black holes are the most powerful and extreme things in the universe and they're wildly weird and complicated what would happen if you fell inside one and what are they [Music] really first we need to talk about space and time space and time are the grand stage where the play of the universe unfolds but space isn't a fixed stage and time doesn't tick the same for everyone everywhere in short they're relative matter bends space and bent space tells matter how to move put some stars and planets on the stage and it sacks underneath them that misshapen
stage with all its little warps and dips gives us gravity black holes do not just bend the stage they're like trap doors places with so much mass that the Universe formed a noggo Zone where the rules change most black holes form when very massive stars die we explained this process in detail in our neutron star video all you need to know now is that in the final moments of really massive stars their insides implode at nearly a quarter of the speed of light this packs so much mass so close together creating something so dense that
it's sort of breaks the stage of the universe a black hole with 10 times the mass of the Sun would be barely 60 km across if you look directly at a black hole it looks like nothing the space under their control is blocked by an invisible oneway border called The Event Horizon The Event Horizon forms a shell around a region of space that once entered is shielded from the rest of the universe forever because the black hole trapo form space so much not even light can escape it and with nothing escaping to transfer information from
the inside it's impossible to tell what it really looks like we can still observe black holes because of their effect on matter things can orbit black holes just as they can orbit the Sun or a planet many black holes have discs of matter orbiting outside the Event Horizon this matter can become incredibly hot as close orbits can speed this matter up to half the speed of light and tiny amounts of friction and collisions between particles heat them to a billion deg making the space around these black holes ironically incredibly bright what would happen if you
were to try to get close or even inside a black hole first of all you'd see the strangest funhouse mirror in the universe mattera isn't the only thing orbiting a black hole gravity is so strong near them that light can orbit too if you hover just outside the event vent Horizon at the photon sphere in any direction you just see yourself Straight Ahead would be the back of your own head as light from your back travels around the black hole to your eyes gravity also Alters the passage of time itself the stronger the gravity the
slower time passes while you watch the universe above you speed up those far away will watch you in slow motion if you chose to fly away from the black hole you might find that eons have passed for the rest of the universe a freakish one-way time travel trip to the Future where your loved ones are long dead but getting close to a black hole can be incredibly dangerous a painful death by spaghettification awaits you because your feet are closer to the black hole than your head they feel a stronger pull of gravity enough to pull
you apart as you descend it gets worse the pulling gets stronger your body squeezed thinner and straighter until you've been reduced to a thin stream of hot plasma gobbled up in one final slurp never to be seen again spaghettification is only a risk with smaller black holes since they have much smaller radi ey if you go to the center of a galaxy and find a super massive black hole you might be able to experience crossing the Event Horizon as you approach The Event Horizon a distant Observer would think they never saw you enter it seeing
you stop and fade the last Light you emit trickling up and out away from the event vent Horizon meanwhile from your perspective the void of the black hole Rises up to meet you as lights from fewer directions can reach you the Blackness envelops you until your only view of the universe you left is a tiny spot of light here inside the Event Horizon space and time are so horribly broken the real time travel is possible so it's probably a good thing that nothing gets out if anything could Escape it could create all sorts of time
travel paradoxes and issues that break the universe as scary as the Event Horizon is it keeps us safe from that drama whether you have survived this long doesn't really matter as now there's only the certainty of crushing death in your near future inside the Event Horizon SpaceTime itself is so bent and warped that whatever Direction you move here every forward you go leads only towards the center of the black hole trying to go in any direction only brings you to the center faster to survive the longest you must do nothing in the center of the
black hole we find the singularity a single point with all the matter that has ever crossed the Event Horizon all crushed to a point infinitely small there is no memory of the things that made it as stuff disappears down the black hole trapo Forever The Singularity makes all things equal this actually breaks the universe in really cool ways we've made a video about this problem if you want to learn more but in a nutshell everything that comes too close becomes black hole matter concentrated at the singularity this lack of a memory of its past means
that a black hole has only three properties its mass Spin and electric charge everything else is lost they're a lot like fundamental particles in that respect this actually means that every single black hole in the universe is the same sure their mass is different and some spin faster than others but if we were to put all the singularities into a magical physics Museum they'd be identical like electrons but just like fundamental particles the properties of singularities are the best ways we can describe them on paper rather than an accurate representation of reality our current theories
about the universe namely general relativity are just not able to describe or explain them the curvature of space becomes infinite density becomes infinite and our rules just don't make sense The Singularity has no surface or size something like a divide by Z era in the universe so singularities might not even exist or be completely different things but this is all we know right now from the best prediction we have from our best current theory of SpaceTime also basically everything you've ever heard about black holes even in this video is about theoretical black holes that aren't
spinning because their maths is so much much easier but since black holes were born from dying stars that were spinning extremely quickly in their final moments as far as we know all black holes in the universe should be spinning right now at incredible speeds too up to 90% of the speed of light this means that in reality black holes are even more screwed up than they usually get credit for the singularities of rotating black holes are even Wilder the rotation causes them to swell outwards into a sort of ring this rotation is so powerful that
space itself is dragged along this creates another region around spinning black holes called the ergosphere where it's impossible to stay still no matter how hard you try like a rushing Whirlpool of SpaceTime The Tide Is irresistible and the black hole makes you orbited whether you want to or not okay so what will happen to black holes as the universe ages and dies around them again we don't know but we have some ideas based on our current understanding of physics Hawking radiation in Quantum field Theory the vacuum of space is boiling with Quantum fluctuations these fluctuations
are creating matter and antimatter pairs of particles from nothing which only exist for a very short time before annihilating when this happens near the Event Horizon of a black hole one of these particles can fall in stopping them from annihilating the escaping particle is hawking radiation ultimately the mass of this particle must come from the black hole so over eons black holes will shrink and radiate away Hawking radiation is not the stuff that fell into the black hole it's new stuff stealing Mass from it as the black hole shrinks the Hawking radiation gets stronger faster
and faster until what's left eventually evaporates in a flash of high energy radiation like a nuclear bomb and then nothing but that won't happen for a long long time a black hole with the mass of our sun has a lifetime of 10 to the power of 67 years which means that it would take 10,000 billion billion billion billion billion billion years to lose 0.00001% of its mass but most black holes are way more massive than our sun the most massive super massive black holes in the centers of galaxy have lifetimes of 10 to the power
of 100 years how long is that imagine an hourglass filled with one grain of sand for every single particle in the universe every 10 billion years one single grain of sand falls to the bottom if we waited for all the sand to fall down not even 1% of the lifetimes of these black holes would have passed there is no good concept to help our brains grasp these time scales will we ever truly understand black holes really know what's going on inside them no one knows we can only see their outsides and the theories we have
probably get their insides wrong but it's okay to not know everything it just means there's still work to be done it means there are still Mysteries to solve and Big Ideas to think about which is why humans do science in the end we can at least be sure that we still have plenty of time left to think about them before the last one melts away if you want to continue thinking about black holes you can do so by getting one of the many black hole related things the ksun team has made with love like our
black hole infographic poster that teaches you all the black hole Basics or our choose your own black hole Adventure poster that takes you on a spectacular ride and might leave you in need of a cuddle in in which case we've made a black hole and White Hole plushy and if that's still not enough we've also just released super comfy space socks very shiny space pins a new tote bag and pouch set and we have many other great space related products that are all designed with love and care by us here at ktz gazar getting something
from our shop is the best way of supporting ktz gazar while getting something beautiful in return because of you we can keep making elaborate videos like the one you just watched and release them for free free for everyone thank you so much for your support [Music]
