Space Flashcards
What’s the order of planets from closest to furthest away from the sun?
- Mercury = My
- Venus = Very
- Earth = Energetic
- Mars = Monkey
- Jupiter = Jumps
- Saturn = So
- Uranus = Urgently
- Neptune = Now
What is the solar system composed of?
The Sun, 8 planets, asteroids, comets and dwarf planets such as Pluto.
What does geocentric mean?
The idea was published by Ptolemy in 130CE.
- it was an earth centred model that tried to explain the motion of planets.
What does heliocentric mean?
The idea was published by Nicolaus Copernicus in 1543.
- it means sun centred because planets orbit around the sun.
What are natural satellites?
- formed by natural processes.
EXAMPLES: - the 8 planets in the solar system which orbit the sun.
- the moons which orbit planets in the solar system.
- comets which orbit the sun.
What are artificial satellites?
- they have been manufactured and have been launched into space from Earth using rockets.
EXAMPLES: - satellites in geostationary orbits around the Earth being used for global positioning satellite systems (GPS).
- satellites in low polar orbits around earth being used for weather monitoring and more.
- satellites sent from Earth to orbit and monitor the sun.
Compare the motion of Earth, Jupiter and Saturn as they orbit:
They all travel in circular orbits with a constant speed and changing velocity.
As the dist from sun increases, the orbital speed decreases.
The Earth has a higher orbital speed than Jupiter which ahs a higher orbital speed than Saturn.
What is the Big Bang theory?
The whole universe started as a tiny particle 13.8 billion years ago.
The universe expanded from this point in space.
The universe is still expanding today.
What is the Steady State theory?
The universe has always existed.
It is expanding, and new matter is being created as it expands.
What is Red Shift?
- when that objects emit light, such as galaxies, are moving away from us then the light they emit is ‘red-shifted’.
- the wavelengths from them when detected back on earth will be ‘stretched’.
- the spectral lines will be shifted further to the red end of the spectrum, compared to a stationary object on earth.
- the faster the galaxy is travelling away from us, the more these lines will be shifted to the red end.
- the furthest galaxies show more red shift then the ones nearer showing that the universe is expanding.
What is Cosmic Background Radiation?
- the ‘echo’ of the Big Bang.
- at the time of the Big Bang, this radiation would’ve been hot and intense.
- overtime, the radiation has cooled and is now very weak and at a temperature of -270 degrees C which is close to absolute zero.
- the fact that CMBR is detected in all directions and has the temp that it does, proves that the Big Bang was almost 14 billion years ago.
What is the Doppler effect?
When a wave is moving relative to the observer, there is a change in the observed frequency and wavelength of the waves.
How does this apply to a siren on a car?
When the car is travelling away from observer 1 (on the left), this stretches the sound wave out giving it a longer wavelength and lower frequency which gives it a lower pitch.
The driver of the car is not moving relative to the siren, so the pitch she hears stays the same all the time, as it would be for an external observer if the car was stationary.
When the car is travelling to observer 2 (on the right), this compresses the sound wave making the frequency higher so the pitch sounds higher to observer .
How do Red-Shift and the Doppler effect link?
The doppler effect also occurs for light waves:
- a light source moving away from the observer will have a greater wavelength and a lower frequency. It is ‘red-shifted’.
- a light source moving towards the observer will have a smaller wavelength and a higher frequency. It is ‘blue-shifted’
What stars are classed a low-mass stars?
Stars with masses up to 4 times the mass of the Sun.
What is the life cycle of a low-mass star?
1) The cloud of dust and hydrogen gas (a NEBULA), is pulled inwards by the force of gravity. As the dust and gas contracts the nebular gets hotter since work I being done to it.
2) Eventually, the dust and gas become hot enough for the hydrogen nuclei to fuse. Nuclear fusion leads to helium nuclei being produced and large amounts of energy. This star will begin to give out light and is a main-sequence star. Stars are MAIN-SEQUENCE stars for most of their lives. The inwards force of gravity is balanced by the outward force of thermal expansion.
3) When most of the hydrogen gas has been converted into helium, the star will expand and become a RED GIANT. When the core of this star collapses, other heavier elements are formed.
4) Eventually, all nuclear fusion stops due to elements that cause fusion being used up, and the star collapses to become a WHITE DWARF.
What is a high-mass star?
A star with a much higher mass than the sun that follows the same first stages of the life cycle, but each stage is shorter.
- When most of its hydrogen is used up, it forms a RED SUPER GIANT.
- At the end of this stage the star will explode as a SUPERNOVA.
- If what remains after the explosion is less than four times the mass of the sun it will be pulled together by gravity to form a very small, dense star called a NEUTRON STAR.
- More massive remnants form BLACK HOLES.
What do telescopes do?
Observe the visible light emitted by stars.
How have telescopes developed?
Greater magnification=
observe galaxies that are far away.
Record observations using photography=
we gather more data.
Can be made with greater precision=
we get clearer images.
Telescopes that can detect other parts of the electromagnetic spectrum=
we observe objects in space that emit more radio waves, infrared, ultraviolet or X-rays than visible light.
