[Music] welcome back to science click today let's Embark together on a visual journey through space and time we are in Intergalactic space billions of billions of kilometers from Earth we are lost between two neighboring galaxies our own the Milky Way and Andromeda another galaxy also made up of hundreds of billions of stars around us space is almost perfectly empty for all this we are not nowhere a web is woven around us it is the web of the universe itself SpaceTime this imaginary grid made up of a multitude of small particles will allow us to visualize
the invisible the geometry of the universe and to understand its Dynamics from where we are the grid is calm motionless nothing disturbs it and if we throw a marble it zooms straight forward moving away through the void forever in reality the grid is not perfectly static if we fast forward we see that it drifts very slightly like a river which flows into the stars and whose current carries everything with it the Stars clouds of gas and dark matter effectively distort SpaceTime pulling the fabric of the universe in their Direction very slowly the two galaxies are
getting closer and in several billion years long after we disappear the Milky Way and Andromeda will eventually merge and become one while Andromeda is getting closer researchers discovered at the dawn of the 20th century that most galaxies actually move away as a whole the universe is constantly expanding like a fabric that stretches the grid swells more and more and Carries galaxies away from each other as this expansion progresses the wavelength of their light is stretched and turns red we know today that this expansion accelerates stimulated by still mysterious Dark Energy the expansion would have begun
13.8 billion years ago extremely compressed containing only a mush of fluctuating energy the universe would have descended suddenly to reach astronomical dimensions in a fraction of a second this is the Big Bang what was there before that no one really knows tiny fluctuations becoming gigantic would have attracted matter condensing it into filaments Halos then galaxies and stars today we live near one of these Stars the [Music] sun around the Sun revolved multiple bodies planets asteroids and comets moving freely in the grid of the universe the immense mass of the Sun curves SpaceTime and the fabric
of space Falls towards the star taking everything with it this is how the planets orbit without moving away from the Sun they move straight forward but the current continuously pulls them back towards the center to a lesser extent planets also attract the grid of the universe in their direction for instance the Earth holds the moon its natural satellite as well as all our artificial satellites the International Space Station zooms Straight Ahead through SpaceTime but SpaceTime is curved by the Earth and prevents it from moving away at a far away distance the grid flows slowly and
an object passing fast enough would have no difficulty escaping the pool but the closer we get to the center the denser the flow becomes and the more the grid accelerates on the surface of our planet Rockets must reach a very high speed to take off from the ground and escape the [Music] Earth the grid converges towards the center and if we drop several apples next to each other SpaceTime will bring them together in one Direction and stretch them apart in the other direction this is called tidal forces it is the same action that the moon
inflicts on the earth causing movements of the water on its surface the back and forth motion of the tides is caused by the Spin of the Earth on itself it rotates in approximately 24 hours this motion of all its mass affects SpaceTime and very slightly drags the grid along with its rotation when we drop an apple even if it does not touch the Earth the rotation of our planet influences it at a distance and slightly bends its trajectory and orientation inside the Earth the grid continues to fall downwards it seeks to draw everything towards the
center but the materials that make up our planet are resistant they exert enormous outward pressure so as not to collapse on themselves it is this pressure that we feel in our legs when we fall to the ground after a jump at the center the river converges and a marble if it could withstand the immense pressure of the Earth's core would remain there motionless arriving at the center all the particles that make up the grid continue ahead and rebound until they emerge back out from the earth if we could jump through the whole planet we would
come out on the other side in 5 billion years our star will eventually die the sun will no longer be able to generate its pressure and resist the flow of the grid its core will collapse on itself forming an extremely dense white dwarf while its atmosphere will slowly expand into a gigantic planetary nebula however not all stars disappear in this way a few hundred light years away another star a super giant is also burning its last fuel 20 times more massive than the sun its internal pressure can no longer Bear all its weight the heart
collapses and the outer layers bounce back exploding into a supernova the core compresses more and more until it forms a neutron star it contains the mass of two suns in a space just 30 km across the grid of the universe is pulled so hard that light itself is dragged along creating strange Optical distortions a few thousand light years away another star even more massive is about to explode in an instant the core is carried towards the center and the outer layers are violently blown away this time the universe is stronger it drags the core of
the star unable to resist towards the center where all the mass condenses within a small sphere the universe is so curved that its fabric Falls faster than light nothing can escape this hellish treadmill everything is carried downwards it is impossible to stay still or even send a signal outwards it's a black hole in the universe some black holes are born near another star and they capture its matter in the form of a very high temperature plasma entering an orbit around the black hole the plasma forms an accretion disc which loses energy and spirals towards the
horizon inside the black hole very close to the center the flow becomes infinitely fast and all objects are strongly torn apart the grid stretches so violently that it separates atoms from each other and spaghettify all B IES at the center our current theories do not yet adequately describe the quantum behavior of space time in the universe nothing is static All Stars more or less rotate on themselves when they die and their core compresses to form a black hole their rotation accelerates like an ice skater folding her arms alongside her body this rotation is imprinted in
the very fabric of SpaceTime which continues to rotate [Music] afterwards below a certain distance inside what we call the ergosphere of the black hole the entire grid is carried into a faster than light Vortex which drives bodies in the same direction of rotation even light is forced to rotate with the black hole below the Horizon where the grid Falls faster than light such such a black hole would have a second internal Horizon where the centrifugal force created by the rotation of SpaceTime counteracts gravity and slows down the fall of the grid mathematics extends these internal
horizons with white holes from which we could emerge to explore parallel universes however the inner Horizon of a black hole is extremely unstable and probably doesn't exist the structure at the center of a real black hole remains mostly mysterious finally if two black holes meet they can begin to dance pulling each other faster and faster until they merge and form an even bigger black hole this new black hole vibrates like a bubble and eventually stabilizes during such an event the entire fabric of the universe is driven by the vibration gravitational waves more powerful than all
observable stars form and Escape at the speed of light distorting everything in their path on September 14th 2015 after a journey of over a billion years one of these vibrations ended up crossing the Earth in the blink of an eye the Earth shook by a fraction of the size of an atom but for the first time in history researchers had detectors to measure these vibrations they bore witness to a cataclysmic Fusion that happened more than a billion years ago in 2015 a whole new field of astronomy thus opened up gravitational wave astronomy allowing us to
probe the very structure of the [Music] universe
