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hello Spacelab i'm lawrence krauss director of the origins project at
Arizona State University a theoretical physicist and also the author of a
universe from nothing and I'm here today to answer the following question why is
there something rather than nothing well the question why is there something
rather nothing has been around as long as people have been asking questions and
it's gotten a lot of different answers first as a scientist I should say that
really why isn't a good question when we say why we really mean how because why
implies that there's some purpose and there may be no purpose to the universe
indeed as far as we can tell from all the evidence there's no evidence of
purpose so when you say why does something happen you really mean how
does it happen so the question is how does something come from nothing it
seems to violate the laws of physics but in fact the answer is quite interesting
because it turns out the simplest answer may be that nothing is unstable it will
always produce something indeed once you combine quantum mechanics and relativity
empty space which apparently of course is nothing is not so simple it's
actually a boiling bubbling brew of virtual particles popping in and out of
existence in a time scale so short you can't see them and in fact if you wait
long enough and allow gravity to operate empty space will eventually start
producing particles and in fact therefore the answer to the question why
is there something rather nothing or how is there something rather nothing is
nothing is unstable you're guaranteed if you wait long enough to have something
and if you want to ask the question you'll always be in the places with
something so actually empty space can produce enough particles to account for
all hundred billion galaxies in all and 100 billion stars in each galaxy now you
might say well empty space isn't nothing but if quantum mechanics actually
applies to gravity that space and time themselves become quantum mechanical
variables and hold universes can pop into existence spaces and times and
matter and energy can pop into existence without violating any laws of physics in
fact the total energy of our universe may be zero
fact when we look out it looks like it is zero and that gives us good evidence
that perhaps it popped into existence from nothing because no energy to begin
with and zero total energy in the end because the positive energy associated
with the masses of elementary particles is countered by the negative energy of
gravity now the question is of course what happened before our universe came
into existence was there anything at all and the answer is we don't know a simple
answer is that the question about what happened before may not be a good
question because since space and timer are tied to the matter when space and
time pop into existence time itself pops into existence and therefore there may
have been no before the question may simply not be a good question so there
may have been no sense in which you can even ask what happened before our
universe began alternatively current ideas from physics suggest that perhaps
our universe may be one of potentially an infinite number of universes which
are popping into existence at various times or maybe universes being created
right now in other universes ending and if that's the case then it's possible
that the characteristics of our universe are precisely those that allowed us to
evolve so when we ask why does universe have the properties it does the answer
is simply well if it didn't we wouldn't be here to answer the question or ask
the question now I should say finally the question itself is really rather
arrogant because it assumes the universe will always have something in it but in
fact in the far future as far as we can tell all the galaxies we can now see are
moving away from us faster and faster and faster and that means eventually the
entire universe that we can now see will disappear when those galaxies are moving
away from us faster than light which is allowed in general relativity so in the
far future that made us be one galaxy in which we live and then the stars will
burn out and the universe become cold dark and empty and then the simple
answer to the question why is there something rather than nothing is just
wait there won't be for long thanks for the great question if you
have a question leave it in the comments below the question with the most likes
will be answered in the next round by another expert
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