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Excellent or better condition.

Prepared with the co-operation of

Science Service

MOOM

PUBLISHED BY NELSON DOUBLEDAY, INC. AND ODHAMS BOOKS LTD.

PRINTED IN THE UNITED STATES OF AMERICA

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MOON

Science Program

MOON

Prepared with cooperation of

Science Service

Washington D. C.

PUBLISHED BY NELSON DOUBLEDAY, INC.

GARDEN CITY, NY

MOON

Label

for

Album Case

MOISTEN AND APPLY THESE SPECIALLY GUMMED STAMPS

SCIENCE PROGRAM

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Lacne

A New Look at an Old Neighbor

HEN MAN REACHED OUT and touched the moon for the first time on

20 July, 1969-with the landing of two American astronauts in a

spacecraft called Eagle-a dream of many centuries was fulfilled.

Since antiquity, earth's only natural satellite has been an object of

awe, veneration and curiosity. The moon has been a source of mystery,

an inspiration for legends, songs and poems. From earliest days, it has

been man's aim to "conquer" his old neighbor.

Now we are well on the way.

Although the moon is not large as celestial bodies go-with a diameter

only one-quarter that of earth-it is nevertheless fairly impressive in

appearance. It is bright-only the sun appears more brilliant-and near

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CHO

The most obvious feature on

the moon, and most easily seen

with the naked eye, is the crater

Tycho and its huge ray system,

shown in detail below.

The world's biggest telescope, the

200-inch Hale telescope at Mt.

Palomar, is shown here pointing

to the zenith, straight up.

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In Brief: Useful Facts About the Moon

Distance The moon is our nearest neighbor in space, revolving round

the earth at a mean distance of 238,857 miles or less than ten

times the distance round the earth's equator.

Dimensions The moon has a diameter of 2,160 miles, roughly one-

quarter that of the earth. The density of the moon is 0.606 that of the

earth.

Surface Gravity One-sixth that of earth.

Mass One-hundredth that of earth.

Orbit The moon's orbit has an eccentricity of 0.055, the perigee and

apogee distances being 221,593 and 252,948 miles. The interval

between successive new moons is 29 days 12 hours 44 minutes.

Rotation Tidal friction has resulted in the rotation of the moon being

captured, or made equal to the period of rotation round the earth.

As a result, the same hemisphere of the moon is always presented

to viewers on earth.

Maria The seas, or maria, can be seen with the naked eye. There is no

water observable on the moon, but in the past there probably were

seas of lava. The largest is the Ocean of Storms, with an area

almost twice that of the Mediterranean. The Sea of Showers covers

more area than Britain and France combined.

Mountains The highest chains are the Leibnitz and Dorfel, in the far

south. They exceed 30,000 feet, and thus are higher than Mount

Everest.

Craters In size, the craters range from vast formations such as Bailly-

with a diameter of more than 160 miles-down to tiny pits at the

very limit of visibility. They are found everywhere. The depths

are great-29,000 feet in the case of Newton-but in relation to

their diameters the craters are shallow. Clavius is 17,000 feet deep

and 145 miles in diameter, so it is more like a saucer than a well.

Atmosphere The moon possibly may possess an infinitesimally thin at-

mosphere made up of argon and other chemically inert gases, re-

leased by the decay of radioactive potassium.

Temperature From almost 250 degrees above zero F. during the lunar

day, to 250 degrees below zero F. at the lunar midnight.

Life Animals are out of the question. It is not impossible that very

primitive plant forms may survive in a few places--but even that is

unlikely. It is reasonable to assume that the moon is without life.