Space And The Solar System Flashcards
What are dwarf planets?
Planet like objects that aren’t big enough to be called planets
What are moons?
Moons orbit planets in an almost circular orbit
What are artificial satellites?
Human built satellites that orbit the earth in fairly circular orbits.
What are asteroids?
Lumps of rock and metal that orbit the sun - they are usually find in the asteroid belt
What are comets?
Lumps of ice and dust that orbit the sun - they have highly elliptical orbits
What are meteors?
Particles broken off from a comet or asteroid that orbit the sun. It burns up as it enters the earth’s atmosphere, creating the effect of a shooting star
What is a planet?
Large objects that orbit our sun
Mercury, Venus, Earth, mars, Jupiter, Saturn, Uranus, Neptune,
What force causes the planets to move around the sun in almost circular orbits and to be constantly accelerating?
The Centripetal force which acts towards the centre of the circle.
This force would cause the object to fall towards whatever it is orbiting, but as it is already moving it just cause it to change direction.
What causes the object orbiting to travel in a circle?
The instantaneous velocity (right angle to the acceleration)
The force that allows this to happen is provided by the gravitational force (gravity) between the planet and the sun or plant and the satellite
What does gravitational field strength depend on?
The greater the mass and the smaller readies to surface area, the stronger the gravitational field strength
It also varies with distance as the closer you get to a star or planet the stronger the g force.
How do orbits remain stable?
The stronger the force, the larger the instantaneous velocity needed to balance it. So the closer you get to a star or planet,the faster you need to go to remain in orbit.
Faster moving objects will move in a stable orbit with a smaller radius that slower moving ones(what happens to one happens to the other)
What did Ptolemy think about the solar system?
A Greek astronomer who thought the solar system was geocentric. This suggested that everything orbited earth in perfect circles. The idea arose as people didn’t have telescopes but saw the sun and moon travel across the sky in the same way daily
What did Corpenicus think about the solar system?
A polish astronomer who thought the solar system was heliocentric - planets orbiter the sun in perfect circles
What was Galileo able to prove?
That the geocentric model was incorrect. Whilst looking at Jupiter through a telescope he realised moon orbited it - proving not everything orbited the Earth. Therefore our current accepted model is heliocentric but orbits are elliptical
What is the steady state theory?
That the universe has always existed as it is now and it always will do. It is based off the idea that the u inverse appears pretty much the same everywhere. As the universe expands, new matter is constantly being created to fill the gaps - so density remains roughly constant
What is the Big Bang theory?
Initially all the matter in the universe occupied a very small space which was extremely hot and dense- was a singularity
This then exploded producing energy, time and the creation of space. It started to expand and still is - giving the universe a finite age
What is the red-shift?
Red-shift/blue-shift is the process by which wavelengths of light from distant stars is lengthened or shortened. This is because stars more between emitting waves of light causing contractions of lengthening in the wavelength of light we observe
What wavelength is blue shift and which is red shift?
Long wavelength, lower frequency = red shift
Shorter wavelength = higher frequent = blue shift
Because almost all distant stars are red shifted, showing they are moving away from us, it is evidence for the universe expanding
What is the red shift evidence for?
Both the Big Bang and steady state theory support the idea that the universe is expanding and in doing so moving away from the observer, so as a singular piece of evidence is supports both theories.
What is CMBR?
Scientists have detected low frequency electromagnetic radiation coming from all parts of the universe. It is though to be left over heat and energy from the original explosion
What does CMBR support?
Supports the idea that the universe had a beginning and is why the Big Bang theory is currently our accepted model. The steady state theory also didn’t predict CMBR so is discredited
What are optical telescopes used for?
To see distant objects clearly by detecting visible light by using reflection and refraction
-to improve quality, increase the aperture and use a higher quality objective lens
Why is it hard to detect light?
The earth’s atmosphere gets in the way and absorbs wavelengths as does light pollution. It can also cause atmospheric distortion
What do more advanced telescopes do?
Detect different kinds of EM waves
- X-ray telescopes are a good way to ‘see’ violent high temperature events in space like exploding stars, radio telescope detected CMBR
- better quality lens, clearer image and larger aperture to allow more light in
