StarsWhat are they?

StarsA Star is a luminous ball of gas, mostly hydrogen and helium, held together by its own gravity. Nuclear fusion in its core creates energy and heat. There are many types of stars, all having relations to different stars. The colour of the star can mean many different things, what phase it is in, the temperature, or its composition.

The Birth Far in space, there are huge clouds of gas a dust. And if these clouds are massive enough, it will start to collapse. It will get denser and hotter, and eventually these particles will be brought so close, that they will start to fuse together. Thus is the “ignition” of a star. Inside a newborn star (Protostar) hydrogen atoms will be fused together to form helium. This provides the energy to power the star.

The Life After ignition, Main Sequence, is the longest stage in the life of a star, estimated at 10 billion years. Eventually, during the life of the star, the hydrogen will run out. At that point, it will begin to collapse in on itself, under its own weight. It again gets denser and hotter, until the point at which you can use the helium atoms for the fusion.

Expansion and deathAs the star fuses helium, it creates more energy, causing the outer layers of the sun to expand. Eventually, it will get so big, it will be classified as a Red Giant. As the star is getting so large, it loses hold of its atmosphere, due to the lowering force of gravity. The outer layers of the sun will drift so far away, it will become a planetary nebula.

White Dwarf and black dwarf

A white dwarf is the remnants of a burned out star. It is extremely dense, but there is no nuclear fusion going on. It is very, very hot, but will eventually cool down as time passes on. After enough time has passed, all of the leftover heat will dissipate, the white dwarf will become a black dwarf, making it much harder to find.

Red supergiantSome stars will Main Sequence stars. Are able to fuse elements further down on the Periodic Table, all the way to iron. Supergiants will burn much hotter than Main Sequence stars, and will die much younger. The star will get bigger and bigger, some even 1000 times the size of our sun. Once the sun starts fusing iron, there is no more energy to be achieved from fusion, and the star will collapse. It will start to bounce back, creating a huge supernova explosion.

Neutron starA Neutron star is what is left over after a supernova. It has a very small radius, but a very high density. The power from the supernova that birthed it gives the star an extremely quick rotation, causing it to spin several times in a second. Neutron stars can spin as fast as 43,000 times per minute, gradually slowing over time

Black holesA black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This will usually only happen with massive stars. Note: The theory of black holes is, well, a theory. It has not yet been proven.

Works consultedPictures:http://commons.wikimedia.org/wiki/File:Milkyway-galaxy-sky-stars_-_West_Virginia_-_ForestWander.jpghttps://sites.google.com/site/thelifeofastar101/our-sun/protostarhttp://funmozar.com/wp-content/uploads/2014/09/Space_star.jpghttp://www.paulandliz.org/Spitzer_Telescope/Default.htmhttps://prezi.com/jgjtnwr7mgz4/life-cycle-of-a-star-white-dwarf/http://www.nyugat.hu/tartalom/cikk/50737_hihetetlen_univerzum_2.reszhttp://xna.deviantart.com/art/Neutron-Star-187317350http://en.wikipedia.org/wiki/Black_holeWebsites:http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/stars/lifecyclestarsrev2.shtmlhttp://aspire.cosmic-ray.org/Labs/StarLife/starlife_main.html