Space Physics Flashcards
What is the universe made up of?
billions of galaxies
What does each galaxy contain?
hundreds of millions of stars
What do we have within our solar system?
- one star (the sun)
- 8 planets and the dwarf planets that orbit the sun
- asteroids and comets that also orbit the sun
- moons that orbit planets (natural satellites)
Give a brief description to how the solar system was formed.
1) Sun formed from the nebula ( cloud of dust and gas) which was pulled together by gravitational attraction
2) as dust and gas were drawn together, they collided, increasing the temperature and creating a protostar
3) As more material were drawn together gravity, these collisions increased until the temperature was high enough for hydrogen nuclei to fuse together = helium and a main-sequence star is formed (nuclear fusion)
4) material not drawn into the sun remained in orbit around the sun and formed the planets and other objects in the solar system
How is the core of the Sun kept hot?
the energy released by nuclear fusion
What is the sun stability the result of?
- the fusion energy trying to expand the sun
- gravity acting inwards trying to collapse the sun
The lifecycle of a star depends on what?
its size
what do small stars, large stars and larger stars become?
small stars = black dwarf stars
large stars = neutron stars
largest stars = black holes
What is the star cycle for a small star?
1) the hydrogen in the star begins to run out which means that the outward force due to fusion energy is less than the inward force due to gravity - this causes the star to collapse inwards
2) star expands to become a red giant
3) it then becomes unstable and ejects its outer layer of dust and gas. this leaves behind a hot dense solid core - a white dwarf
4) this will cool down, it emits less and less energy eventually becoming a cold black dwarf
What is the star cycle for a large star?
1) the hydrogen in the star begins to run out which means that the outward force due to fusion energy is less than the inward force due to gravity - this causes the star to collapse inwards
2) Sun expands to become a red supergiant. Helium fusion within this red supergiant allows for the production of nuclei as heavy as iron
3) Nuclear fusion is eventually no longer carried out by red supergiant. As the core of the red supergiant cools down, the pressure forcing it outwards will decrease and will no longer be strong enough to balance the inwards force of gravity.
4) this cause the star to shrink rapidly, which causes a huge increase in its core temperature and the star explodes in a supernova
5) this releases tremendous amounts of energy and scattering material of the star into space
6) the exploding supernova throws the out layers of dust and gas into space, leaving a very dense core - neutron star
What is the star cycle for a larger star?
1) the hydrogen in the star begins to run out which means that the outward force due to fusion energy is less than the inward force due to gravity - this causes the star to collapse inwards
2) Sun expands to become a red supergiant. Fusion of helium within this red supergiant allows for the production of nuclei as heavy as iron
3) Nuclear fusion is eventually no longer carried out by red supergiant. As the core of the red supergiant cools down, the pressure forcing it outwards will decrease and will no longer be strong enough to balance the inwards force of gravity.
4) this cause the star to shrink rapidly, which causes a huge increase in its core temperature and the star explodes in a supernova
5) this releases tremendous amounts of energy and scattering material of the star into space
6) if the star is massive enough, it will become a black hole
what is a black hole
a super dense point in the universe and has such a large gravity that even light can’t escape
What happens in a supernova?
what is formed?
starts are able to form elements heavier than iron and eject them into the universe to form new planets and stars
how do fusion processes lead to the formation of new elements?
- include how the universe was before stars
before stars, the only element in the universe was hydrogen
fusion processes in stars created all of the elements in the periodic table
all stars fuse hydrogen into helium
bigger stars then fuse helium into lithium and other lightweight elements, up to and including iron
during a supernova, the amount of energy released is so great that the temperature and pressure is high enough to force nuclei together to create elements heavier than iron
what do planets orbit
How do planters and satellites maintain their circular orbits
the sun
through the gravitational force (centripetal force) between them and the sun
