where the artist has made a little black
ball to represent the earth as she would appear if she could be seen in
the midst of the flames shooting out from the sun. Do not make a mistake
and think the earth really could be in this position; she is only shown
there so that you may see how tiny she is in comparison with the sun.
All the time you have lived and your father, and grandfather, and right
back to the beginnings of English history, and far, far further into the
dim ages, this stupendous exhibition of energy and power has continued,
and only of late years has anyone known anything about it; even now a
mere handful of people do know, and the rest, who are warmed and fed and
kept alive by the gracious beams of this great revolving glowing
fireball, never give it a thought.

I said just now a pale green halo surrounded the sun, extending far
beyond the prominences; this is called the corona and can only be seen
during an eclipse. It surrounds the sun in a kind of shell, and there is
reason to believe that it too is made of luminous stuff ejected by the
sun in its burning fury. It is composed of large streamers or filaments,
which seem to shoot out in all directions; generally these are not much
larger than the apparent width of the sun, but sometimes they extend
much further. The puzzle is, this corona cannot be an atmosphere in any
way resembling that of our earth; for the gravitational force of the
sun, owing to its enormous size, is so great that it would make any such
atmosphere cling to it much more densely near to the surface, while it
would be thinner higher up, and the corona is not dense in any way, but
thin and tenuous throughout. This makes it very difficult to explain; it
is supposed that some kind of electrical force enters into the problem,
but what it is exactly we are far from knowing yet.

CHAPTER VIII

SHINING VISITORS

Our solar system is set by itself in the midst of a great space