Space Physics Flashcards
(38 cards)
Describe the structure of the Solar System (sun and planets) - Space Physics
The Sun is the largest object in the solar system, with a huge gravitational field which keeps the planets orbiting around it
What happens to the temperature of a planet, and the time to orbit the Sun as the distance of planets from the Sun increases? - Space Physics
The temperature of the planet decreases, whilst the time taken to orbit the sun increases
What is a satellite? - Space Physics
A satellite is a body that orbits a planet (eg moon/communication satellites)
What are asteroids? - Space Physics
Asteroids are small objects which orbit the sun elliptically (in oval shaped) made from large metals and rocky materials
What are comets? - Space Physics
Smaller, rocky objects also made from dust and ice. As they near to the Sun, they vaporise producing a gas and distinctive tail
What happens in nuclear fusion in the Sun? - Space Physics
Hydrogen nuclei join together to form helium nuclei, which emits energy as radiation
What happens if objects in orbit travel too fast/slow? - Space Physics
If the satellite moves too quickly, the gravitational attraction will be too weak. The object will move into space.
If the satellite moves too slowly, the gravitational attraction will be too strong, and the object will move back to Earth
What is a stable orbit? - Space Physics
A stable orbit is an orbit at which the object is moving at just the right speed to remain in the Earth’s orbit
Why does the velocity of an object in orbit constantly change even if it’s speed is constant? - Space Physics
Velocity is a vector quantity, meaning that it has a direction which constantly changes even if the speed remains the same
Why do objects in small orbits travel faster than objects in larger orbits? - Space Physics
As 2 objects are closer together, they have a stronger force of gravity between them. The greater force means GREATER ACCELERATION. Greater acceleration means GREATER VELOCITY
What are the 2 types of orbit around the earth? - Space Physics
Polar orbits (around the poles) and geostationary orbits (orbiting at the same rate as the planet)
How long does a geostationary satellite take to orbit Earth? Why is this? - Space Physics
24 hours
Because a geostationary satellite orbits at the same rate as the Earth
What is a nebula? - Space Physics
A cloud of gas (mainly hydrogen) and dust in outer space, which can collapse under gravity to form a protostar
What is a protostar? - Space Physics
A mass of gas which is spinning, yet is not yet fast enough for nuclear fusion to occur
What is a main sequence star? - Space Physics
A stable stage in the life cycle of a star, in which nuclear fusion occurs, fusing hydrogen nuclei into helium which releases energy. The outwards radiation and inward gravitational force are balanced, keeping the star stable
What is the difference in low mass and high mass stars? - Space Physics
After being a main sequence star…
Low mass stars -> red giant, white dwarf, black dwarf
High mass stars -> red super giant, supernova, neutron star/black hole
What is a supernova? - Space Physics
Elements heavier than iron are fused at this stage. A large explosion at the end of a star’s life which distributes elements formed by nuclear fusion across space
How is a protostar formed? - Space Physics
Gravity begins to pull the dust and gas of a nebula together and gets warm, starting to spin
How is a main sequence star formed? - Space Physics
The protostar heats up and begins to spin. When it is hot enough and spinning enough, nuclear fusion of hydrogen into helium occurs, emitting energy
What happens to form a red giant star? - Space Physics
When all hydrogen has been used up, larger nuclei begin to be fused together and the core of a star becomes unstable and it begins to contract. The outer areas of the star expand
How does a white dwarf form? - Space Physics
When all nuclear reactions are over, a small star like the sun will contract under the pull of gravity. The star fades, becoming white as it is still hot
What is a black dwarf? - Space Physics
A black dwarf is a white dwarf which has contracted further and cooled
How does a main sequence star remain the same size? - Space Physics
The gravitational attraction which collapses the star is balanced by the radiation emitted which expands the star
What causes all the naturally occurring elements in the universe to form? How are they on Earth? - Space Physics
All naturally occurring elements are formed by nuclear fusion reactions. They are found on Earth as a supernova explodes, throwing elements out across the universe
