How do they form?

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Some Words

A star, once fusion has begun, is essentially a balancing act. Gravitational forces want the star to collapse. But it is these very forces that cause the compression and heating necessary for fusion to occur. We know that hot objects expand, and it’s this expansion that pushes back against the force of gravitational collapse.

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As a star gets older, it’s supply of hydrogen for fusion fuel is depleted. With less fusion comes less push outwards, so the arrow of gravitational collapse begins to win. It shrinks. But, as said earlier, it’s this collapse that provides the energy to kick off fusion. If the star is massive enough, another round of fusion, but with helium as fuel, is kicked off. A grand video by NASA is located below, and fast forwards our explanation immensely.

(PLEASE SEE “BLACK HOLES IMAGE RESOURCES” PAGE FOR VIDEO SOURCE)

For the discussion of black holes, we will only talk about stars more massive than Sol, our sun. For stars like these, gravitational collapse continues when the core becomes predominately iron. As you saw in the video, energy is lost when we try to fuse iron. Some very interesting things occur as the star continues to collapse. The elements in the core are stripped apart into their base components: electrons, neutrons, and protons.

Some very strange quantum mechanical effects occur, which arise to the star’s death. In a giant explosion, the mass of the core fuses into elements heavier than iron, and the star is blasted apart. A fun animation of this can be found below:

(PLEASE SEE “BLACK HOLES IMAGE RESOURCES” PAGE FOR VIDEO SOURCE)

Sometimes there is a remnant of the core, comprised of neutrons, which continues life as a neutron star. But other times, the remnant keeps collapsing until it goes beyond it’s Schwarzschild radius and becomes a black hole.


SUCH A DENSE OBJECT MUST HAVE SOME STRANGE AFFECTS ON SPACE-TIME! CLICK THE LINK BELOW TO SEE SOME EXCITING SCIENCE!

Gravitational Waves