We Resume Our Voyage-the Sun And The Sky As Seen From Space

: To Mars Via The Moon

All the time the Areonal had been near the moon some of our machines

were storing up fresh power, and we had accumulated a supply amply

sufficient to meet any extra requirements in the event of our arrival

upon Mars being unduly delayed.



We now turned and looked back at the earth; and, as the moon was so near

to it at that time, the earth's disc appeared very nearly two degrees in

diameter, or near
y four times the usual apparent diameter of the full



moon as seen from the earth. The crescent of light on its right-hand

side was rather wider than when we last looked at it; but so many clouds

hung over it, that we could not see what countries were comprised in the

lighted portion of its surface. Owing to the light of the stars behind

the earth being diffused by the dense atmosphere-in the same way as it

would be diffused by a large lens-there was a ring of brilliant light

like a halo all round the earth's disc.



Having passed away from the moon, I now gave M'Allister the necessary

directions in order to keep the Areonal on a course which would enable

us to head off the planet Mars at, as near as I could reckon, the point

it would reach in fifty days' time. The course having been set,

M'Allister was free to join us again, as the machinery required very

little attention.



When he did so, M'Allister at once asked me a question. "Professor, can

you tell me when it's going to be daylight? The sun has been shining for

hours and hours, yet it's still night; the sky is blacker than the

blackest night I ever saw, and the stars are all out!"



John laughed heartily, and said, "M'Allister, this is daylight! and all

the daylight you will get until we reach Mars."



M'Allister turned to me with a perplexed look on his face and asked, "Is

that right, Professor, or is he trying to pull my leg, as he said he

would?"



"Oh yes! It's quite right, M'Allister," I replied. "It is now full

daylight, and we shall have no more night until we reach Mars. That, as

you know, will be seven weeks from the present time."



"Well, Professor," he exclaimed, "then how is it the sky is so densely

black and the stars all shining so brightly? I never saw the stars in

the daytime before, yet these are shining brighter than they do on the

earth at night."



"Simply," I said, "because upon the earth we were surrounded by a dense

atmosphere, which so diffused the sun's light that the whole sky

appeared bright. The stars were there all the time, but their light was

so overpowered by the brilliancy of the atmosphere that they were quite

invisible to us.



"Now, we are out in space where there is no atmosphere at all, so the

sky appears a very dense black; and the stars, having nothing to obscure

their light, shine out more brilliantly than they do on the earth. They

appear as bright points of light, and even the sun does not shed a

general light over the sky, there being no atmosphere to diffuse it."



"Yes," he persisted, "but you said we should have no more night until we

got to Mars!"



"Certainly," I answered. "Surely, M'Allister, you must have forgotten

that night is brought about by the earth's rotation on its axis, and

that the part which is turned away from the sun is in darkness because

its light is hidden by the solid body of the earth, while the earth's

shadow darkens all the sky. When, by the earth's rotation, that part is

again turned to the sun then it becomes daylight. Remember we are not

now on the earth, but out in space!"



"Of course I did know all that, Professor," he exclaimed, "but, just for

the time, I had forgotten."



"Never mind, M'Allister, we all forget such matters sometimes, and this

is quite a new experience for you. But just take a good look at the

sun-have you noticed any difference in its appearance?"



"Yes, Professor, it doesn't look the same colour as when we saw it from

the earth; it seems to have a violet tinge, like some of the electric

lights in our streets. There are also long streamers of light around it,

and coloured fringes close to the sun!"



"Yes, that is so," I said; "and we can see all those things now because

there is no atmosphere. No doubt you have noticed that on the earth the

sun appeared red when low down in the sky, and during a fog it appeared

redder and duskier still."



"Oh yes, I've often noticed that," he answered.



"That was caused by our atmosphere which, when thick, absorbs all but

the red rays of light. On a clear day the sun appears an extremely pale

yellow, or very nearly white; still the atmosphere absorbs some of the

light rays, so we cannot see its true colour as we do now. Those

coloured fringes round the edges can only be seen from the earth by the

aid of a special instrument, and then they do not show all their true

colours.



"That pearly light all round the sun, and the long streamers that give

it the appearance of an enormous star with six long points, form what is

termed the solar corona, and this can only be seen from our earth during

the very few minutes when an eclipse of the sun is at its totality. It

is to see the corona and other surroundings of the sun, in order to

study them, that astronomers go such very long distances-often

thousands of miles-when there is a total eclipse expected, and not

merely to see the eclipse itself. They hope, in time, to learn much from

such observations; but if it happens that the sky is over-clouded during

the period of total eclipse, then all their expense, and the time spent

in preparations and rehearsals of their procedure, are, unfortunately,

entirely wasted.



"Now, M'Allister, if you will take my glass you will be able to look at

the sun and examine it without any risk to your eyesight, for it is

provided with a dark glass to shut out all the dangerous glare. You will

then see what the fringes and inner and outer coronas really are like."



He took the glass and looked for a long time at the sun, and, judging

from his exclamations of surprise and astonishment, he was extremely

interested and delighted with what he saw. John was also examining it at

the same time through his own glass.



Presently the latter turned to me saying, "Professor, I no longer

wonder that astronomers are prepared to travel long distances, and to

risk a great deal of discomfort, and even hardship, in order to view and

study the sun's surroundings. Of course to them it is not merely a sight

to be seen, but the only means by which they can acquire a knowledge of

solar physics. Merely as a sight, however, it is most wonderful. At many

places all round the edge of the sun's disc I can see what look like

coloured flames-pink, pea-green, carmine, orange, or yellow, all in

incessant movement-shooting out at times, or waving and shimmering in a

manner that is indescribable. The changes in form and colour are as

sudden, yet as definite, as the changes produced by turning a

kaleidoscope; while the intermingling of the various colours frequently

produces an effect which I can only compare to the iridescent colours on

mother o' pearl. Then all around and beyond the coloured fringe there is

the light of the pearly inner corona; beyond that are pearly and

violet-tinged rays curling away in both directions from the poles,

whilst outside all are the long, pearly, and violet-tinted streamers

which assume the shape of a large many-pointed star; and even these do

not seem at rest. Though astronomers cannot see all that we do now,

there must be sufficient visible to them to afford opportunity for a

most interesting study."



"That is indeed the case, John," I replied. "Those coloured flames, for

instance, form a study in themselves, which some observers make their

particular hobby. As seen from the earth, they all appear some tint of

red; and, normally, according to measurements, they seem to extend a

distance of some 20,000 miles above the sun. They shift their position

very rapidly indeed; movements at the rate of 100 miles a second are

quite moderate compared with some which have been noted, yet one can

scarcely realise such rapidity of motion. Frequently, however, these

flames are seen to rise in immense masses to tremendous heights above

the sun's surface, evidently driven upwards by explosions of the most

intense energy. In 1888, for instance, one was observed which, in the

course of two hours, rose to a height of 350,000 miles before it broke

up; that is, at the rate of 50 miles a second all the time; but, as the

force would become less and less as the distance increased, at the

earlier part of the time the movement must have been far more rapid.

When the impetus derived from the explosive force is quite exhausted,

the top part of the mass of flame often spreads out like the top of a

tree, then breaks up and falls back into the sun in large flakes of

flame.



"It is supposed that these violent explosions are the cause of the spots

we so often see on the sun when observing it with our telescopes; and,

when looking at them in their earliest stage, we are probably looking at

a mass of flame end on, instead of seeing it in profile, as is the

case when the explosion occurs near the edge of the disc. The flames, as

examined by the spectroscope, appear to be largely composed of hydrogen

gas; and no doubt many other gases-some quite unknown to us-enter into

their composition. They are termed flames, but are more probably immense

volumes of incandescent gases. The corona itself is never seen twice

alike; its shape and size vary at every eclipse, but the variation runs

in a regular cycle from maximum to minimum.



"You will also observe that all around the corona, and extending a vast

distance beyond it on both sides, is a fainter pearly light. This is

what is termed the zodiacal light, and is believed to be the thinner

portion of the sun's atmosphere. We can see it from the earth

occasionally after the sun has set, extending far up into the sky in the

form of a semi-ellipse, the base of which is over the place where the

sun is."



M'Allister here asked me to tell him "What was supposed to be the actual

size of our sun, and how far it was away from the earth?"



I answered that "The sun is about 865,000 miles in diameter; and that he

would have some idea of what an immense body it is if he remembered that

it would require 64,000,000 globes the size of the moon to make one

globe the size of the sun! Yet, notwithstanding this immense size, our

sun is quite a small body as compared with some of the fixed stars,

which, as perhaps you may know, are really suns at an inconceivable

distance from us. The bright star Sirius, which is visible during our

winter time, is not only very much brighter in reality than our sun, but

must be many times larger; and there are others known to be very much

larger than Sirius. It has been computed that Arcturus is in mass

500,000 times as large as our sun!



"The sun revolves on its axis in a little over twenty-five days, but the

exact period of its revolution is difficult to determine. The mean

distance of the sun from the earth is about 92,800,000 miles. When we

are farthest from it its distance is 94,600,000 miles, and when nearest,

91,000,000 miles-these differences, of course, arising from the

eccentricity of the earth's orbit.



"The sun's density is only about one-fifth of the earth's density; so it

is evidently mainly gaseous-at all events in the outer envelopes.



"The spots upon the sun often cover such an immense area, that if our

earth were dropped into the cavity, it would be like placing a pea in a

teacup! Some of the spots entirely close up in a short time, but others

last for weeks."



We now turned from the sun and looked at the stars. Such a multitude

were visible as we had never seen from the earth; for small stars, which

there required a telescope to bring them into view, could now be plainly

seen without any such aid, and their various colours were seen much more

clearly. They all shone with a clear and steady light; the twinkling and

scintillation of the stars, as seen from the earth, being caused by the

vibrations and movements in our own atmosphere. We also saw many nebulae

without using a glass.



The Milky Way was a most gorgeous spectacle, and its beauty utterly

beyond description, as such an immense number of its component stars,

and their different colours, were visible to the unaided eye; besides,

we could trace wisps and branches of it to regions of the sky far beyond

the limits within which it is seen from the earth.



We noted that the planets were also much more clearly seen; and the

orange-red disc of Mars, of course, received our particular attention.



We had spent very many hours in viewing the moon, and a long time in

examining the sun and stars; so we now sat down to a hearty meal, and,

after a short time spent in conversation, we made our arrangements for

taking turns in attending to the machinery, and then retired to bed.




Planets between the 3rd of August and the 24th of September, 1909: and

the Course taken by the "Areonal" on the Voyage to Mars.



The dotted line joining the Earth to Mars shows the course taken.





The dotted Circles show the Orbits of the Planets. The thick arrows

show the distances travelled by the respective planets during the period

covered by the Voyage: the line at the back end of the Arrow being the

planet's position on the 3rd August, and the points of the Arrows the

position reached on the 24th September.



The Orbits of Mercury, Venus, the Earth and Mars are drawn

approximately to scale, but those of the outer planets are not. On the

same scale, the radii of the Orbits of the outer Planets would,

approximately, be as stated below. These figures will afford some idea

of the enormous distances separating those planets.



Jupiter 3 Inches

Saturn 5-3/8 "

Uranus 10-7/8 "

Neptune 17 "



Drawn by M. Wicks



Plate V]



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