Space physics

our solar system

made up of 8 planets and their natural satellites (the moon), dwarf planets, asteriods and commts

mercury venus earth mars jupiter saturn uranus neptunes

my very educated mother just served us nachos

our system is part of the milky way galaxy, the milky way is made up of billions of stars

evolutions of the stars

life cycles of a star

1) a cloud of dust and gas called nebula is pulled together due to graviational atttraction and becomes a PROTOSTAR

2) The protostar is pulled together by gravity and the particles in the protostar collide more frequently, more energy is trasnferred from gpe store to thermal energy store of the particles, and thus temp increases

when its hot enough, fusion of hydrogen nuclei occurs forming helium nucliei and realeasing huge amounts of energy

the protostar then becomes MAIN SEQUENCE star and the inwards force of gravity and outward forces of high pressures balance and the star is stable

IF THE STAR IS THE SIZE OF THE SUN: it becomes a red giant and over time hydrogen is used up through fusion and there is a a larger nuclei, thus the star expands causing a red giant

then it turns to a white dwarf, as the nuclear reactions stop and the star contracts due to gravity and it becomes a white dwar

THEN its a black dwarf, as all thermal energy is radiated, the white dward cools down into this

LARGER THAN THE SUN:

Red super giant explodes to a supernova, either a neutron star, or if it was MASSIVE it becomes a black hole

evolution of stars

nuclear fusion reactions occuring in stars produce all naturally occuring elements, H2 nuclei fuse to form hellium nuclei

more fussion reactions occur in stars with large masses forming small nuclei

when the star is a red giant, or a red supergiant, hellium and other small nuclei fuse together to form larger nuclei

when the supernova explodes, it distributes the elements all over the universe (any elements HEAVIER than iron) - how they ended up on earth!

orbits

objects orbit another body due to gravity to provide an attractive force

the moon orbits a planet and has a circular orbit

planet orbits sun and has almost cirular orbit

artifcial satellite orbit the earth or any other bodies in the solar system and have circular orbits

when an object orbits a body in a circle at constant speed, the direction of its motion constantly changes, this means the velocity is constantly changes because velocity if a vector and has magnitude AND direction

even though the magnitude stays the same, the direction changes so velocity changes as well

orbit

smaller orbit, bigger velocity

the force due to gravity depends on distance

smaller the distance, bigger their gravitational attraction

bigger this sttraction, bigger the acceleration in the object

bigger acceleration, greater change in the velocity

objects in small orbits travel faster than objects in large orbits

to change orbital speed, we must change the radius of the orbit to ensure a stable orbit

Red shift

if a wave source moves realtive to an observer, theres a change in observed freq and wavelength

as the wave source moves towards an observer, the wavelength decreases, and frequency increases

as the wave sources then moves away from observer, wavelegnth increases and freq decreases (lower pitch)

the futher away the galaxy, the faster they move, and the bigger the observed increase in wavelength, we call this red shift

wavelength shifted to longer wavelength spectrum *red)

since 1998, scientists have observed light from supernovae suggesting distant galaxies are receeding even faster

big bang theory

redshift is evidence, as the observation of red shifted light when observing distant galaxies shows us that the universe is expanding

BBT- The theory the universe was once extremely hot and dense region, and a huge explosion occurs causing the universe to expand

we still dont understand

dark mass and dark energy