UNIT 2

THE SOLAR SYSTEM

Vocabulary Review

THE FORCE OF ATTRACTION BETWEEN OBJECTS THAT IS DUE TO THEIR MASSES

gravity

THE PATH THAT A BODY FOLLOWS AS IT TRAVELS AROUND ANOTHER

BODY IN SPACE

orbit

IN THE ORBIT OF A PLANET OR ANOTHER BODY IN THE SOLAR SYSTEM, THE POINT

THAT IS CLOSEST TO THE SUN

perihelion

IN THE ORBIT OF A PLANET OR ANOTHER BODY IN THE SOLAR SYSTEM, THE POINT

THAT IS FARTHEST FROM THE SUN

aphelion

THE INWARD FORCE REQUIRED TO KEEP A PARTICLE OR AN OBJECT MOVING IN A

CIRCULAR PATH

centripetal force

A ROTATING CLOUD OF GAS AND DUST FROM WHICH THE SUN AND PLANETS

FORMED

solar nebula

A SMALL BODY FROM WHICH A PLANET ORIGINATED IN THE EARLY STAGES OF THE

SOLAR SYSTEM

planetesimal

THE PROCESS BY WHICH THE NUCLEI OF SMALL ATOMS COMBINE TO FORM A NEW, MORE MASSIVE

NUCLEUS; THE PROCESS RELEASES ENERGY

nuclear fusion

A DARK AREA OF THE PHOTOSPHERE OF THE SUN THAT IS COOLER THAN THE SURROUNDING AREAS

AND THAT HAS A STRONG MAGNETIC FIELD

sunspot

A LOOP OF RELATIVELY COOL INCANDESCENT GAS THAT EXTENDS ABOVE THE PHOTOSPHERE AND ABOVE THE SUN’S EDGE AS SEEN FROM EARTH

prominence

AN EXPLOSIVE RELEASE OF ENERGY THAT COMES FROM THE SUN AND THAT IS ASSOCIATED WITH

MAGNETIC DISTURBANCES ON THE SUN’S SURFACE

solar flare

ONE OF THE HIGHLY DENSE PLANETS NEAREST TO THE SUN

terrestrial planet

A UNIT OF MEASURE EQUAL TO THE AVERAGE DISTANCE BETWEEN THE EARTH

AND THE SUN; APPROXIMATELY 150 MILLION KM

astronomical unit

A PLANET THAT HAS A DEEP, MASSIVE ATMOSPHERE, SUCH AS JUPITER, SATURN,

URANUS, AND NEPTUNE

gas giant

A DISK OF MATTER THAT ENCIRCLES A PLANET AND THAT CONSISTS OF NUMEROUS PARTICLES IN ORBIT,

WHICH RANGE IN SIZE FROM DUST GRAINS TO OBJECTS TENS OF METERS ACROSS

planetary ring

A CELESTIAL BODY THAT ORBITS THE SUN, IS ROUND BECAUSE OF ITS OWN GRAVITY, BUT HAS NOT CLEARED ITS ORBITAL PATH

dwarf planet

A REGION OF THE SOLAR SYSTEM THAT STARTS JUST BEYOND THE ORBIT OF NEPTUNE AND THAT

CONTAINS DWARF PLANETS AND OTHER SMALL BODIES MADE MOSTLY OF ICE

Kuiper Belt

ONE OF THE HUNDREDS OR THOUSANDS OF SMALL BODIES THAT ORBIT THE SUN IN A FLAT BELT BEYOND NEPTUNE’S ORBIT; ALSO INCLUDES DWARF PLANETS

LOCATED THERE

Kuiper Belt object

A SMALL BODY THAT GIVES OFF GAS AND DUST AS IT PASSES CLOSE TO THE SUN; IT MOVES IN AN

ELLIPTICAL ORBIT AROUND THE SUN AND IS MADE OF DUST AND FROZEN GASES

comet

A SPHERICAL REGION THAT SURROUNDS THE SOLAR SYSTEM THAT EXTENDS FROM THE KUIPER BELT TO

ALMOST HALFWAY TO THE NEAREST STAR, AND THAT CONTAINS BILLIONS OF COMETS

Oort cloud

A SMALL, ROCKY OBJECT THAT ORBITS THE SUN; MOST ARE LOCATED IN A BAND

BETWEEN THE ORBITS OF MARS AND JUPITER

asteroid

A RELATIVELY SMALL, ROCKY BODY THAT TRAVELS THROUGH SPACE

meteoroid

A BRIGHT STREAK THAT RESULTS WHEN A METEOROID BURNS UP IN EARTH’S

ATMOSPHERE

meteor

A METEOROID THAT REACHES EARTH’S SURFACE WITHOUT BURNING UP

COMPLETELY

meteorite

Well done!