Stellar Evolution
Storyboard Text
- In Stellar Evolution, there is a lot we know about in the year of 2021 but haven't seen. Today CJ and I will be taking a journey exploring the stars and it's phases. We'll talk about light years and what they are. Also, one of the most amazing things, blackholes.
- Yes, all stars begin as a Nebula. A cloud of dust and gas that is dark. Explosions from a nearby star causes compression waves to move through the Nebula. Due to the gravitational pull, compression waves cause the Nebula to spin and twist. We call this gravitational collapse.
- First off, what is Stellar Evolution? Well it is the cycle of a star and how it changes. Stars are born and they die, but note this, stars aren't actually alive.
- Main Sequence Stars undergo Hydrogen Fusion. Our sun is a main sequence star. These stars are referred to as "normal stars". The give off radiant energy in the EM Spectrum.
- Hydrogen Fusion begins at 18,000,032 degrees Fahrenheit.
- Now, the nebula spins, it becomes warmer and warmer until it is now a protostar. This is the second phase of Stellar Evolution. However, it takes millions of years for a nebula to become a protostar.
- Depending on the mass of the protostar, it will determine which evolutionary path it takes. Eventually, the protostar will continue to get hotter as it collapses closer to the center, and it will become a main sequence star.
- (Normal Phase)
- Giant stars are 1-3 times bigger than out sun. The fusion in the core will continue causing helium atoms to fuse into carbon and oxygen as long as there's energy. Super Giant stars have 3-10 times the mass of our sun. The fusion will continue as well and will fuse into heavy atoms eventually ending at iron.
- The star will eventually run out of hydrogen atoms, and become a giant or super giant star. Smaller protostars create less massive sequence stars, thus becoming giant stars. Bigger protostars become super giant stars.
- Without any energy left, the core begins to collapse under its own gravity.
- For our sun to Nova, it will take about 4.5 billion years. Nova is when the nuclear fission in a star stops, and explodes in a burst of light and energy. The outer gases will drift away, forming a planetary nebula that forms around a sunlike star that is dying.
- The remains of mass collapses inwards, until all we have left is a hot dense core or matter called a white dwarf. They are about the size of the earth and shine for billions of years before they cool completely.
- Energy released in a Supernova can surpass the energy that the star radiated during its entire life.
- A supernova is energy released to the outer layers of the star. Supernova is an explosion that sends compression waves through space.
- A blackhole is a region of spacetime with gravity so strong, not even light is capable of escaping it. We cannot take pictures of blackholes because of how strong the gravity is and how many light years it would take to get there.
- The compressed core becomes a neutron star that weighs tons. It emits incredible amounts of energy and rotates very rapidly. A pulsar is a neutron star that emits a beam of radio waves. Lastly, if the core of a supergiant star contains more than 3x the sun's mass, the star goes farther into and under a gravitational collapse. A blackhole is caused when the force of the contraction causes a dense core.
- Light years are used to measure how far it would take light to travel in a year and are used to figure out how far stars and planets are away from us. Since light is the fastest known thing to man, we use light years since they travel the fastest.
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