CHAPTER VIII_Great Inventions and Discoveries

ASTRONOMICAL DISCOVERIES AND INVENTIONS

"When I consider thy heavens, the work of thy fingers, the moon and the

stars, which thou hast ordained, what is man, that thou art mindful of

him?" The Hebrew psalmist feels the insignificance of man compared with

the infinitude of the heavens. Victor Hugo expresses the opposite

thought: "There is one spectacle grander than the sea--that is the sky;

there is one spectacle grander than the sky--that is the interior of

the soul."

There is nothing more dignified, more sublime, more awful, than a

contemplation of the heavens. In point of grandeur, astronomy may be

regarded as king of the sciences. It is also their patriarch. Thousands

of years before the birth of Christ the priests of Chaldea, from the

tops of their flat-roofed temples, studied the stars and laid the

foundations of the science of astronomy. The heavens, with their

teeming, whirling, circling congregation, obeying laws that have no

"variableness neither shadow of turning" do, indeed, "declare the glory

of God."

From the earliest times the stars were supposed to influence for good

and ill the lives of men. There were supposed to be stars of good luck

and of bad omen. The cool, calculating Cassius tells Brutus,

"The fault, dear Brutus, is not in our stars,

But in ourselves, that we are underlings."

When you look up into the heavens at the flickering dots of light

which we call the stars, you are looking at worlds, many of them far

larger than our earth. They seem small because of vast distances from

us. Our own solar system, great as it is, in comparison with the

celestial universe is but a clod in an acre. At the center of our

system is the sun, a huge ball of fiery matter 93,000,000 miles from

the earth, and as large as 330,000 worlds like ours. Circling around

the sun like maddened horses around a race course are eight planets.

These planets, with the sun and some comets, constitute our solar

system; _our_ system, for how many solar systems there are in space no

one knows. These planets, in their order outward from the sun, are

Mercury, Venus, our Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Of these, Mercury is the smallest and Jupiter is the largest. The

following table shows some interesting facts about the planets:

--------+----------+------------+-------------+-------------+----------

--------+----------+------------+-------------+-------------+----------

Mercury | 3,008 | 5,000,000 | 36 | 88 | 107,012

Venus | 7,480 | 425,000 | 66 | 225 | 78,284

Earth | 7,926 | 332,260 | 92 | 365-1/4 | 66,579

Mars | 4,999 | 3,093,500 | 141 | 687 | 53,938

Jupiter | 88,439 | 1,048 | 483 | 4,332 | 29,203

Saturn | 75,036 | 3,502 | 886 | 10,759 | 21,560

Uranus | 30,875 | 22,600 | 1,783 | 30,687 | 15,202

Neptune | 37,205 | 19,400 | 2,794 | 60,127 | 12,156

--------+----------+------------+-------------+-------------+----------

The moon is 240,000 miles from the earth, and it would require nearly

24,500,000 moons to equal the sun in size. Other planets have moons,

some of them several. If you lived on the planet Mercury, your annual

birthday would come around about once in three of our months. If you

had your home out on the border land of the solar system, on the planet

Neptune, you would have a birthday once in about 165 years, as we count

time on the earth. It will be observed that the closer the planet is to

the sun, the faster it travels in its orbit. This fact is due to the

power of gravitation toward the sun. This strange influence drives the

planets around the sun, and the nearer the planet is to the sun the

greater is the power and consequently the faster the revolution. The

law of gravitation was discovered by Sir Isaac Newton.

Newton was born in 1642 in Lincolnshire, England. His father was a

farmer, and the farmhouse in which the son was born is still preserved.

He was educated at a grammar school in Lincolnshire, and later entered

Trinity College, Cambridge, from which he was graduated in 1665. Early

in life he displayed a great liking for mathematics. Within a few years

after he entered college, he had mastered the leading mathematical

works of the day and had begun to make some progress in original

mathematical investigation.

Newton's great life work--the achievement which insured to his name a

place among the immortals--was suggested to him by accident. As the

story goes, while he was walking one day in a garden, he saw an apple

fall from a tree. He speculated upon the reasons for its falling, and

ultimately concluded that the same force which causes an apple to fall

from a tree holds the heavenly bodies in their places. Further

investigation brought him to the unfolding of this general law of

gravitation: "Every body in nature attracts every other body with a

force directly as its mass, and inversely as the square of its

distance." This law is the greatest law of nature. It is the central

fact of the physical universe, the cement of the material world, the

mighty, mystic shepherdess of space, that keeps the planets from

wandering off alone. It is this awful, silent power reaching out from

the enormous mass of the sun, that lashes the planets in their furious

race, and yet holds them tightly reined in their orbits.

Newton was one of the greatest mathematicians, scientists, and thinkers

in the history of the world. He died at Kensington, England, on March

20, 1727, and was buried in Westminster Abbey, with the illustrious

dead of Great Britain.

[Illustration: SIR ISAAC NEWTON]

The operation of this law of gravitation pointed the way to the

discovery of the planet Neptune, which is considered the greatest

triumph of mathematical astronomy since the days of Newton. Prior to

the discovery of Neptune, Uranus was the outermost known planet of the

solar system. It was noticed that Uranus was being pulled out of its

proper path. It was being tugged away by some strange force beyond the

edge of the known planetary system. As the result of a skilful and

laborious investigation, Leverrier, a young French astronomer, wrote in

substance to an assistant in the observatory at Berlin: "Direct your

telescope to a point on the ecliptic in the constellation of Aquarius

in longitude 326 deg., and you will find within a degree of that place

a new planet, looking like a star of the ninth magnitude, and having a

perceptible disk." Leverrier did not know of the existence of such a

planet. He calculated its existence, location, and mass from the fact

that some such body must be there, to account for the disturbance

caused to Uranus. The telescope in the Berlin Observatory was directed

to the place designated by Leverrier, and on the night of September 23,

1846, in exact accordance with his prediction and within half an hour

after the astronomers had begun looking, Neptune was discovered within

less than one degree from the exact spot where Leverrier had calculated

it must be. Such are the triumphs of the human mind. Such are the

failures of nature to hide her secrets from the inquiry of man, even

behind untold millions of miles.

According to the principles of gravitation as unfolded by Newton, the

power of attraction decreases directly as the square of the distance

between the sun and a planet. Neptune, being on the outer rim of the

system and hence farthest away from the sun, moves in its orbit around

the sun more sluggishly than any other planet. Life such as we know it

on the earth could not exist on Neptune; it would be too cold. The

light and heat from the sun on Neptune are only one nine hundredth part

of what we get on the earth. But even so, the sunlight falling upon

Neptune is equal in power to seven hundred of our full moons. It was

thought that Uranus was the last planet of the solar system until

Neptune was found. Whether Neptune is the last, or whether other worlds

are roaming around beyond it, is not known.

Ptolemy, who was one of the most celebrated astronomers of earlier

times, was born in Egypt about a century and a half after Christ.

According to the Ptolemaic system of astronomy, which Ptolemy expounded

but did not originate, the earth was considered the center of the

universe, and around it the other planets and the sun were believed to

revolve. A passage in the Bible in which Joshua commanded the sun to

stand still indicates that the old Hebrews believed the sun circled

around the earth. The Ptolemaic theory did not account for all the

facts observed by astronomers, but for nearly fifteen centuries it held

practically universal sway over the belief of men, until another

thinker set the matter right.

Nicholas Copernicus was born in Prussia, February 19, 1473. He studied

mathematics, medicine, theology, and painting, but his greatest

achievements were in astronomy. He made holes in the walls of his room,

through which he might observe the stars. Copernicus did not believe in

the theory of Ptolemy that the earth was the center of the universe,

but held that the solar system had for its center the sun, and that

around it the planets, including the earth, revolved. In working out

this belief, which science has subsequently shown to be correct, he

laid the foundations of the modern system of astronomy.

The book in which Copernicus expounded his theory was begun in 1507 and

was completed in 1530. He could not be induced to publish it, however,

until shortly before his death. On May 24, 1543, he lay dying in

Frauenburg. A few hours before his death, when reason, memory, and life

were slipping away from him, the first printed copy of his book was

borne to Frauenburg and placed in the great astronomer's hands. He

touched the book, looked at it for a time, and seemed conscious of what

it was. Quickly afterward he lapsed into insensibility and was gone.

Johann Kepler, who was born in Germany in 1571, contributed several

important facts to astronomy. He studied the motions and laws of the

celestial bodies. Copernicus taught that the planets revolved around

the sun in circular orbits, but Kepler discovered that their paths are

ellipses. He also found that the nearer the planets are to the sun the

faster they travel. Kepler's discoveries were embodied in three great

laws of astronomy known as Kepler's laws. These furnished the

foundation for Newton's discoveries and are the basis of modern

astronomy. Kepler died in November, 1630.

Many of the wonderful discoveries that have been made in the field of

astronomy could not have been possible without the telescope, the most

important instrument used by astronomers. The first part of the word

is the same Greek adverb meaning "afar," found in _telegraph_ and

_telephone_; the last part is derived from a Greek verb meaning "to

see." The telescope, therefore, is an instrument for seeing objects

that are far off. It is a long tube With lenses so arranged as to make

objects appear much larger than they would to the naked eye. The

telescope was invented by a Dutch optician named Hans Lippershey about

three hundred years ago. The Italian scientist Galileo, who was born

at Pisa in February, 1564, heard of the invention, began studying the

principles upon which it depends, and greatly improved it. Galileo was

the first to use the telescope for astronomical purposes. With it he

discovered the satellites of Jupiter, the spots on the sun, and the

hills and valleys of the moon.

[Illustration: GALILEO]

At the present time the largest telescopes in the world are made and

owned in America. The largest is the Yerkes telescope, belonging to the

University of Chicago and located on the shores of Lake Geneva,

Wisconsin. Microscopes, opera glasses, and other magnifying instruments

depend upon the same principles as the telescope.

One of the most astounding of man's tools is the spectroscope, an

instrument used for analyzing light. Through a knowledge of chemistry

scientists can establish scientific relations between different

substances and the light which they emit. By analyzing the light from

the heavenly bodies with the aid of the spectroscope, and comparing

this result with the light sent out from different known kinds of

matter, man can stand on this little flying speck of matter we call the

earth and discover of what substances the stars are made.

One of the most interesting questions arising in a study of the

heavenly bodies is whether or not any of them besides the earth are

inhabited. Is there any good reason for supposing that our pigmy

planet, so insignificant compared with many celestial bodies, is the

only one containing life? On the other hand, life such as we know it

could not exist on some of the other planets. Mercury would be too hot;

Neptune too cold. Climatic conditions on Mars are most nearly like

those of the earth. Within recent years the telescope has revealed on

the surface of Mars a number of peculiar, regular lines. Many

scientists hold that these are artificial canals or irrigation ditches,

and that the planet must be inhabited. The theory does not seem at all

unreasonable. But the most that can be safely said is that if any of

the other planets are inhabited, the most likely one is Mars.