Say goodbye to reality as you think you know it
what you are about to learn will make you question the universe around you and if you even exist
do you really believe you see what you see and know what you know think again welcome
the Factnomenal in today's video we peel back the layers of reality and call into question our place
in the universe and what you assume you know about space and time prepare for sleepless nights as
you sort through these mind-bending paradoxes is there only us our universe is full of life right
after all it's many billions of years old the solar system is relatively young and
astronomy tells us there are at least 100 billion planets in our milky way and how many times does
hollywood show us the arrival of supermassive spacecraft bringing doom and gloom to all of us
so where are they Nobel Prize winning physicist Enrico Fermi asked this question in a casual lunch
conversation in 1950 and fermi's paradox has puzzled scientists ever since seti the search
for extraterrestrial intelligence institute in California explains that fermi theorized a
civilization with rocket technology and motivation could quickly colonize the entire galaxy within
a few tens of millions of years every star system could be brought under the wing of empire
tens of millions of years may sound like a long project but in fact it's quite short compared to
the age of the galaxy which is roughly a thousand times more so where are they some astronomers use
the drake equation which combines the number of stars hospitable to life-sustaining planets
with other variables that lead to civilizations transmitting signals across the milky way
as for the results anywhere from one us to several million in the milky way alone and remember some
civilization must be the first one could that be us as science fiction icon Arthur C Clarke
famously proclaimed either we are all alone in the universe or we are not both are equally terrifying
a new meaning to being in the loop hand in hand with this puzzle is the bootstrap paradox
named after a Robert A Heinlein time travel story a future event causes a past event
which leads to that future event got it in the terminator movies the conscious ai
global system of the future and instigator of humanity's downfall Skynet could not exist without
leftover components of the t-800 cybernetic organism who we know is Arnold Schwarzenegger
send back to terminate John Connor its technology is reverse engineered and Skynet and cyborgs
and a long series of paradoxes were born as a result an object or piece of information gets
trapped in an infinite cause and effect loop in other words where is the point of origin
back to the future can we travel through time besides the universal tick tock way each of
us does every day Einstein's theory of special relativity says yes at least in one direction
the genius himself once said people like us who believe in physics know that the distinction
between past present and future is only a stubbornly persistent illusion say hello to the
mind-blowing grandfather paradox one travels back in time say 200 years and murders their many times
great grandfather this of course means generations of other ancestors never came to be does this
prevent the time traveler's existence and in that case how would this relativist a killer have
traveled back in the first place if their birth was already erased time to reach for the aspirin
"quoth the raven nevermore" imagine you are standing in a small grove of trees looking
outwards and you can see glimpses of sky from beyond the tree trunks
however in the middle of a great forest your sight is only of a solid wall of tree trunks combining
the near and distant in your vision shouldn't the universe be the same after all when we gaze into
the three-dimensional cosmos we are looking into septillions of stars and even though they are at
varying distances wouldn't they all have light reaching us creating a brilliant wall in the sky
instead the night sky is almost black not bright red or glaring white hot this Olbers paradox
was first posed in 1610 by Johannes Kepler who suggested the universe only extends out so far
thus the empty space and darkness but it wasn't an astronomer who first hit on the truth or what we
think is the truth it was a poet of all things in 1848 American gothic poet and writer Edgar
Allan poe surmised the universe is simply not old enough to fill the sky with light
not enough time for starlight from every corner of space to reach us
building on poe's idea astronomers conclude that yes while there may be an infinite number
of stars beyond the cosmic horizon of the 13 plus billion year old universe that would keep
us bathed in light every night there are too few observable stars to completely light up the sky
so a poet stumbled across the likely answer maybe we should dig up Shakespeare and ask him
about fermi or inflation theory or black holes speaking of digging folks up a lovely variation
of the aforementioned grandfather paradox is the classic why don't we go back in time and
terminate hitler paradox or maybe some middle school bully but let's stick with hitler for now
it's such a popular idea that the phrase everyone kills hitler on their first trip has become a meme
so how about jumping into a Delorean or blue police box and doing humanity a giant favor
not so fast if you transport back and whack baby hitler you've now created a world where hitler
never rises to power and world war ii does not happen that's a good thing right yes but in the
process you've removed the future motivation to transport back and whack baby hitler so
another paradox and of course there's always the possibility that by interfering with the previous
course of history you may unleash something worse in hitler's case that's highly unlikely right
when is a black hole not a black hole Einstein's general theory of relativity says a black hole's
gravitation is so intense that nothing can escape it now let's define information for the physicist
information is the specific state of every particle in the universe every little detail
and the first law of thermodynamics says matter and energy cannot be created or destroyed
and the sum total of matter and energy in the universe is a constant well what happens to
matter information consumed by black holes that is the black hole information paradox
if there's ever a bright blinking light to remind us just how little we really understand
about the universe this might be it in 1975 physicist stephen hawking theorized black
holes in time will evaporate away and release their mass and energy back into the cosmos
cosmologists believe the quantum information for everything that went into the black hole
was preserved on its surface even as the matter was doomed so where does that information go when
the black hole evaporates where did that bottle of aspirin go mind officially blown
paradoxes may have no solution or be only explainable by theoretical propositions
that can never be subjected to the scientific method perhaps time travel is forever relegated
to science fiction and aliens only exist in Hollywood as physicist Stephen Hawking said
the best evidence we have that time travel is not possible and never will be is that we have
not been invaded by hordes of tourists from the future after all wouldn't a future bill and ted
have come here from 1,000 years down the road by now for another excellent adventure so what
do you think about these sleepless night-inducing paradoxes will there always be mysteries that are
simply unsolvable tell us in the comments and as always thank you for watching Factnomenal