Topic 7 - Astronomy Flashcards
(20 cards)
Why does the weight of any body differ between the surface of other bodies?
The gravity has different strengths, as mass determines the amount of gravity present
Name all solar bodies in our solar system
Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Dwarf Planets, Asteroids, Comets & Natural Sattelites
Name all planets in order from closest to furthest from the sun
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
Name and explain the 2 theories about the structure of the Solar System
Geocentric - The planets and their satellites orbit around the earth
Heliocentric - The planets and their satellites orbits around the sun
Describe the orbit of a planet
Roughly circular, may be eliptical.
Describe the orbit of a comet
Highly eliptical, an almost complete egg shape
Explain for circular orbits how the force of gravity can lead to changing velocity of a planet but unchanged speed
The force of gravity acts towards the centre of the circular orbit and causes acceleration in that direction
Explain how for a stable orbit the radius must change if the orbit speed changes
If the speed increases the radius must decrease and vice versa to maintain a stable orbit
Explain the steady state theory
In the steady state theory, the universe is expanding, with the density of its contents remaining the same
Explain the big bang theory
In the big bang theory, the universe is expanding and the density of its content decreases
What evidence is there that the big bang theory is an accurate theory
The red shift of distant stars are redshifted, and almost none are blueshifted, which can only happen when a galaxy is moving away (redshift)
If a wave source is moving relative to an observer, there will be a change in the colour of the wave source. Why does this happen?
Because the wave source is either closer or further away from the observer, the further away you are from the source, the longer the wavelength is, which will redshift the waves, and vice versa
Describe the redshift in light recieved from galaxies at different distanced away from the Earth
The redshift in light recieved from galaxies at different distances away from the earth is redshifted when it’s further away, because the waves coming to Earth are longer
The big bang and steady state theories account for the redshift of galaxies. How?
The big bang theory explains redshift of the universe, as the universe expands from a single point, the space expands, light waves stretch, causing redshift
The steady stage theory accounts for the redshift of galaxies, the universe stays the same overall with continuous matter creation. Light still stretches causing RS
How did the discovery of the CMB radiation lead to the big bang theory becoming the currently accepted model
The CMB is leftover heat from the early universe, spread evenly in all directions. Its discovery matched Big Bang predictions of a cooling, expanding universe
Describe the evolution of stars of similar mass to the sun through the following stages
a) Nebula
b) Main sequence star
c) Red giant
d) White dwarf
Nebula -> Protostar -> Main Sequence Star -> Red giant -> White dwarf
Explain how the balance between thermal expansion and gravity affects the life cycle of stars
Thermal expansion forces all of the mass of the star outwards, while the gravity of the mass of the star is pulling it back in. When these forces are balanced, a star is formed
Describe the evolution of stars with a mass larger than the Sun
Nebula -> Protostar -> Main Sequence Star -> Red Supergiant -> Supernova
After a supernova it can become either a Black Hole or a Neutron Star
Describe how methods of observing the universe have changed over time.
Our methods of observing the universe has changed over time, as a long time ago, we would just look up at the sky and observe. Then after the invention of the telescope, people could get a zoomed in version of the thing they were observing
Give 2 advantages and disadvantages of telescopes being located outside the Earth’s atmosphere
Advantages:
1. It allows for an unobstructed view
2. The earths atmosphere can block & distort certain waves such as X-Ray
Disadvantages:
1. It is extremely difficult to build, launch and maintain
2. Repairs are difficult to pull off
