MERCURY - faster than the fastest rocket, the planet Mercury flashes through the inner solar system

Sep 29, 2026

Mercury—presented as the planet closest to the sun—is introduced through kid-friendly explanations of its location, speed, orbit, and visibility from Earth. The text describes the inner solar system as the space between Earth and the sun and explains why Mercury is fast, why it has no moons, and how gravity affects orbital motion. It also covers viewing conditions near sunrise or sunset and why Mercury appears dim.

LanguageEnglish

CategoryLiterature

FormatPDF

Pages36

Reading Time55 min

AccessFree to download

Mercury

Overview of the inner solar system

How fast Mercury moves and why

Mercury’s orbit and year length

Ancient views and observing Mercury from Earth

# Boston Public Library 9 # G R E G ○ R Y L. VO G T MERCURY Gateway Solar SystemThe Millbrook PressBrookfield,Connecticut Published by The Millbrook Press2 Old New Milford RoadBrookfield,Connecticut 06804 Copyright ◎1994 by The Millbrook PressAll rights reservedPrinted in the United States of America 5432 Library of Congress Cataloging-in-Publication DataVogt,Gregory.Mercury /by Gregory L.Vogt.p.cm.—(Gateway solar system)Includes bibliographical references and index. Summary:Presents information on Mercury,the planet closestto the sun,as it was photographed by the U.S.spacecraft,Mariner 10.Includes a glossary and "Mercury Quick Facts." ISBN 1-56294-390-1(lib.bdg.)ISBN 0-7613-0157-7(pbk.) 1.Mercury (Planet)—Juvenile literature.2.Project Maniner—Juvenile literature.[1.Mercury(Planet).2.Project Mariner.] 1.Title.II.Series:Vogt,Gregory.Gateway solar system. QB611.V641994 93-11218 CIP AC 523.4'1—dc20 Photographs and illustrations courtesy of:National Aeronautics and Space Administration:cover,pp.8,10,11,19,22,26; painting by Willam K.Hartmann:p.4;◎ Ron Miller:pp.12, 15,24:Jet Propulsion Laboratory:pp.17.21. Solar system diagram by Anne Canevari Green MERCURY aster than the fastest rocket,the planet Mercury flashesthrough the inner solar system.The inner solar systemis the space between Earth and the sun.It is a lonelyregion with only two planets,Mercury and Venus.Thereare no moons,and only an occasional comet or asteroidpassing through. At an average distance of 36 million miles (58 mil-lion kilometers),Mercury is the closest planet to the sun.Because it is so close,it is also the fastest moving of theplanets.Mercury whizzes around the sun at an averagespeed of over 107,000 miles(173,000 kilometers)perhour.That's about ten times faster than distant Plutomoves as it travels in its orbit around the sun.Mercuryis faster than any other planet because the sun's gravity(a force that causes objects to attract each other)isstronger the closer you are to it.To stay in orbit and notfall into the sun,Mercury has to move very fast.Its speedbalances the sun's gravity. / Because of its closeness to the sun,Mercury has asmaller orbit to travel than any other planet.With itsspeed and small orbit,Mercury travels completely aroundthe sun every 88 Earth days. Ancient Planet Mercury is a difficult planet to see from Earth.It is soclose to the sun that the sun's light usually obscures it.The only times to view Mercury are just before sunriseor just after sunset,when the sun is below Earth's hori-zon and its glare is blocked.Mercury has a dark surface,so only about one tenth of the sunlight that falls on it isbounced back into space.That means that,comparedwith other planets,such as Venus,·Mercury is very dim.Its dimness,combined with the sun's twilight glare anda hazy Earth atmosphere,makes Mercury a real chal-lenge to spot.In ancient times,however,the air was notas polluted as it is now and Mercury was much easier tosee.Mercury was known to many people,including theEgyptians,Greeks,and Babylonians. After the invention of the telescope in the early1600s,many astronomers,scientists who study objectsin space,attempted to get a closer look at Mercury'ssurface.But even with large modern telescopes,details PlutoNeptuneUranusSaturnJupiterMarsEarth—Venus-Mercury-SUN Earth Viewed from Earth,Mercury is never more than 28 degrees to the side ofthe sun. on its surface are hard to see.If Mercury had a moun-tain,for example,it would have to be at least 435 miles(700 kilometers)across just to appear as a tiny dotthrough the biggest telescopes.Therefore,hand-drawnmaps and telescopic photographs revealed only shad-owy features. Nevertheless,astronomers formed many theoriesabout what the planet must be like.Some astronomers

FAQs

Why is Mercury the fastest-moving planet?

Mercury moves fastest because the sun’s gravity is stronger when you are closer to the sun. Its speed balances that stronger pull so it stays in orbit.

How long does it take Mercury to orbit the sun?

Mercury travels completely around the sun every 88 Earth days.

When can Mercury be seen from Earth?

Mercury is easiest to view just before sunrise or just after sunset, when the sun is below Earth’s horizon and its glare is blocked.

Sep 29, 2026

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