Chapter 6

Question 1

what does the solar system look like?

Answer 1

• some planets have unusual tilts, large moons, or moons with unusual orbits
• some planets are rocky and some are large hydrogen rich jovian planets
• swarms of asteroids and comets populate the solar system (steroids between mars and Jupiter, oort cloud (even more comets))

Question 2

planets are are very tiny compared to what?

Answer 2

distances between them

Question 3

Describe the Sun..

Answer 3

• over 99.8% of solar system’s mass
• 100 times bigger than the sun
• made mostly of Hydrogen and Helium gas (plasma)

Question 4

Describe Mercury…

Answer 4

• made of metal and rock: large iron core
• desolate, cratered; long, tall, steep cliffs, no moon
• very hot and very cold: 425C during day and 170C at night
• closest to the sun

Question 5

Describe Venus…

Answer 5

• is it the hottest bc of thick atmosphere
• nearly identical size to earth
• no moon
• extreme green house effect

Question 6

Describe Jupiter

Answer 6

• father from sun than inner planets
• No solid surface (mostly H/He) like sun
• 300 times more massive than earth
• many moons and rings
• jupiter has 4 galilean moons

Question 7

Four Galilean moons

Answer 7

• Io ; active volcanoes all over
• Europa; possible subsurface ocean
• Ganymede; Largest moon in solar system
• Callisto- a large cratered “ice ball’

Question 8

Jovian ring systems

Answer 8

• all four jovian planets
• others have ring particles that are smaller and darker than saturn’s
• jovian ring system just means they have moons

Question 9

Icy bodies are

Answer 9

many icy bodies like pluto, beyond neptune (kuiper belt objects)
-largest ones are compared to the earths moons (eris is bigger than pluto)

Question 10

pluto and other dwarf planets

Answer 10

• icy comet like composition

- much smaller than other planets

Question 11

major planet types

Answer 11

• terrestrial planets are rocky, relatively small and close to the sun
• jovian planets are gaseous, larger, and farther from the sun

Question 12

why are there two major types of planets?

Answer 12

-most mass is h/he 98%

Question 13

inside of the frost line

Answer 13

too hot for hydrogen compounds to form ice

• hydrogen compounds stay gaseous
• metals and rocks condense

Question 14

outside of the frost line

Answer 14

cold enough for ice to condensate

Question 15

Formation of terrestrial planets

Answer 15

• small particles of rocks and metal were present inside the frost line
• planetesimals of rocks and metal built up as these particles are collided
• they collide and they make planets

Question 16

gravity draws planetesimals together to form

Answer 16

planets

Question 17

this process of assembly is called

Answer 17

accretion

Question 18

formation of jovian planets

Answer 18

• ice could also form small particles outside the frost line
• larger planetisimals and planets were able to form
• the gravity of these larger planets was able to draw in surrounding H and He gases.

Question 19

where did steroids and comets come from?

Answer 19

• left over from the accretion process
• rocky steroids inside frost line
• icy comets outside frost line

Question 20

solar system is how old?

Answer 20

4.5 billion years (age dating meteorites that are unchanged)

Question 21

when did planetesimals bombarded other objects?

Answer 21

late stages of solar system formation

Question 22

the origin of earths water

Answer 22

icy planetesimals from the outer solar system

Question 23

how do we explain the existence of our moon and other exceptions to the rules?

Answer 23

• captured them (planetesimals)

- giant impact

Question 24

Gravitational Tugs

Answer 24

• suns motion depends on the planets tugs
• astronomers who measured this motion around the stars could determine masses and orbits of all planets
• (gravitational change bc planets are changing position)

Question 25

Astronomic Technique

Answer 25

• detecting planets by measuring the change in a star’s position in the sky
• however these tiny motions are difficult to measure

Question 26

Doppler Technique

Answer 26

• measuring a star’s doppler shift can tell us its motion towards and away from us
• current techniques could measure motions as small as 1 m/s

Question 27

first extrasolar planet detected

Answer 27

• short period means small orbital distance
• first planet was discovered in 1995
• monitors 1 star
• moving away from us every 4 days

Question 28

the bigger the planet

Answer 28

the easier it is to see its light

Question 29

a transit is when

Answer 29

a planet crosses in front of a star (edge on)

Question 30

the resulting eclipse

Answer 30

reduces the stars apparent brightness and tells us the planets radius

Question 31

what can be obtained when there is no orbital tilt?

Answer 31

accurate measurement of planet mass can me obtained

Question 32

Hot Jupiters

Answer 32

• close to star

- 5 AU from sun