Handout 27-3 The Inner Planets

1 The planets closest to the sun are called the ____________________. inner planets

2 Name the four inner planets Mercury Venus Earth Mars

3 The inner planets are also called ______________________ because they are like Earth. terrestrial planets

4 Describe the composition of the inner planets. Made mostly of solid rock with metallic cores.

5 Bowl-shaped depressions called _______________________ formed on the surfaces of inner planets when the planets collided with other objects in space. impacts craters

Mercury

6 Mercury, the closest planet to the sun, circles the sun every B: 88 days

7 Mercury rotates on its axis once every C: 59 days

8 Mercury’s surface features a long line of cliffs and B: a large number of craters

9 The absence of a dense atmosphere and Mercury’s slow rotation contribute to D: a large daily temperature range

VENUS Phases of Venus seen from Earth

10 How long is the orbital period of Venus, the second planet from the sun? 225 days

11 How often does Venus rotate? Once every 243 days

12 The planet that Venus most resembles in mass, size, and density is ________________________. Earth

13 Venus’s atmospheric pressure is about ___________ times the pressure on Earth. 90

14 What two factors cause the high temperatures on Venus? It is close to the sun High amount of carbon dioxide in its atmosphere

15 What percentage of the atmosphere on Venus is composed of carbon dioxide? 96%

16 Venus appears to be very bright in the night sky because drops of _________________________ form a cloud layer that reflects sunlight. Sulfur dioxide

17 Why is Venus commonly referred to as the evening star or morning star? It is usually visible from Earth only in the morning or early evening.

18 The surface of Venus is composed of which two types of rock? Basalt and granite

19 19. Magellan B: a U.S. satellite that collected data about Venus

20 volcano C. a landform commonly found on Venus

21 Maat Mons A. the highest volcano on Venus

Earth

22 Earth is the ________________ planet from the sun. third (rock from the sun)

23 The orbital period of Earth is ______________ days. 365 1/4

24 Earth completes one __________________ on its axis every day. rotation

25 How many moons does Earth have? one

26 Over the last ______________ years, Earth’s continents separated from a single landmass and drifted to their present. 250 million

27 What two factors have caused the surface of Earth to keep changing? Weathering and erosion

28 Why is Earth the only planet on which water exists in a liquid state? Earth’s unique atmosphere Distance from sun allows water to exist in the liquid state

29 How was Earth able to maintain the moderate temperatures that were necessary to support life? The oceans and atmosphere help Earth to have moderate temperatures.

30 What three elements does Earth have in the proper combination necessary to support life? Water, oxygen, and temperature

Mars

31 Mars is the ____________________ planet from the sun. fourth

32 How long is Mars’s orbital period? 687 days

33 How often does Mars rotate on its axis? Every 24 hours and 37 minutes

34 Why are Mars’s seasons similar to Earth’s? Its axis tilts at nearly the same angle as Earth’s.

35 Mars is believed to have been geologically active because of its massive volcanoes and a system of deep ________________ on its surface. canyons

36 One of the many major volcanic regions on Mars is called ___________________. Tharis Montes

37 The largest volcano on Mars is ___________________________, which is three times the height of Mount Everest. Olympus Mons

38 Why do scientists think that Martian volcanoes have grown so large? Mars does not have tectonic plates

39 Two seismic wave-producing geological events called _______________________ indicate that volcanoes on Mars may still be active. mars quakes

The End