Kategorier: Alle - gravity - elements

af Ahmed Elsharif 3 år siden

488

Life Cycle of a Star

Stars begin their existence as nebulas, vast clouds of gas and dust. The force of gravity pulls these particles together, forming a protostar. As the protostar accumulates more material, its density and temperature rise, leading to increased particle collisions.

Life Cycle of a Star

Life Cycle of a Star

A star starts off as a nebula

Over time the force of gravity pulls the dust and gas together (collapse) and forms a protostar
when more and more particles collide it gets bigger so its force of gravity gets even stronger , this causes the protostar to collect more gas and dust

the crevity squeezes the protostar into itself making it more dense, this means that the particles inside it collide more often

then when the temperature and pressure increase, hydrogen nuclei to form helium nuclei

this process is called nuclear fusion

this gives out huge amounts of energy keeping the core hot

at this point it gets called a main sequence star

while a main sequence star the outward pressure caused from the nuclear fusion is completely balanced with the inward pressure from gravity

eventually it will start to run out of hydrogen causing inward pressure to take over, then it will become so hot and dense and nuclear fusion can start up again, the star will then expand again

now, instead of just forming helium it will form heavier elements

the star will expand dependent on how big the original star was, if it was small - medium it will form into a red giant,if it was large it will form into a red super giant

Red Super Giant

red super giants under go even more nuclear fusion then before , then after going though several cycles of expansion and contraction, they explode

that causes it to from into a supernova ,

if the original star was very big this forms into a dense core called a neutron star but if it was completely massive it forms into a black whole

a super nova from elements even higher than iron, which is ejected across the universe.

Red Giant

after a short amount of time the red giant becomes unstable, and the outer layers and removes its outer layers this leaves a hot dense solid core which doesn't do any nuclear fusion

this is called a white dwarf

after a bit of time it gets cooler and darker as it releases all of its energy

finally it forms into a black dwarf because it has no more energy to release light

this can last for a long and very stable period, billions of years

this rasises the temputure of the proto star

A nebula is cloud of dust and gas