Is Nothing Something?
Most recent answer: 10/22/2007
- Draken-Korin (age 4)
The 'nothing' of space means what's left when all the removable stuff (atoms, etc.) is removed. So I guess the question could be whether the un-removable part still does something. Right now, it looks like it does. The expansion of the universe looks very much like it's accelerating, the way it would if space were filled with some un-removable energy density.
Is that something? Or is it just another choice of words to describe an acceleration which could just as well be taken as an independent law of nature, without saying that 'something' in space caused it?
There's very much evidence that the acceleration from the background of energy in space was once much larger. That means that it can't always be ascribed to some fixed law, and might best be thought of as due to somethingness of space.
Of course that raises another possibility. Could there someday be another change in that background? Could there someday be truly nothing in 'empty' space? We don't know.
Mike W.
There are other good indications that the vacuum plays an active role in physical processes that can be measured. All the elementary particles we know of have zero size (that is, particles whose sizes we have been able to measure have been found to be themselves made up of constituent pieces.
For the particles with "zero" size, we can ask what the space is like nearby these little points. It turns out that this space is seething with particles and antiparticles, popping into and out of existence (in particle-antiparticle pairs) according to the laws of quantum mechanics. These particle-antiparticle pairs do have a net observable effect on the strength of the electric field around a real particle. In each pair, the particle that's oppositely charged to the real particle is pulled inwards, towards the real particle, while the other half of the pair is repelled. This effect amounts to a "screening" of the charge of the real particle. We can tell that this is going on by asking what the strength of the electric field is very close to a particle, and finding that it is in fact bigger than might be expected if the vacuum were "empty". There are other observable effects, such as on how strong the magnetic field is around a spinning particle.
These measurements lead us to believe that these particle-antiparticle pairs are constantly being produced and destroyed everywhere, including in every bit of vacuum. You cannot remove them, so by the definition above, they are part of the vacuum.
Here's another interesting consequence of this: Nothing can escape from inside the event horizon of a block hole. However, particles and antiparticles are constantly being created and destroyed, even near the event horizon of a black hole. One of the pair can fall in, leaving the other half of the pair to fly away. This phenomenon is called "Hawking radiation," after Steven Hawking, who predicted it in the 1970's. Black holes, if they just sit in space with no real matter to fall in (that is, they are surrounded only by vacuum), will gradually "evaporate" because of all the Hawking radiation escaping.
Tom
(published on 10/22/2007)
Follow-Up #1: being and nothingness
- Michael Bolt (age 18)
Canada
Mike W.
(published on 07/27/2009)
Follow-Up #2: dark something
- Joshua (age 13)
kennesaw
The "dark energy" which is also much discussed is part of what might be meant by "the something that is nothing" or some such phrase. Dark energy seems to be, at least for the time being, an unremovable property of space.
Mike W.
(published on 08/19/2010)
Follow-Up #3: nothingness
- Anonymous
As for "before the Big Bang", many modern cosmological theories have a great deal going on before the Big Bang. For an interesting take on that, you might read Sean Carroll's "From Eternity to Here".
Mike W.
(published on 08/27/2010)
Follow-Up #4: universal nothing?
- Xiaogang (age 30)
Enschede, Netherlands
Mike W.
(published on 05/23/2011)
Follow-Up #5: something in empty space?
- Toy (age 17)
heshey PA USA
Thinking about it, I guess that saying that space "is something" (besides boosting its self-esteem) might suggest that someday a theory (string theory?) about that something might be developed. Then once the theory is developed, it could tell us something about what to expect to see. Based on pretty much pure guess, I'd the say that space is something. Or maybe not.
Mike W.
(published on 06/20/2011)
Follow-Up #6: the nothingness of philosophy
- Ray Robertson (age 15)
Rancho Cucamonga, CA, United States
Mike W.
(published on 08/28/2011)
Follow-Up #7: The Theory of Nothing
- Nick (age 65)
Daly City, CA
I'm not sure about the meaning of two parts of your question. What does "in theory" mean? Is that supposed to be a theory of our universe or a theory of some hypothetical mathematical construct? The question of what "in theory" means often comes up, because in science we mean some specific theory, but people often use the phrase without any particular theory in mind.
The second concerns "safely say that "perfect vacuum" is NOTHING". You can say that without personal danger, since you aren't in North Korea, but it may be too safe to say. That is, it's not clear that there's anything anybody could see that could possibly show it's wrong, so it's not clear that it means anything.
Mike W.
(published on 11/16/2013)
Follow-Up #8: space changing in time
- Allan (age 47)
London
Space obviously gets different properties if some stuff goes through it, but I think you're asking about some "empty" space. It does seem as though its properties can change. Space is currently inflating a bit, just as General Relativity would predict if space were filled with some sort of fixed energy density. It looks as if there was a brief period just after the Big Bang when space inflated very rapidly, as if it were filled with some much higher energy density. So it seems that the properties of space have changed over time.
You ask a very good question about what sort of evidence we could have for claims like this. One of the main pieces of evidence for the current weak inflation comes from the red-shift of the light of distant galaxies, which allows a sort of calibration of how the expansion of the universe has changed over time. Another piece of evidence about the same history comes from how stretched out the tiny ripples in the Cosmic Microwave Background are. The form of the ripples also gives evidence about the suspected early fast inflation. Details from the Planck satellite recently gave support to the idea of early fast inflation over the main alternative theory. More results are expected soon.
Mike W.
(published on 12/22/2013)
Follow-Up #9: does 0%=100%
- Calm Elder Kiwi (age 17)
Groom Lake
I can't make head nor tails of it.
Mike W.
(published on 06/18/2015)
Follow-Up #10: philosophy of nothing
- karma (age 53)
Denpasar Bali Indonesia
What you read was empty word-spinning, with no content. The sum of all the real numbers has no defined value. Even the sum of all the integers has no defined value- it depends on what order you add them in.
Then the conclusion about whether or not "nothing is something" tell us nothing at all about what to expect to observe in the world. There no way to tell if word combinations like that stand for true or false sentences. they're meaningless.
Mike W.
(published on 02/18/2017)
Follow-Up #11: 0$-->2$
- Tshepo (age 21)
Lobatse, Botswana
It would be great if money worked that way, adding a few zeros to get something. Unfortunately it doesn't, and neither do other quantities like mass or charge.
Mike W.
(published on 02/20/2018)