The Multiverse Hypothesis Explained by Neil deGrasse Tyson

you believe this is the only universe there's  not just one universe there's a multiverse we   think when i say we just the scientific community  physicists who concern themselves with the very   early universe cosmologists that the laws of  physics as we experience them are set in the   very earliest stages of the universe and quantum  fluctuations in everything would be responsible   for another universe having slightly different  laws of physics than ours because the quantum   fluctuations will taken in a slightly different  law of physics direction than our universe   and this would just keep going every universe  that's born even if it started out sort of   the same in the very first instant a later  instant when other laws of physics manifest   could be slightly different [Music] the  concept of infinite worlds is a very old idea   discussed in the philosophy of ancient  greek atomism which states that the   physical world is composed of fundamental  indivisible components known as atoms   ancient philosophers proposed that infinite  parallel worlds arose from the collision of atoms   in the 3rd century bc philosopher chrysippus  suggested that the world eternally expired and   regenerated effectively suggesting the existence  of multiple universes across time however the   concept of multiple universes has reached  maturity only in the time of modern physics   in dublin in 1952 erwin schrodinger gave a lecture  in which he warned his audience that what he was   about to say might seem lunatic he said that  when his equations seemed to describe several   different histories these were not alternatives  but all really happened simultaneously this   sort of duality is called superposition  which is a hard concept to grasp in and   of itself and understandably so our brains are not  evolutionarily equipped to intuitively understand   quantum mechanics and large-scale cosmic phenomena  but we'll give it a try anyway with the multiverse   where there could be pockets of the universe  that are expanding with no knowledge of any other   pockets of the universe these are essentially  independent universes from one another and never   the twain will meet imagine you're a ship at sea  and you look to the horizon and that's your whole   universe there to the horizon there's another ship  that has its own horizon and these ships don't   even see each other you'll only see each other  if somehow your two horizons can overlap and we   don't know how to do that in our universe because  they're non-causal you'd have to find some way to   tunnel from one universe to the other in order  to access that but that could be very dangerous   because if the laws of physics are different  than the ones you evolved on then you could   just dissolve into a pile of goo because the  charge on the electron is different and all of   your biochemistry would change the multiverse  is a hypothetical group of multiple universes   together these universes comprise everything that  exists the entirety of space time matter energy   information and the physical laws  and constants that describe them   the different universes within the multiverse are  called parallel universes alternate universes or   many worlds in pop culture they are known  as parallel dimensions quantum realities   alternate realities etc the physics community has  debated the various multiverse theories over time   prominent physicists are divided about whether  other universes exist outside of our own some   physicists say the multiverse is not a legitimate  topic of scientific inquiry concerns have been   raised about whether attempts to exempt the  multiverse from experimental verification   could erode public confidence in science and  ultimately damage the study of fundamental physics   some have argued that the multiverse is a  philosophical notion rather than a scientific   hypothesis because it cannot be empirically  falsified the ability to disprove a theory   by means of scientific experiment has always  been part of the accepted scientific method   nobel laureate steve weinberg suggested  that if the multiverse existed the hope   of finding a rational explanation for the  precise values of quark masses and other   constants of the standard model that we observe  in our big bang is doomed for their values   would be an accident of the particular  part of the multiverse in which we live   there could be a universe where the laws  of physics there will never allow matter   to coalesce you'll never get stars that would  be a lifeless universe there could be another   universe where you can make stars but you don't  make heavy elements that would be a universe with   stars beautiful night skies as we have now but  nothing that we know and love no planets no life some scientists analyzed the data from  the wilkinson microwave anisotropy probe   an uncrewed spacecraft operating from  2001 to 2010 that measured temperature   differences across the sky in cosmic microwave  background the radiant heat emitted from the   big bang and claimed they found evidence  suggesting that our universe collided with   other parallel universes in the distant past  however a more thorough data analysis from the   wilkinson microwave anisotropy probe and from the  planet satellite a space observatory operated by   the european space agency from 2009 to 2013  which mapped the anisotropies of the cosmic   microwave background did not find any statistical  significant evidence of universe collisions   there was no evidence of any gravitational  pull of other universes on ours either   and to add insult to injury to the proponents that  the multiverse hypothesis has been backed up by   statistical evidence the planck satellite has a  resolution three times higher than the wma probe   in the 1920s quantum mechanics was invented  discovered however you want to think scientific   advances take place quantum mechanics is the  study of the small how particles behave and we   learned that if you get to a small enough scale  you lose the ability to predict with precision   the behavior of the system you can only describe  it statistically and there are ranges of things   it can do and all you can describe is the range  of properties that it may have well here's this   big grand universe we have described by einstein's  general theory of relativity but at the big bang   the entire universe was the size of an atom and so  you have the need to have the physics of the small   quantum mechanics marry the physics of the large  general relativity because they're occupying the   same space now when you take quantum mechanics and  apply it to aspects of the fabric of space on that   scale what you have is a gurgling of the fabric of  space-time in fact it's been called a quantum foam   and so now when you look at this foam applying the  laws of quantum mechanics to it you realize that   this fabric is not limited to one zone or another  in fact there's a region of the fabric that could   hatch out an entire universe with a variations in  the laws of physics simply because the conditions   that would spawn the laws of physics had  variation in them and so the multiverse   is not just some invention out of the ether it  flows out of an application of quantum mechanics   to general relativity prominent scientists such  as max tegmark and brian greene have devised   classification schemes for the various theoretical  types of multiverses and universes that they might   compromise max tegmark has provided a taxonomy  of four levels of universe beyond the familiar   observable universe level one is an extension  of our universe a prediction of cosmic inflation   is the existence of an infinite ergotic universe  which being infinite must contain hubble volumes   realizing all initial conditions level 2 are  universes with different physical constants   in the internal inflation theory the multiverse or  space as a whole is stretching and will continue   doing so forever but some regions of space stop  stretching and form distinct bubbles that are   embryonic level 1 multiverses level 3 is the  many worlds interpretation of quantum mechanics   one aspect of quantum mechanics is that certain  observations cannot be predicted absolutely   instead there is a range of possible observations  each with a different probability according to the   mini world's interpretation each of these possible  observations corresponds to a different universe   level 4 is an ultimate ensemble the ultimate  mathematical universe hypothesis is tegmark's   own hypothesis this level considers all universes  to be equally real which can be described by   different mathematical structures tegmark remarks  that abstract mathematics is so general that   any theory of everything which is definable in  purely formal terms independent of vague human   terminology is also a mathematical structure he  argues this implies that any conceivable parallel   universe theory can be described at level four and  subsumes all other ensembles therefore this level   brings closure to the hierarchy of multiverses  and there cannot be a level 5. the american   theoretical physicist brian greene discussed  nine types of multiverses but we will discuss   them in another video enough head scratching for  today thanks for watching did you like this video   then show your support by liking subscribing and  ringing the bell to never miss videos like this [Music]   you

Channel: Science Time

Views: 5,684,860

Keywords: multiverse, neil tyson, Neil deGrasse Tyson, neil tyson multiverse, universe, parallell universe, multiverse hypothesis, space, alternate reality, neil degrasse tyson multiverse, multiverse theory, infinite universe, science, science time

Id: h6OoaNPSZeM

Length: 10min 2sec (602 seconds)

Published: Sat Nov 28 2020