black holes

Put your about me here!

Hi! this is the first blog I'm posting on this account this account is mostly for things I'm interested in like astrophysics

The first ever picture of a black hole captured in 2019 using The Event Horizon Telescope

WHAT ARE BLACK HOLES?

A black hole is a place in space where gravity pulls so much that even light or any electromagnetic wave cannot get out. Gravity is so strong that matter in a dying star gets squeezed into a small space, as light cannot cannot escape a black hole this means we cannot actually see a black directly so how do we know they exist? That's what I'm going to explain in this blog post(s), how black holes form? What is a singularity? What if black holes were dark energy/dark matter? To understand and answer all these questions we need to know how a star is formed...

HOW DO AVERAGE STARS FORM AND DIE?

To understand how black holes are formed you first need to know stars are created and their eventual death. In the universe gas, rocks and dust, which contain a lot of hydrogen, are pulled together by a gravitational force, turning into a dust cloud. Due the amount of gravity pulling these materials together the individual particles speed up in turn making this dust cloud more dense and concentrated if this dust cloud gains enough energy this turns into a protostar think of these as a star to be, the particles speed up and collide more and more. This process transfers energy from the gravitational to thermal energy (heat energy). If the protostar becomes hot enough to the point in which the nuclei of hydrogen collide and fuse together to form a helium nuclei (nuclear fission), this means a star has been born the process of hydrogen nuclei fusing to create helium nuclei is call 'main sequence' as this is the main stage of a stars life. Our sun right now is in main sequencing! This main sequence is what creates the radiation that stars emit. In stars around the same size as our sun (up too 1. 4 times the sun's mass) or smaller, when the hydrogen supply in the star starts to deplete is stars to swell into a red giants, they then 'shed' their outer layers, leaving behind a planetary nebulae and white dwarf, they will slowly fade into a black dwarf. However we have never seen a black dwarf before as for a white dwarf to then become a black dwarf it takes longer than our universe has ever lived.

HOW DO STARS BIGGER THAN THE SUN DIE?

Pretty much all stars in the universe start out the same way, however what makes a bigger star different than other stars are how they die. In my own opinion it way more interesting but that's just me. As bigger stars have more energy and mass instead of nuclear fission just stopping at helium, the helium nuclei continue to form heavier and heavier elements until iron. For a star to exist they needs to be an equilibrium between the gravitational pull trying to contract the star and the radiation emitting from the star trying to expand the star, when iron nuclei collide instead transferring more and more energy like the other elements they do not transfer more energy this forms a heavy core, however when the heavier and heavier elements form in the core of a star this messes with the equilibrium. This means the gravitational energy 'wins out' as there is no more radiation being produced, the gravity 'takes over' and implodes forming a supernova explosion. However in the biggest stars the gravitational energy is so great that the sun mass collapses on its self in a small volume of space. The velocity needed to escape the star increases until the point where not even the speed of light can escape it.