Lecture 5 - Our Planetary System Flashcards
describe the composition of planets closer to sun and further from sun
closer to sun = more round and rocky
further from sun = more gaseous
how many major planets are there? what is the shape of their orbits?
8 major planets, nearly circular orbits
what are the 2 differences btwn Dwarf planets and major planets?
- Dwarf planets are smaller
- elliptical orbits
describe the rotation and orbits of all large bodies in our solar system
what is the exception?
all orbit and rotate in the SAME DIRECTION and nearly SAME PLANE
- counter clockwise from above
VENUS rotates in the opposite direction (clockwise from above)
does the moon orbit the same way as all large bodies?
yes
does the sun rotate the same way as all large bodies?
yes
what % of the solar system’s mass is the sun?
> 99.9%
where does most of the mass of the sun come from? what percent?
98% He and H by mass
is the sun gaseous or solid?
gaseous
how does temp and pressure change as you go deeper in the sun?
temp and pressure increase with depth
what process occurs in the sun?
nuclear fusion (H –> He)
how much H is converted to He? how much He is produced? where does the remaining mass go?
600 million tons of H converted to 596 million tons of He
the remaining 4 million tons converted to energy via E = mc^2
if the sun is losing so much H in fusion, how can the sun still survive?
loses lots of H but there is A LOT of H in the sun that can be used
describe the composition of mercury?
made of metal and rock with large IRON core
how do we know mercury has an iron core?
indicated by its high density
how does the size of mercury compare to other planets?
mercury is the smallest of the 8 major planets
what is a word to describe the environment of mercury? why?
DESOLATE –> no volcanoes, wind, rain
describe the atmosphere of mercury and 3 things that this indicates
MERCURY HAS NO ATMOSPHERE
- cannot dissolve asteroids or meteoroids
- cannot scatter sunlight or cause colour
- cannot insulate
what is the consequence of mercury not being able to dissolve asteroids or meteoroids?
lots of craters on mercury
what is the consequence of mercury not being able to scatter sunlight or cause colour?
can see stars during day time
what large structures are present on mercury? what does this indicate?
has large, steep cliffs
indicates past geological activity
describe the temperatures of mercury during the day and at night
425C during day
-150C during night (even though right next to sun)
describe the rotation pattern of mercury
tidal forces from the Sun have forced Mercury into an unusual rotation pattern
describe the size of venus
nearly identical size as Earth
describe venus rotation
rotates very slowly in opposite direction of Earth
are days on venus long or short?
days on venus are very long
which direction does the sun rise? which direction does the sun set?
the sun rises in the west, sets in the east
why is the surface of venus hidden? what allowed us to see it?
the surface of venus is hidden by dense clouds
could learn about surface once we used cloud-penetrating radar
describe the greenhouse effect on venus and why it occurs
Lots of heat trapped due to thick atmosphere containing CO2
small wavelengths from the sun can come in and are absorbed by rocks, then released as large wavelengths which cannot escape –> stay inside the atmosphere
what is the temp of venus at night and during day?
470C during day and night
3 reasons why Earth is a unique planet
- O2 to breathe
- O3 to shield surface from solar radiation
- abundant surface water to nurture life
why are there pleasant temperatures on Earth?
atmosphere contains just enough CO2 and water vapour to maintain a moderate greenhouse effect
describe the size of mars relative to Mercury and the moon
Mars is larger than Mercury and the moon
describe the size and mass of mars relative to Earth
Mars is 1/2 diameter of Earth and 10% mass of Earth
how many moons does Mars have?
what are their names?
where could they have come from?
Mars has 2 small moons
Named Phobos and Deimos
May have been asteroids that were captured in orbit
describe the atmosphere of Mars
poisonous
what are 3 land features of Mars?
- Giant volcanoes
- Many canyons
- Polar caps
what is an indication of life being on Mars at one point?
water flowed at one point
what are the 2 types of planets? what is their size and relative distance to sun?
- terrestrial: rocky, small, close to sun
- Jovian: gaseous, large, far from sun
describe the densities of terrestrial vs jovian planets
Terrestrial = higher average density
Jovian = lower average density
describe the composition of terrestrial vs Jovian planets
Terrestrial = rocks and metals
Jovian = H, He, H compounds
describe the surface of terrestrial vs Jovian planets
Terrestrial = solid surface
Jovian = no solid surface
describe the presence of moons and rings in terrestrial vs Jovian planets
Terrestrial = few (if any) moons, no rings
Jovian = many moons, rings
describe the temperature of terrestrial vs Jovian rings
Terrestrial = warmer surfaces
Jovian = cooler at cloud tops
describe the distance btwn Terrestrial planets vs Jovian planets
Terrestrial = closer together
Jovian = further apart
describe the location of jupiter
much further from Sun –> must pass thru asteroid belt
describe the mass and volume of jupiter relative to earth
Mass: 300x larger than Earth
Volume: 1000x larger than Earth
describe the composition of jupiter
mostly H/He
does Jupiter have rings?
yes, it has faint rings
how many moons does Jupiter have?
80
what are Galilean moons? what are their names?
Galileo saw Jupiter’s moons
A) Io
B) Europa
C) Ganymede
D) Callisto
what structures does Io have?
active volcanoes
what is unique about Europa?
icy crust that may hide subsurface ocean
what is unique about Ganymede?
largest moon in solar system
what is unique about Callisto?
large moon, cratered “ice ball”
describe Saturn’s distance from the sun compared to that of Jupiter
Saturn orbits 2x as far from the sun as Jupiter
what is the size of Saturn relative to the other planets in our solar system?
2nd largest planet in our solar system
only slightly smaller than Jupiter by diameter but has lower density so lower mass
describe the composition of Saturn
mostly H/He
what is spectacular about Saturn?
has spectacular RINGS
What are Saturn’s rings made of?
made of small chunks of ice and rock
what is the name of one of Saturn’s moons? explain
Titan
only moon in solar system with thick atmosphere –> cloudy
surface temp = -180C
what is the size of Uranus compared to Jupiter, Saturn, and Earth?
Smaller than Jupiter and Saturn
Larger than Earth
what is the composition of Uranus?
H/He gas and hydrogen compounds (H2O, NH3, CH4)
What is a unique feature about Uranus? what causes this and what does it lead to?
has an EXTREME AXIS TILT
caused by cataclysmic collision during formation
leads to extreme seasonal variations
describe daylight and nighttime for uranus
daylight for 42 years, night for 42 years
describe the size and composition of Neptune to Uranus
Neptune is slightly smaller than Uranus but larger density so larger mass
similar composition to Uranus
describe the axis tilt of Neptune
no axis tilt
describe an example of Neptune’s moon, its surface and orbit
Triton
icy surface that spews N2
orbits in opposite direction to direction that Neptune orbits
what are 2 examples of dwarf planets?
- Pluto
- Eris
what is the composition of dwarf planets? why?
icy, comet-like composition
dwarf planets have a circular orbit so they remain icy bc they stay far away from the sun at all times
describe the difference btwn dwarf planets and comets
dwarf planets have circular orbit so they remain icy bc always far away from sun
comets have elliptical orbit so it moves close to sun and ice vapourizes, then moves away from sun to become icy
dwarf planets are similar size to _______
dwarf planets are similar size to Pluto’s moon Charon
how does the temperature of planets change the further away you get from sun?
temp of planets DECREASES the further away from the sun you get
how does a planet’s distance from the sun affect the time it takes a planet to rotate?
the time it takes a planet to rotate is NOT dependent on the distance from the sun
how can we learn about the scale of the solar system?
- measure apparent position of Venus on the sun from 2 locations on Earth
- use trig to determine Venus’ distance from the distance btwn the 2 locations on earth
what are 4 types of missions that can be used to probe planets in our solar system?
- Flyby missions
- Orbiter missions
- Probe and lander missions
- Sample return missions
what are flyby missions? what are 3 benefits and 1 downside?
flies by a planet ONCE then flies away
BENEFITS
1. Cheaper
2. Lack of friction and air drag in space allows it to maintain its trajectory without fuel
3. Can use speed of each planet as a gravitational SLINGSHOT to bend its path and speed it up (like Voyager 2)
what are orbiter missions? 1 benefit, 1 downside
goes in orbit around another world
benefit: more time to gather data
downside: cannot obtain detailed info about its surface
what are probe and lander missions?
land on surface of another world and explore the surface in detail
what are sample return missions? 2 examples
land on surface of another world and gather samples, then return to Earth
- Apollo –> moon
- Hyabusa –> asteroid
