P8 Flashcards
What is a galaxy?
A huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity
What are the different parts of our solar system? (5)
- Sun. 2. 8 planets. 3. Dwarf planets. 4. Natural satellites. 5. Moons.
What are the simple stages of a normal star’s life? (6)
- Nebula. 2. Protostar. 3. Main sequence star. 4. Red giant. 5. White dwarf. 6. Black dwarf.
What is the life cycle of a normal sized star? (7)
- A cloud of dust and gas (nebula). 2. Then pulled together by gravitational attraction (protostar). 3. Hydrogen nuclei undergo nuclear fusion to form helium nuclei (a star is born). 4. Main sequence star - stable as the outward force from fusion is equal to the inward force from gravity. 5. Hydrogen runs out so it expands (heavy elements fuse) and a red giant is formed. 6. Ejects outer layer of dust and gas and shrinks (white dwarf). 7. Cools down and forms black dwarf.
What are the simple stages of a massive star? (6)
- Nebula. 2. Protostar. 3. Main sequence star. 4. Red super giant. 5. Supernova. 6. Neutron star or black hole (based on size).
What is the life cycle of a massive star? (7)
- A cloud of dust and gas (nebula). 2. Then pulled together by gravitational attraction (protostar). 3. Hydrogen nuclei undergo nuclear fusion to form helium nuclei (a star is born). 4. Main sequence star - stable as the outward force from fusion is equal to the inward force from gravity. 5. Hydrogen runs out so it expands (heavy elements fuse) and a red supergiant giant is formed. 6. They expand as more fusion occurs with heavy elements (releasing energy) which leads to a supernova. 7. Supernova throws outer layers and becomes neutron star or black hole - depending on the size.
What does gravity allow planets and satellites to maintain?
Their circular orbits.
What are the differences between planets; moons and artificial satellites?
Planets orbit stars. Moons orbit planets and are natural satellites. Artificial satellites orbit any celestial body and are man made and launched into space.
What are the two types of satellites?
Natural and artificial.
What is a circular orbit?
A circular path that revolves or goes around an object. Often caused by gravity
How does the force from gravity lead to a changing velocity but not a changing speed for circular obits?
Velocity is speed with a direction. The speed stays the same as it orbits. The direction changes (due to the pull from gravity) when there is a circular orbit so the velocity must change. This is because gravity acts perpendicular to the object’s motion only altering its direction - not its speed.
For a stable orbit why must the radius change if the speed changes?
For a stable orbit; the radius must change if the speed changes to maintain the correct balance between the gravitational force and the object’s inertia. If the speed increases; the radius of the orbit must also increase to reduce the gravitational force and prevent the object from spiraling inwards.
What is red shift?
The shift in the wavelength of light from distant objects toward the red end of the spectrum
What red shift tells us about the Big Bang Theory?
Galaxies and suns are moving away from us at an increasing velocity . This means that space itself is expanding - supporting the Big Bang Theory.
What is the Big Bang Theory?
One theory for the creation of the universe. Suggests the universe began from a very small; hot and dense region.
What is dark mass?
Makes up part of our universe but is invisible to telescopes because it doesn’t interact with light or other electromagnetic radiation.
What is dark energy?
A mysterious force that appears to be causing the expansion of the universe to accelerate. 68% of universe.
