1. UNIT 2 THE SOLAR SYSTEM Vocabulary Review

2. IN THE ORBIT OF A PLANET OR ANOTHER BODY IN THE SOLAR SYSTEM, THE POINT THAT IS FARTHEST FROM THE SUN aphelion

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

4. THE PATH THAT A BODY FOLLOWS AS IT TRAVELS AROUND ANOTHER BODY IN SPACE orbit

5. IN THE ORBIT OF A PLANET OR ANOTHER BODY IN THE SOLAR SYSTEM, THE POINT THAT IS CLOSEST TO THE SUN perihelion

6. A ROTATING CLOUD OF GAS AND DUST FROM WHICH THE SUN AND PLANETS FORMED solar nebula

7. THE INWARD FORCE REQUIRED TO KEEP A PARTICLE OR AN OBJECT MOVING IN A CIRCULAR PATH centripetal force

8. A SMALL BODY FROM WHICH A PLANET ORIGINATED IN THE EARLY STAGES OF THE SOLAR SYSTEM planetesimal

9. THE PROCESS BY WHICH THE NUCLEI OF SMALL ATOMS COMBINE TO FORM A NEW, MORE MASSIVE NUCLEUS; THE PROCESS RELEASES ENERGY nuclear fusion

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

11. A DARK AREA OF THE PHOTOSPHERE OF THE SUN THAT IS COOLER THAN THE SURROUNDING AREAS AND THAT HAS A STRONG MAGNETIC FIELD sunspot

12. AN EXPLOSIVE RELEASE OF ENERGY THAT COMES FROM THE SUN AND THAT IS ASSOCIATED WITH MAGNETIC DISTURBANCES ON THE SUN’S SURFACE solar flare

13. A UNIT OF MEASURE EQUAL TO THE AVERAGE DISTANCE BETWEEN THE EARTH AND THE SUN; APPROXIMATELY 150 MILLION KM astronomical unit

14. A PLANET THAT HAS A DEEP, MASSIVE ATMOSPHERE, SUCH AS JUPITER, SATURN, URANUS, AND NEPTUNE gas giant

15. ONE OF THE HIGHLY DENSE PLANETS NEAREST TO THE SUN terrestrial planet

16. 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

17. 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

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

19. 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

20. A SMALL, ROCKY OBJECT THAT ORBITS THE SUN; MOST ARE LOCATED IN A BAND BETWEEN THE ORBITS OF MARS AND JUPITER asteroid

21. A METEOROID THAT REACHES EARTH’S SURFACE WITHOUT BURNING UP COMPLETELY meteorite

22. 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

23. 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

24. A RELATIVELY SMALL, ROCKY BODY THAT TRAVELS THROUGH SPACE meteoroid

25. A BRIGHT STREAK THAT RESULTS WHEN A METEOROID BURNS UP IN EARTH’S ATMOSPHERE meteor

26. Well done!