Space (2) Flashcards
Lifecycle of a star (red giant)
- form from a cloud of dust called a nebula
- gravity puts the dust and gas under immense pressure and heat to form a protostar
- eventually hydrogen nuclei fuse into helium
- A star enters a long stable period where the inward force of gravity and outward force from fusion are equal (main sequence star)
- when hydrogen runs out, the star swells into a red giant
- fusion of helium and other elements up to iron occurs
- a red giant becomes unstable and ejects a layer of dust and gas leaving behind a white dwarf
- This cools into a black dwarf
Lifecycle of a star (red supergiant)
- form from a cloud of dust called a nebula
- gravity puts the dust and gas under immense pressure and heat to form a protostar
- eventually hydrogen nuclei fuse into helium
- A star enters a long stable period where the inward force of gravity and outward force from fusion are equal (main sequence star)
- when hydrogen runs out, the star swells into a red giant
- fusion of helium and other elements up to iron occurs
7.red supergiants glow brightly and expand under greater fusion - They’ll explode to form a supernova which forms elements heavier than iron
- the supernova leaves a neutron star or a black hole depending on the star’s size
What objects are found in the solar system
The sun, planets, moons, comets, asteroids
How do planets orbit the sun
planets move in a circular motion, so they are constantly changing direction and therefore continually accelerating and constantly changing velocity
The force acting on the planet towards the centre of its orbit is gravity
how does size of orbit affect speed of object
the closer to a star or planet the object is, the stronger the gravitational force becomes
the stronger the force, the faster the object needs to be moving to remain in orbit
Faster-moving objects will orbit on a smaller radius than larger ones
What is red-shift
who theorised it
Redshift is when light from an object moving away shifts towards the red end of the visible light spectrum.
It happens because light waves stretch, increasing their wavelength.
Distant galaxies show redshift, meaning they are moving away from us.
The further a galaxy is, the greater its redshift.
This supports the idea that the universe is expanding, linking to big bang theory
Edwin Hubble’s Law states that galaxies further away are moving away faster.
What is the Big Bang theory
when did it happen
evidence for it
The Big Bang Theory states that the universe began from a single, extremely dense and hot point.
Around 13.8 billion years ago, this point rapidly expanded, creating space and time.
The universe continues to expand today.
Cosmic Microwave Background Radiation (CMBR) is leftover heat from the early universe.
The abundance of light elements like hydrogen and helium matches predictions from the theory.
What is dark matter
An undetectable substance. It must exist for gravitational orbits to work and for the universe to remain stable
