A Narrow Escape From Destruction-i Give Some Particulars About Mars And Martian Discovery
:
To Mars Via The Moon
Things now went on quietly and, in fact, rather monotonously for several
days; and then we met with another rather startling experience.
We were all sitting together in our living-room on the 9th of September,
whiling away the time in a game of whist, and, as it was the final
rubber and we were running very close together, we were quite absorbed
in the play; although, of course, it was a dummy game.
Suddenly we heard a most tremendous crash, apparently from the
right-hand side of the air-chamber, the vessel giving a violent lurch
sideways, then shivering and trembling from end to end. The crash was
immediately followed by a sharp rattling on the top and side of the
Areonal, just as though a fusillade of good-sized bullets had been
fired at us.
"My word! whatever's that?-one of the cylinders must have exploded,"
cried M'Allister, jumping up in alarm and running into the air-chamber.
We followed him, and looked all round the room at the different machines
and apparatus, but could find nothing wrong.
John, chancing to look up, however, at once noticed a large bulge on
the inner shell of the vessel, high up on the right-hand side; and then,
turning to me, pointed it out, saying, "I think, Professor, it is pretty
clear now what has happened."
"Yes, that huge bulge explains itself," I replied; "undoubtedly a
fair-sized meteoric stone has collided with our vessel. It is very
fortunate that the stone was not much larger, or there would have been
an end to the Areonal and to us as well. These meteorites travel at
such tremendous speed that, on entering the earth's atmosphere, they
become incandescent owing to the friction of the air, and, unless very
large, are entirely consumed and dissipated into dust before they can
reach the earth. Those that do fall are always partially fused on the
outside by the tremendous heat generated by the friction of our
atmosphere. These meteorites are what people call 'shooting stars,' and
many are under the impression that they really are stars, until the
difference is explained to them."
John said, "We ought to congratulate ourselves upon such a lucky escape
from annihilation; for had our vessel been constructed of any metal less
hard and tough than our 'martalium,' and without a double and packed
shell, it must have been wrecked and entirely destroyed by the shock of
the tremendous concussion it had sustained. Even the very metal of the
casing might have been completely melted by the intense heat generated
by the impact of the meteorite."
"Heh, mon!" exclaimed M'Allister; "it's all very well talking about our
lucky escape, and putting it all down to your own cleverness in
designing and constructing the Areonal; but you should rather give
thanks to Providence for saving us, and for enabling you to take the
precautions you did. I say, 'Thank God!'" he remarked, and he solemnly
raised his right hand as he spoke.
"Quite right, M'Allister," replied John: "we are all too prone to credit
ourselves with more than we are entitled to. At the same time,
M'Allister, you must remember that we Englishmen recognise as fully as
you do the over-ruling power of Providence, although we may not be quite
so free in speaking about it in ordinary conversation."
"Yes," I added, "you may be quite sure, M'Allister, that we are equally
as grateful as yourself for the mercy which has preserved us all from an
awful death. My very first thought on realising our extremely narrow
escape from destruction was to say 'Thank God!' but I did not say it
aloud as you did. It is in matters like these that people differ
according to their temperament and training; and it is not safe to judge
another because, in any particular circumstances, he does not act in
precisely the same way as we ourselves would."
Thus we travelled on and on, each day bringing us more than two million
miles nearer to our destination. Mars was apparently increasing in
diameter the nearer we drew to it, and the dark blue line around the
south polar snow-cap, indicating the lake of water from the melting
snow, was very conspicuous. The snow-cap had recently decreased rapidly,
being now near its minimum and irregular in shape, for in the southern
hemisphere it was now late in June. Pointing to the planet, I remarked,
"There is our destination! We see it now as the poet pictured it for us,
and the words of Dr. Oliver Wendell Holmes are very appropriate to the
present circumstances:
'The snow that glittered on the disc of Mars
Has melted, and the planet's fiery orb
Rolls in the crimson summer of its year!'"
On the 18th of September we passed between the earth and Mars, nearly in
a line with the sun. On that date Mars was in perigee, or at its nearest
point to the earth during the present year. Its distance from the earth
was then 36,100,000 miles, and it will not be so close again until the
24th of August 1924. We could not see the earth, as its dark side was
turned towards us, and it was also lost in the brilliancy of the sun.
At this date we had travelled 88,000,000 miles since we left the earth,
yet we knew it was there, level with our vessel, and only about
29,000,000 miles distant on our left hand, whilst Mars was only
7,000,000 miles from us on our right-hand side.
Our position now was as follows:-Taking an imaginary line drawn from
the Areonal to Mars as the base line of an isosceles triangle, we were
moving along the left side of the triangle, and Mars was moving in a
slightly curved line along the right side. Our paths were therefore
converging, and if all went well we should both meet at the apex of the
triangle on the 24th September, as we had originally intended.
We therefore had six clear days to cover the distance of less than
12,000,000 miles, so we should have sufficient time to slacken speed at
the end of the journey. (See the chart.)
Mars was rapidly growing in size and brightness, for the distance
between the planet and the Areonal was quickly diminishing as our
paths converged, and the various markings on its almost full round disc
formed the subject of continual observation and conversation. We had
noticed on several occasions a mistiness on some parts of the planet,
which I attributed to the vapours raised from the canals by the heated
atmosphere.
On the 21st of September, when we were all enjoying a smoke in the
"evening," and conversation had dragged somewhat, John started us off on
a fresh tack and gave us something to talk about for a very long time.
He winked at M'Allister and, looking at me with a knowing smile, said:
"Professor, as we are nearing our destination it might perhaps be well
if you now gave us some detailed information respecting the planet,
similar to that which you gave us when we were approaching the moon. It
would be both interesting and useful; for we should learn much more from
an orderly statement of the facts than we should from several long but
desultory conversations."
"Yes, Professor," chimed in M'Allister, "I'm quite ready to learn
something definite about Mars, for I can't say I really know much about
it at present."
"Very well then," I replied, "it is upon your own heads, and if you are
willing to listen to a rather long story, I am prepared to do the
talking. Please remember, however, that it will require some time to
make matters clear and understandable."
"Fire away, mon," cried M'Allister, "we will listen as long as you care
to talk."
So I began-"Mars, as no doubt you are aware, is a much smaller planet
than the earth, its diameter being only 4220 miles, which is a little
less than twice the diameter of our moon.
"It would require nine and a half globes the size of Mars to make one
globe the size of the earth; and even then it would not be so heavy,
because the average density of Mars is only about three-fourths of that
of the earth. Mars is the next planet outside the earth's orbit, so is
the fourth from the sun. The orbit in which Mars moves in its journey
round the sun is very much more eccentric than the earth's orbit; in
fact it is more eccentric than the orbits of any of the larger planets.
As a consequence, the planet's distance from the sun varies greatly
according to the particular part of the orbit in which it may be moving.
Its mean distance from the sun is 141,500,000 miles, its greatest
distance over 154,000,000, and at its nearest approach to the sun, or
'perihelion,' as it is called, its distance is only 129,500,000 miles.
Mars travels in its orbit at a mean rate of 15 miles a second.
"As its orbit is also eccentrically placed in relation to the earth's
orbit, it follows that its nearest distance from us in any particular
years may vary greatly. The nearest possible approach it can make in
regard to the earth is a little under 35,000,000 miles; when at the
opposite point of its orbit its nearest approach is about 62,000,000
miles from the earth. As the years of Mars and the earth differ greatly
in length, and the two planets move at different speeds, the very
favourable oppositions can only occur about once every forty-five years;
though a comparatively near opposition occurs about every fifteen years.
Such a close approach we have just witnessed, and it will be fifteen
years before Mars is again so near to the earth!
the relative positions of the two Planets, during the years 1909-10.
Mars passed over the dotted portion of its Orbit in the year 1910.
The Outer Circle is the Orbit of Mars, and the inner Circle is the
Orbit of the Earth. The Seasonal points on both Orbits show the Seasons
in the Northern hemisphere. In the Southern hemisphere the Seasons are
reversed, "Summer" occurring at the point marked "Winter," and "Spring"
at the point marked "Autumn," &c. &c.
The dotted downward line on the left-hand side shows the course taken
by the "Areonal", which left the Earth on the 3rd of August and
arrived at Mars on the 24th of September. * Shows the point reached
when John wished to turn back; and the lower dotted line, the
alternative course then suggested.
The long dotted line running upwards to the Spring Equinox of the Earth
shows the course taken on the homeward Voyage.
Drawn by M. Wicks.
Plate VII]
"The Martian year is equal to 687 of our days, but as the Martian days
are slightly longer than ours, this really represents 668 Martian days.
"The entire surface of Mars contains an area of about 56,000,000 square
miles, which is about one-fourth of the area of the earth's surface.
"Its gravity is only three-eighths of the earth's gravity, thus
everything upon Mars would weigh proportionately lighter than on the
earth, and the amount of labour required to do such work as digging or
lifting would be lessened. There would, for the same reason, be greater
ease of movement in walking, jumping, or running, and large bulky
animals like our elephants could move with almost the same ease and
freedom as our goats.
"Theoretically, we should expect to find the atmosphere upon Mars very
much thinner than our atmosphere, and actual observation proves this to
be the case. We are able to see details on the surface of Mars with very
much greater distinctness than would be the case if its atmosphere were
as dense as ours. Moreover, clouds are comparatively rarely seen; and
the majority that are observed present more the appearance of clouds of
sand than rain clouds. Usually, also, they float very much higher above
the planet's surface than our clouds are above the earth's surface; ten
miles high is quite an ordinary altitude, and some have been estimated
as quite thirty miles above the planet.
"Many theorists have attempted to prove that, owing to the planet's
distance from the sun, and the thinness of its atmosphere, the
temperature of Mars must be very low, probably below freezing-point even
at the equator. Dr. Alfred Russel Wallace has gone further than this,
and suggests that the temperature must be eighty degrees Centigrade
below freezing-point; that there is no water or water vapour on the
planet; and that it is quite impossible for life to exist there!
"However, as the result of delicate bolometric experiments, careful
calculations, and consideration of conditions affecting the result which
have not previously received so much attention, Professor Very has
arrived at a different opinion; and actual observation has shown that
there is very little indication of frost outside the frigid zones. Even
in the polar regions it is at times evidently warmer than at the earth's
poles, because during the spring and summer the snow-caps upon Mars not
only melt more rapidly, but melt to a much greater extent than our polar
caps do. In 1894 the southern polar snow-cap of Mars was observed almost
continuously during the melting period, and it was actually observed to
dwindle and dwindle until it had entirely disappeared. It is rather
strange to think that we know more about the snow-caps of that
far-distant world than we do about those on our own earth.
"Owing to the lesser gravity on Mars the snow and ice which forms the
caps would certainly be lighter and less closely compacted than the snow
and ice upon our earth; but it is quite clear that it could not melt to
any extent unless the temperature remained above freezing-point for a
considerable length of time.
"It has, however, seriously been contended that the Martian polar caps
are not snow at all, but frozen carbon dioxide-the poisonous dregs of
what once was an atmosphere. Carbon dioxide, however, melts and becomes
gaseous almost suddenly, but these polar snow-caps melt gradually,
exactly as frozen snow would; so this theory fails altogether to fit the
circumstances.
"Moreover, the water which accumulates all round the base of the melting
snow-cap has been carefully observed on many occasions, and in the early
stage of melting it appears blue in tint, but later on, as upper layers
of snow dissolve and those nearer the soil are reached, the water
presents a turbid and muddy appearance; exactly what might be expected
when water has been contaminated by the surface soil.
"Dr. Alfred Russel Wallace declines to accept the blue tint as any proof
that the liquid is water, and contends that shallow water would not
appear that colour when viewed from a distance. You will, however, have
observed that the water in all our shallow reservoirs appears intensely
blue when observed from any distant and elevated point of view. It seems
to me that when, as in the case of Mars, we have a very thin atmosphere
laden with sand particles, we have exactly the conditions which would
produce a very blue sky, and cause the water to appear a deep blue
colour when viewed from a distance.
"It is also contended that water cannot be present on Mars, because none
of our skilled spectroscopists has yet been able to demonstrate by the
spectroscope that there is any water vapour in the Martian atmosphere.
"This, however, is generally acknowledged to be a very difficult and
delicate operation; and, in any case, it is purely negative evidence,
and cannot be accepted as final. I feel quite confident that sooner or
later a means will be found of definitely proving the presence of water
vapour upon Mars by the aid of the usual lines in the spectrum. There
are too many evidences of its presence, such as clouds, hoarfrost, snow,
and seasonal changes in vegetation, to warrant the rejection of the idea
of its existence merely because it has not been detected by the
particular means hitherto used by the spectroscopists.
"Mr. Slipher, of Flagstaff Observatory, has made many experiments with
specially sensitised photographic plates. He has taken several
photographs of the spectrum of the moon and others of the spectrum of
the planet Mars. The plates of the lunar spectrum show a darkening of
the 'a' band, which indicates the presence of water vapour, and we know
that is due to the water vapour in our own atmosphere. The plates of the
spectrum of Mars show a much more definite darkening of the 'a' band,
and Professor Lowell contends that this can only be due to water vapour
in the atmosphere of Mars.
"Professor Campbell has, however, made similar experiments, and is of
opinion that Professor Lowell has been deceived by the water vapour in
our own atmosphere. Thus the matter stands at the present time, and we
must await the result of further investigation before we can consider
the matter settled.
"I, however, regard it as a certainty that improved means will
definitely show that water vapour undoubtedly exists in the Martian
atmosphere, and it is not unlikely that other constituents of that
atmosphere may also be identified, and possibly even the relative
quantities may be ascertained."
John here remarked that he had read of it being contended that life
could not exist on Mars because as water would boil at a temperature a
hundred degrees lower than it did on the earth, it would be impossible
to boil a potato properly, or make a good cup of tea. He thought,
however, that if water boiled at such a low temperature, then the
proportion of water vapour in the air would be increased, as evaporation
would be more rapid than on the earth.
"Undoubtedly so," I replied. "The first argument, however, is very weak.
For many thousands of years the people on the earth not only managed to
live, but attained a high state of civilisation, yet we have no reason
to believe that they ever ate potatoes or drank tea! Even in England we
have only known and used these articles for about three hundred years!
The inhabitants of any world would be suited to their environments.
"The polar-caps on Mars are shown on very early drawings of the planet;
but, up to the year 1877, little was known of the general surface
details beyond the fact that the general colour was orange-red,
diversified by dark patches of blue-green in some parts, and some
narrow, serpentine markings here and there. All these markings are now
much more accurately drawn, as the result of more careful and continuous
observation. Sir William Herschel suggested that the red colour was
attributable to the vegetation of Mars being red, instead of green as on
our earth; but it was generally considered that the red areas indicated
land and the dark areas water. The work of our modern observers has,
however, resulted in a general revision of our ideas on these points.
"It had long been reasoned that, as the earth was accompanied by a
moon, and Jupiter had at least four, Mars, the intermediate planet,
might be expected to possess a satellite. The planet itself being small,
its moon would probably be very small, and likely to be overlooked when
observing with the telescope, because its light would be overpowered by
the light of the planet, which would make the telescopic field of view
very bright. Up to the year 1877 the most powerful instruments had been
used without success in the search for the supposed satellite.
"In that year Mars made an exceptionally near approach to the earth, and
Professor Asaph Hall, of Washington Observatory, took up the search,
using a splendid refracting telescope having an object-glass 26 inches
in diameter. The methods he adopted were rewarded with success, for he
discovered not only one, but two satellites of Mars, and they were given
the names of Phobos and Deimos.
"Both these satellites are very close to the planet and extremely small,
Phobos being less than 4000 miles from the planet's surface, and Deimos
only 12,300 miles from it. As seen in the telescope, they are very faint
points of light which cannot be measured by ordinary means, and the
estimation of their size was a matter of great difficulty.
"Professor Langley gives an interesting account of the endeavour to
estimate their size by the amount of light reflected, as compared with
the light afforded by our own moon when full. It was a most difficult
task, as the comparison had to be made by means of tiny holes drilled in
metal plates; and for a long time it was impossible to find a workman
who could drill a hole sufficiently small for the purpose, although one
of those employed had succeeded in drilling a hole through a lady's thin
cambric needle from end to end, thus converting it into a tiny steel
tube. One would have thought such a feat impossible; yet what was now
required was a hole smaller than the one thus made through the tiny
needle."
"My word!" said M'Allister, "I would like to see the mon who did that
piece of work, and shake hands with him; he must be a rare clever
fellow!"
"Yes," said John, "and I would like to see the drill he used; for such a
long and extremely slender tool, to be effective, must be as clever a
piece of work as the steel tube."
"I may tell you," I proceeded, "that success was at last attained; and
as a result of the comparison of our moon's light with that of Deimos,
it was shown that if the general surface brightness of the latter were
equal to that of our moon, then Deimos must be only 18 miles in
diameter, or about a 15,000th part of the area of our moon's disc.
"To state the matter in another way-supposing our moon were only 18
miles in diameter, and was removed to the same distance as Deimos is
from us, then it would appear only the very faint point of light that
Deimos appears when viewed through the telescope.
"By the same means Phobos, the satellite nearest to Mars, was estimated
to be about 22-1/2 miles in diameter. These dimensions, however, depend
on the brightness of these satellites being exactly the same as the
general brightness of our moon; and later experiments have fixed the
sizes as 36 miles for Phobos, and 10 miles as the diameter of Deimos.
"I will not detain you much longer on this subject, as we shall be able
to discuss it further when we arrive upon Mars; but I may now mention
that, in one respect, the little satellite named Phobos is unique. It is
the only satellite we know of which revolves round its primary planet in
less time than it takes the planet itself to make one revolution on its
axis.[6]
"Mars revolves on its axis in 24 hours, 37 minutes, and 22 seconds, thus
the 'day' on Mars is nearly 38 minutes longer than our 'day.' Phobos
revolves round the planet in the very short period of 7 hours, 39
minutes, and 14 seconds, and therefore makes more than three complete
revolutions round the planet in the course of a single Martian day. The
peculiar phenomena to which this very rapid motion gives rise, and the
numerous eclipses which occur, will be matters of great interest to us
all when we reach Mars. Our moon, as you know, takes a month to make one
revolution round the earth."
"Professor," said John, "when we get to Mars, it will be rather a
curious experience for us to see two moons shining in the sky at the
same time!"
"My word!" exclaimed M'Allister, "two moons shining at once! If I go out
and see such a sight as that, I shall think the whisky has been a wee
bit too strong for me!"
"Well," replied John, "if your usual drink has the effect of making you
see double, take good advice, and leave the whisky severely alone when
you are on Mars, or else you will be seeing four moons all at once,
and receive such a shock that you will never get over it!"
M'Allister laughed pleasantly as John said this. He is a real good
fellow, and takes all John's chaff with the utmost good-humour; but, in
justice to him, I must say that, although he sticks to his national
drink like a true Scot, I have never once seen him any the worse for it.
He knows his limitations, and always keeps within them.