Jump to content
Sign in to follow this  
iNow

A Universe From Nothing

Recommended Posts

This is just a super cool talk, on many levels. I personally found it rather interesting, and wanted to share it having just watched it myself... The universe came from nothing.

 

 

Got an hour? Don't waste it. Watch this.

 

Lawrence Krauss gives a talk on our current picture of the universe, how it will end, and how it could have come from nothing. Krauss is the author of many bestselling books on Physics and Cosmology, including "The Physics of Star Trek."

 

 

Watch here -->

 

 

7ImvlS8PLIo

 

 

From the talk:

 

The universe must be flat.

 

<...>

 

It turns out, that in a flat universe the total energy of the universe is precisely zero...Because gravity can have negative energy. So, the negative energy of gravity balances out the positive energy of matter.

 

What’s so beautiful about a universe with total energy of zero?

 

Well, ONLY such a universe can begin from nothing… And
that
is remarkable… Because, the laws of physics allow a universe to begin from nothing. You don’t need a deity. You have nothing… zero total energy… and quantum fluctuations can produce a universe.

 

<…>

 

Right now, we know it to an accuracy of better than 1%. The universe IS flat. It has zero total energy, and it could have begun from nothing. … And, I’ve written this piece (and, of course, I got a lot of hate mail) saying that in my mind this answers that crazy question that religious people always keep throwing out… Which is:

 

“Why is there something rather than nothing?”

 

The answer is…
There had to be
. If you have “nothing” in quantum mechanics, you’ll always get something. It’s that simple. It doesn’t convince any of those people, but it’s true.

 

 

What are your thoughts?

Discuss.

 

 

We humans believe that everything that happens to us is special... and significant. And that... Carl Sagan wrote beautifully about that in Demon Haunted World... That is MUCH of the source of religion. Okay... Every event that happens is unusual and unexpected. <...> Everything that happens has small probability... but, it happens. <...> The thing that physics tells us about the universe is that it's big, rare events happen all the time (including life), and that doesn't mean it's special.

Share this post


Link to post
Share on other sites

thanks for the viddy.

what a great speaker.

frank zappa used to say "nothing is what i want" i used to think he was talking zen,now i wonder if he was talking cosmology.

well worth the hour i wasn't in my shop working.

EDIT:

almost forgot to ask my question:doh:

towards the end where he's talking about a "workbench" (uni)verse maybe being created in the l.h.c. he said something like "from the inside it would look like it (the 'verse') was expanding, and from the outside it would appear to shrink" not really a quote but close i think.

do you have any idea why this would be?

 

sorry if it's in there and i missed it:doh:

Edited by moth

Share this post


Link to post
Share on other sites

That was a wonderful talk. Thanks for sharing. :D "Everything that happens has [VERY] small probablity."

 

Yes Moth, near the end he said if a new universe began, from the outside it would appear to be as a black hole. Very interesting. Anyone care to explain? How massive a black hole?

 

Recently I posted that "nothing" is so improbable. All we can see is something. In a flat universe, with total energy of zero, something will always come from nothing, especially if something has infinite time and space to pop out of nothing.

Share this post


Link to post
Share on other sites
What are your thoughts? Discuss.

 

Old news. The universe could have arisen from a quantum fluctuation. That is one of the possibilities. It is also possible that the universe was created by a deity. Insufficient data to decide between those hypotheses (and others). Science remains agnostic.


Merged post follows:

Consecutive posts merged
Yes Moth, near the end he said if a new universe began, from the outside it would appear to be as a black hole. Very interesting. Anyone care to explain? How massive a black hole?

 

As massive as the content of the unviverse. :) Think about it. Right now the data indicates that the universe began as an infinitely dense, infinitely small volume. That is what a black hole is.

 

In a flat universe, with total energy of zero, something will always come from nothing, especially if something has infinite time and space to pop out of nothing.

 

But this happens in an existing spacetime. And the "something" only lasts for a very small fraction of a second. What we have with the universe is not only matter/energy but spacetime as well. Not to mention being around for 13.4 billion years. So you also need spacetime to be a quantum event. So far, none of the standard physics theories have that. Spacetime cannot arise by quantum fluctuation in any the currently accepted theories. One of the attractions of String Theory (despite its multiple problems) is that spacetime can itself arise by quantum fluctuation.

Share this post


Link to post
Share on other sites

It actually doesn't answer the question of "why something rather than nothing." It (I guess) answers the question, "given the laws of physics, why is there stuff?" The former question is philosophical in nature and, I think, not one to which a direct and meaningful answer can be given. Arguably, the question itself is meaningless.

Share this post


Link to post
Share on other sites

i got the impression he was saying a flat universe means no energy was needed for it's creation and, i'm guessing, if you could somehow account for all the energy in the universe and add it all together it would still equal nothing?

 

edit:

 

i'm having trouble putting this in words but i think something along the lines of the difference between power and energy when time is factored in some things with a lot of energy have a little power.

or maybe my insomnia is just messing my head

Edited by moth

Share this post


Link to post
Share on other sites

Well, we know the universe has zero total energy... and, yet... we have such amazing stars and galaxies and (at least here on Earth) life. The idea is that something comes from nothing all the time. That in itself is rather interesting.

Share this post


Link to post
Share on other sites

from a conservation of energy standpoint, could that mean the law needs a corollary like energy can't be created except when a universe is created? or maybe the universe is not a closed system? or the creation of the universe transformed energy into some form that can't be recombined untill enough time has elapsed?

i prefer the last, but i'm still running on very little sleep. just enough to remember (any non-zero value)/eternity <>0 so the power idea from my last post won't work.

Edited by moth

Share this post


Link to post
Share on other sites

Can something come from nothing? What exactly IS "nothing"? I don't believe "nothing" is as simple as the word makes it sound.

Share this post


Link to post
Share on other sites

As defined in the talk, zero total energy.

Share this post


Link to post
Share on other sites

Dam...why are all your videos an hour long...:D

 

Is this accessible to those inexperienced with modern comsology and theoretical physics? If so, I may have to take time out and watch it.

Share this post


Link to post
Share on other sites

Yes. I'm rather inexperienced with modern cosmology and theoretical physics and I got a lot out of it. He also was presenting to a biology oriented audience, and they too are not cosmology or physics experts (in sum, the talk was tailored to a lay audience like you and me).

Share this post


Link to post
Share on other sites

The word "nothing" is too extreme for my comfort. He used the term rhetorically. He should have said that something can come from "zero total energy". Or at least he should have explained in advance what he meant by "nothing". Scientists are supposed to be precise. Nothing is an absolute term, and I don't believe it ever existed.

 

I am also a novice at cosmology, but I got a lot from his talk. Maybe because he said things like "something always comes from nothing". Hehehe.

Edited by Airbrush

Share this post


Link to post
Share on other sites

Wonderful talk.

 

But, right around 51:50, when he starts talking about how "Cosmology will end" in the future, and other advanced civilizations will develop a "false" picture of how the universe looks, how do we know that this isn't already happening to us? How do we know that our picture is the true picture of the universe?

Share this post


Link to post
Share on other sites
How do we know that our picture is the true picture of the universe?

 

We don't. We only have models which seem to describe the universe. Once we realize those models fail or are inaccurate, we try to find out where they were lacking and find a better description to replace or supplement them. :)

Share this post


Link to post
Share on other sites

I agree with Sisyphus, but would restate HIS restatement of the question as, "Given natural law, HOW does stuff emerge from the void?" The 'why' word is Rod Serling's 'signpost up ahead' that you are about to enter The Twilight Zone!

Share this post


Link to post
Share on other sites
I agree with Sisyphus, but would restate HIS restatement of the question as, "Given natural law, HOW does stuff emerge from the void?" The 'why' word is Rod Serling's 'signpost up ahead' that you are about to enter The Twilight Zone!

 

you are assuming that there is/was a void.

Share this post


Link to post
Share on other sites

I get funny feelings when a physicist makes statements like this, something along the lines of time travel is or is not possible. I want more tangible proof that exists outside of a document. Not to say the guy is right or wrong or some shade of gray on the issue, just that such a statement is really rather profound I would imagine.

 

What would our view of the universe be if we had people viewing the universe from all over the place, as far away from earth as you can get, would something that simple change our current views. How do we empirically know?

 

Another thing is energy levels. Now I know in particle accelerators more juice is supposed to produce different interactions or even new physics. How can anyone really estimate what the universe would look like if it the size of a pea? Would that be something beyond a black hole, as a BH does not seem to occur from every star going nova, and mass I think relates to energy right. So would it be a somewhat safe speculation that maybe some other form of matter could occur if we are dealing with so much mass, like the universe in total, would that be just a black hole, and why would it just be a BH and not something else, is that an effect of spacetime, or QM, or etc?

 

I just don't see this as an end all by any means. I also do not think we can currently state how much and of what makes up the current universe in order to perform such a calculation. Last time I checked dark stuff was still a mystery meat, unless I missed something and we know exactly to to a good enough extent of how much dark mystery stuff exists.

 

:)

Share this post


Link to post
Share on other sites
I get funny feelings when a physicist makes statements like this, something along the lines of time travel is or is not possible. I want more tangible proof that exists outside of a document. Not to say the guy is right or wrong or some shade of gray on the issue, just that such a statement is really rather profound I would imagine.

 

What would our view of the universe be if we had people viewing the universe from all over the place, as far away from earth as you can get, would something that simple change our current views. How do we empirically know?

 

Another thing is energy levels. Now I know in particle accelerators more juice is supposed to produce different interactions or even new physics. How can anyone really estimate what the universe would look like if it the size of a pea? Would that be something beyond a black hole, as a BH does not seem to occur from every star going nova, and mass I think relates to energy right. So would it be a somewhat safe speculation that maybe some other form of matter could occur if we are dealing with so much mass, like the universe in total, would that be just a black hole, and why would it just be a BH and not something else, is that an effect of spacetime, or QM, or etc?

 

I just don't see this as an end all by any means. I also do not think we can currently state how much and of what makes up the current universe in order to perform such a calculation. Last time I checked dark stuff was still a mystery meat, unless I missed something and we know exactly to to a good enough extent of how much dark mystery stuff exists.

 

:)

 

Lol the last time i checked the dark stuff it was mystery meat too mmmmm mystery meat. Sorry that statement just made me laugh, thanks :). lol

Share this post


Link to post
Share on other sites
The word "nothing" is too extreme for my comfort. He used the term rhetorically. He should have said that something can come from "zero total energy". Or at least he should have explained in advance what he meant by "nothing". Scientists are supposed to be precise. Nothing is an absolute term, and I don't believe it ever existed.

 

In terms of cosmology, "nothing" means no space, no time, no matter, no energy. IOW, the constituents of our universe.


Merged post follows:

Consecutive posts merged
i got the impression he was saying a flat universe means no energy was needed for it's creation and, i'm guessing, if you could somehow account for all the energy in the universe and add it all together it would still equal nothing?

 

The NET energy of the universe = 0. That is, the positive energy of matter/energy = the "negative" energy of gravitation. At least, this was the case before the discovery of "dark energy" -- the accelerating expansion of the universe.

 

In quantum mechanics, energy can be "borrowed" from the vacuum and particles come into existence for a very short time. The energy is then "paid back" and the particles disappear. It has been thought for at least 17 years (I read it in Paul Davies' The Matter Myth published in 1992) that the entire universe could be a quantum fluctuation and that the 13.4 billion age was just a "very short time" in this particular quantum field.

 

The problem has always been that a vacuum is in an existing spacetime. We don't see "something from nothing" or have the mathematics to get "something from nothing" in the absence of a spacetime. So, how do you get a spacetime from nothing?

Share this post


Link to post
Share on other sites
The problem has always been that a vacuum is in an existing spacetime. We don't see "something from nothing" or have the mathematics to get "something from nothing" in the absence of a spacetime. So, how do you get a spacetime from nothing?

I think you are making the common mistake of assuming spacetime to be some sort of tangible substance. It's not. It's just a word we use to help aid our understanding... essentially a manifold which we can use in our calculations when we are mathematically modeling the universe, but it is not something which itself has any physical or temporal properties. For that reason, I find the argument you've just put forth to be lacking. In order for your assertion to hold, spacetime would have to be something tangible, and it's not.

Share this post


Link to post
Share on other sites

How about space-time is a seething expanse of virtual particles popping in and out of existence constantly? Is it correct to say that except for the occasional hydrogen atoms in otherwise empty space, space-time is nothing?

Share this post


Link to post
Share on other sites

can spacetime be divided? is the inside of a black hole (or outside the observable universe) seperate from the outside of the black hole(inside of observable universe)?

can you divide nothing?

the more i think about this video the more my brain hurts.

Share this post


Link to post
Share on other sites

Hi, I was having a disscussion about this recently, I just began thinking about it again, and read up about vacuum energy on wiki http://en.wikipedia.org/wiki/Vacuum_energy.

 

I didnt watch the video and havent read all the posts in this thread, I was actually going to post a new one, but decided I'd jump in here instead of doubling up.

 

So to my questions:

 

I found it interesting it says in the original, gravity can have negative energy, does this mean attractive gravity, or is it talking about dark energy?

 

What is stopping universes from spontaneously appearing inside our universe then, would these appear as black holes?

 

What is stopping matter from continuously coming into existence (and staying that way) and negative energy increasing simultaneously? Are these truely balanced? (under assumption by negative energy gravity it means dark energy) Gravity has an inverse square rule (atleast simplified newtonian), does dark energy have the same rule?

 

IF dark energy isn't bound by the inverse square rule, AND matter in constantly coming into being along with dark energy, would this account for the apparent acceleration of the expansion of the universe?

 

Just fyi, I prefer the thought the universe always existed, since this also removes the need for a deity and since time is dependant on the existence of something.

 

__

sorry, I read it now, gravity is negative energy, still this doesn't explain what dark energy is.....

 

perhaps like particle/anti particle, also anti-gravity/gravity?? And particle/gravity, anti gravity/anti particle?

 

So dark energy increases as anti particles come into existence, annihilate with matter ---> more photons + more dark energy?

 

bah, just ignore me, somethings wrong here, somethings very wrong with the whole story - explain the imbalance in matter/anti matter, explain dark energy.

 

For an anti paricle to be truely anti, shouldn't it have negative mass?

Edited by Sorcerer
confusing myself.

Share this post


Link to post
Share on other sites
bah, just ignore me

 

That went without saying. :)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.