Unit 4 Solar System Flashcards
What year was Pluto Excluded as a planet
2004
What is the order of the planets from the sun outwards
sun mercury venus earth mars Jupiter saturn Uranus Neptune Pluto
How do we represent the earth?
pinhead
1mm ball
15,000km in one mm
How do we represent the moon?
a millet seed, 3 cm far from the pinhead
How do we represent the sun?
10 cm diameter croquet ball
- distance between ball and pinhead is 10 m
What does the 9km^2 lot contain and what is it?
1 croquet ball 2 nuts 2 peas 2 pinheads 3 smaller grains - how we represent and scale the solar system - it is mostly empty
What is the heliosphere
the region surrounding our sun and solar system
- it is 1000m
How many years ago did the solar system form and how
- 5 billion years ago from a vast cloud of interstellar gas and dust called the solar nebula
- the main source of nebula’s matter is old stars which shed parts of their bodies
- the final size of our solar system is by far smaller than it was initially
What are the two main factors in the solar system formation
- gravitation (pull everything together)
- rotation (push everything apart)
- the gas becomes compressed, the temperature rises and weight is pulled together (gets faster when closer) , endless numbers of collisions forming dust clumps
- the strongest planets survive
How many young circum-stellar disks are in the Orion nebula
2
both of which are less than 10 million years old
- there are two potential planetary systems
How did collisions in the early solar system lead to planet formation
- Planetesimals (10 km objects)
- Protoplanets- the result of accretion
- a few planets formed
How old is our moon
- 2.6 billion years old
How did lunar craters get on our moon
- most lunar craters were formed during the moons first 700 million years pf existence when the rate of bombardment was much greater than it is now.
- additionally, all foot prints on the moon will likely be there forever because there is no water on the moon to wash them away
What is the composition of the earths atmosphere
- nitrogen : 78%
- oxygen: 21%
- noble gases: 0.94%
-carbon dioxide: 0.03%
traces of other gases
What is the earths atmospheric mass
- 15x10^18 kg
- it falls by half ever 5.5 km
Where does the majority of the earths atmospheric mass lie
75% of the atmospheric mass lies within 11km lower layer
- the troposphere
Where is the earths ozone layer
- in the stratosphere
20-30 km
What is the Ozone cycle
Oxygen atoms cycle between oxygen molecules and ozone. The sun’s rays split oxygen molecules (O2) apart into individual O atoms. These O atoms then join with an oxygen molecule (O2) to make Ozone (O3). As the ozone absorbs UV rays, it splits into O and O2.
- the ozone layer protects us from harmful rays
Why is the earth so hot inside?
- collision between chunks of rock our planet was formed of
- internal friction due to tides
- heat released because of nuclear fission of element like uranium
What are the layers of the earth starting at the centre
- solid inner core due to pressure, iron rich core
- liquid outer core
- rocky mantle
- crust (rock, floats on denser material below)
What is the main source of the earths internal structure
- seismic waves analysis
How thick is the continental crust and ocean crust
Continental : 20-40km
Ocean: 15-20km
What is another name for the earths crust
- lithosphere
What is the Mid-Atlantic Ridge
- created by lava seeping up from the earths interior
