Chapter 13 - Space Flashcards
What is the order of the eight planets from the sun outwards ?
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
Why do all the planets orbit the sun ?
They travel on the same plane in the same direction as a result of the gravitational force of the sun
What are artificial satellites ?
Objects put into space by humans
What are artificial satellites used for ?
- communications
- earth observation
- astronomy
- weather monitoring
How are stars formed ?
- Clouds of hydrogen gas and dust come together
- due to gravity
- this then changes to thermal energy and creates a protostar
How do we tell that the sun contains mostly hydrogen and helium ?
- use a solar absorption spectrum
- the wavelengths of hydrogen and helium will have the most black lines
How is the suns energy supplied ?
by the fusion of hydrogen into helium
Where and how are all naturally occurring elements formed ?
They are all made (except hydrogen) by nuclear fusion in the stars
Recall the stages of the life cycle of stars
- protostar
- main sequence
- red giant
- white dwarf
- black dwarf
Why is a star stable during the main sequence stage of it’s life ?
The outward force of thermal expansion is balanced by the inward force of gravity
What do more massive stars become after the main sequence ?
Red supergiants
What happens to massive stars when they are supergiants ?
There is an explosion in which the outer layers are ejected
What do you call the explosion of a supergiant and how bright does it shine ?
A supernova and the brightness of 10 billion suns
What may happen after the supernova ?
It may collapse more and form a neutron star or a black hole
Why can light not escape fro ma black hole ?
Because they are incredibly dense and have a very strong gravitational field
When did the big bang occur ?
14 billion years ago
Explain the big bang theory
- a big bang happened
- the universe quickly expanded then cooled
- cooling allowed protons and electrons and neutrons to from
- cooling continued and neutrons combined to form simple nuclei
- the temp dropped enough for hydrogen to form
Explain red shift as an argument for the big bang
- When we look at the light from distant galaxies it’s at the red end of the spectrum
- This tells us that the source is moving away from us
- therefore the universe is expanding
What does CMBR stand for
cosmic microwave background radiation
What is CMBR ?
It represents the after glow from the big bang. It has its own unique wavelength and can only be explained by the big bang.
What are exoplanets ?
Planets outside our solar system
How do we determine what a planets atmosphere is like ?
We use a solar absorption spectrum and see what the atmosphere consists of. ( planets with high oxygen in the atmospheres gives it a better chance that there may be life there)
What are the 4 difficulties of space travel ?
- flight time ( our spacecraft are too slow)
- engineering ( spacecraft too slow)
- logistics (spacecraft cant carry enough fuel or food)
- ethics ( chance of failure would be high, no rescue)
What are the distance to stars and galaxies measured in ?
light years
