Unit 2.5 - Stars and Planets Flashcards
What is the asteroid belt made up of?
Many rocky asteroids and dwarf planets.
Describe the orbit of a comet.
Comets have highly elliptical orbits, passing far outside of the Solar System.
Define a galaxy.
A large collection of stars
Name the stages in the life cycle of a low-mass star like our Sun.
Protostar -> Main sequence -> Red Giant -> White dwarf
Name the stages in the life cycle of a high-mass star.
Protostar -> Main sequence -> Red Supergiant -> Supernova -> Neutron star/black hole
Describe and explain what will happen in the next stage of the Sun’s life cycle.
Once it runs out of hydrogen it will fuse helium and then increasingly heavier elements. It will swell as the gas and radiation pressure exceed gravitational force.
Explain why the Sun is currently stable and remains the same size.
The outward forces of gas and radiation pressure are balanced with the inward force of gravity.
Describe and explain the final stage of the Sun’s life cycle.
Eventually, as it increases in mass but runs out of elements to fuse, the gravitational force inwards will exceed gas and radiation pressure and it will shrink.
Explain what happens to normal supergiants shortly after they reach this stage.
They run out of heavier elements quickly collapse due to gravity, exploding in a supernova.
Explain what happens to high mass supergiants.
They collapse to form neutron stars with extremely high density.
Explain what happens to the highest mass supergiants.
They will collapse into a black hole, a point of mass with such high density, and hence such high gravity that not even light can escape.
How are elements heavier than iron (e.g. uranium) formed
These elements cannot be formed by fusion, so they are formed during a supernova explosion and ejected into space.
Describe the formation of the solar system.
A large, spinning cloud of gas and dust (including elements left over from supernovae) was drawn together by gravity and collapsed to form a star and planets.
Explain why the planets closer to the Sun are rocky while those further away are gaseous.
Rocks are denser, and tended to gather closer to the Sun, while the lower density gases tended to gather at further distances from the Sun.
