Space: Formation of the Solar System Flashcards
What were stars initially formed from And what was it called?
Nebula - Clouds of gas and dust
How it a protostar formed?
- force of gravity pulls the dust and gas together
- temperature rises as star becomes denser and more particles collide
- when temperature high enough —> nulcei of hydrogen atoms fuse together to form helium nuclei —> NUCLEAR FUSION
- fusion releases huge amounts of energy —> keeps the core of the star hot.
- A star is born
What is a main sequence star?
- star enters a long stable period where outward pressure from nuclear fusion tries to expand but it is balanced by the inward force of gravity that pulls everything together
- typically lasts severall billion years s.g. Sun
What will happen with the hydrogen in a star runs out?
- smaller star will swell into a Red Giant/ bigger star - Red Super Giant
- fusion of helium (and other light elements )occurs —> forms heavier elements, up to iron, the core of star
What happens when there are no more light elements in the core of a red giant and what does it form?
-White Dwarf
- fusion stops, no more radiation released
- collapses under own gravity
- as it collapses—> heats up + turn from red to yellow to white + ejects outer layer of dust and gas
- leaves hot, dense solid core
Why does a white dwarf become a black dwarf?
- cools down, emits less energy and light
- when no longer sufficient energy left —> black dwarf
What happens when a red super giant collapses?
- matter surrounding star’s core compresses, but reverses in a explosion called a SUPERNOVA
- form elements as heavy as iron, ejects into universe to form new planets and stars
What 2 possible stages occur after a supernova, and why do they differ?
- Neutron Star OR Black Hole
- exploding supernova throws outer layers of dust and gas into space
- leaves a very dense core called a neutron star
- If star is massive enough —> black hole —> super dense point in space where even light can’t escape from
What elements do stars like the Sun fuse together and what into?
Hydrogen nuclei into helium and similar small nuclei into carbon nuclei
What elements do red giants fuse and what into?
Helium nuclei and small nuclei into larger nuclei
What can’t elements heavier than iron be formed in the stages before the supernova?
Too much energy is needed
Why can heavier elements be formed in a supernova?
- enormous force of collapse fuses small nuclei into nuclei bigger than iron nuclei
