8 - ASTROPHYSICS Flashcards
What is the definition of a universe?
The universe is a large collection of billions of galaxies.
What is the definition of a galaxy?
A galaxy is a large collection of billions of stars.
Where is our solar system?
Our solar system is in the Milky Way galaxy.
What does the size of an object’s gravitational field strength depend on? Give an example.
It depends on the objects mass. A star has a huge mass, and so will have a large gravitational field strength.
Why does the moon’s gravitational field strength differ from earth’s?
The moon has less mass than earth, and so its gravitational field is much weaker. This is why we can jump higher on earth, and objects fall more slowly, as there is a weaker gravitational force.
How does the size of the radius of a planet affect the strength of the gravitational field?
A planet with a large radius will have a weaker gravitational field at its surface, as the surface is further away from the centre of the planet.
Why does your weight vary across planets?
Since weight = mass x g, your weight is dependent on g. G is varied due to how large the radius is, and how much mass the planet contains.
What does our solar system consist of?
- The Sun
- 8 Planets - Mercury,Venus,Earth,Mars,Jupiter,Saturn,Uranus,Neptune.
- The planets natural satellites (The moon.)
- Dwarf planets.
- Comets and asteroids.
Describe the orbits of comets?
Comets have highly elliptical orbits, with the sun at one focus. When they come close to the sun, they speed up due to a higher gravitational force. They also develop bright tails that point away from the centre of the sun. These are caused by tiny ice crystals that melt and break off from the comet, and reflect the bright light of the sun.
Describe the orbits of moons?
Moons follow a circular orbit around planets.
Describe the orbits of Planets?
Planets orbit in ellipses around the Sun.
How can stars temperature be classified according to their colour?
The order from coldest to hottest is.
Red - Orange - Yellow - White - Blue
Describe the evolution of stars (similar mass to the sun), in order of processes.
Nebula - Star - Red Giant - White Dwarf
