Redshift
The observed increase in the wavelength of the light emitted by
distant galaxies. The more distant the galaxy, the faster it is moving and so the
bigger the observed increase in wavelength.
First 3 stages of Life cycle of star
Stars initially form from a cloud of dust and gas called a nebula
Force of gravity pulls the dust and gas together to form a protostar.
The temperature rises as the star gets denser and more particles collide. When temperature gets high enough hydrogen nuclei undergo nuclear fusion to form helium nuclei. Which releases lots of energy keeping the core of star hot
Star enters a long stable period where the outward pressure caused by nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards. In this period its called a main sequence star and it typically last several billion years
2nd 3 stages of the life cycle
Eventually hydrogen will run out. It then becomes a red giant or a red super giant. It’s red because the surface cools. Fusion of helium occurs. Heavier elements up to iron are created in the core
A star like the sun becomes unstable and ejects its outer layer of dust and gas. Leaving behind a hot dense solid core. White dwarf
When it cools down it emits less energy and is then called a black dwarf.
Last 2 stages of star cycle
Red super giants grow brightly again as they undergo more fusion forming elements as high as iron. Theyll explode in a supernova making elements heavier than iron. Star life cycles produce all elements
The supernova ejects all the dust and gas into space leaving a dense core called a neutron star or if the star is big enough a black hole
Planet
Moon
Definition
Planet- Large objects that orbit a star but have a large enough gravity to have moons
Moons- Natural satellites that orbit planets
Big bang theory
That all matter occupied a small space in the universe a space that was very hot and dense
Then it exploded and space expanded and this continuouslly occured
