Outside the universe

What is outside the universe?

A colleague asked me this question on Friday. Good to see college leaders take the time to ponder the important questions.

The stock answer is nothing – or rather, there is no outside, simply because the technical meaning of the word ‘universe’ is  all of matter, energy, space and time. So ‘outside the universe’ is a bit of an oxymoron – like asking what is north of the north pole, or what happened before the beginning of the universe.

It’s an important question and at the root of many misconceptions in cosmology. Consider for example the expansion of the universe. There is very strong evidence that our universe is expanding (see post on Hubble graph). However, this expansion is not really like the expanding balloon so beloved of science writers, because the universe is not expanding into space in the manner of a balloon inflating in a room. Instead it is space itself that is expanding (really spacetime). This is also why the theory of cosmic inflation can posit an exponential expansion of the universe (many times faster than the speed of light) in the first fraction of a second, without contradicting relativity (which forbids travel faster than the speed of light in space).

That said, the question has got more complicated recently. If inflation is right, it seems we have to accept the possibility that a great many universes may have been spawned in the first fractions of an instant – the multiverse. Hence might one ask about ‘outside a particular universe’? I think this is essentially the same question, except it is now ‘what is outside the mulitverse?’. A question which has the same answer, which is nothing .Or better, there is no outside. We think. So far.

Artist’s impression of the mulitverse


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19 responses to “Outside the universe

  1. Have you considered, when asked questions like that, just saying “cotton candy” and grinning like a lunatic? The results might be interesting!

  2. cormac

    Hey Seth, hope things are well at CERN.
    I have no doubt the answer is ‘cotton candy’ but i was keeping it a secret for now.

  3. James

    I am somewhat suprised that the Waterford Institute, when teaching cosmology to adults, should on the one hand critisise others for their “stock answers” to fundamental questions, and on the other just proceed to trot them out themselves.

    You might as well just get out that trampoline, medicine ball, and grapefuit, and display GR in its full glory.

    Perhaps less of the spin and more of the spinors :-)

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  5. cormac

    Easy James – I mean ‘stock’ answer in the sense of the standard answer. This does not imply that it is wrong, it implies that it is the best answer we have.
    That said, cosmologists the world over (real ones, not just teachers) are now keeping an open mind due to the recent evidence for inflation, and the implications of inflation for the multiverse..

  6. James

    Yeah, sorry Cormac, must have been in a bad mood when I submitted my comment (not your fault!), and just possibly a bit tipsy…

    However, I think that the general understanding of basic classical GR amongst physicists – not even the general population – is a bit dire (never mind fancy inflational models, or attempts at QG). Witness your own recent postings about superluminal velocities of distant galaxies due to the expansion of the universe, or CIP’s Christmas Teaser about a beer can tragically falling into a black hole, for some examples.

    When I did my physics degree – back in the days of Galileo – GR was taught as part of a final year mathematical physics option which scared off most students. The limited time was mostly spent trying to cram some diff geom and algebraic topology into our heads so as to try to grasp the theory on a maths basis, and we had precious litle time left to wonder what it was all about.

    It was only some years later that the profound nature of diff invariance – “background independence” – and the shear meaninglessness of saying much about the relationship between things that don’t happen at the same point became clear. So, I just wish we could somehow move beyond “cartoon relativity” as we approach 100 years after Einstein came up with it.

    Best wishes for Christmas and the New Year!

  7. cormac

    ‘Witness your own recent postings about superluminal velocities of distant galaxies due to the expansion of the universe’
    I said nothing about superluminal galaxy velocity. This would indeed be in serious contradiction with GR. The theory of inflation concerns an exponential expansion of spacetime in the *early* universe, nothing to do with galaxies…

  8. James

    Oops, I guess apologies are due again!

    I was refering to your “Hubble puzzle” (but mis-remembered the details and was too lazy to go back and check). I seemed to recall (in error) that you had concluded that this acceleration would have distant galaxies at warp 10 by now…

    Still, that post did seem to highlight a lot of differing (and strongly held!) opinions about some theoretical and experimental results which have been known for a long time. I think it’s a pity that they are not better understood by all educated people as they rank are among the core ideas of our modern scientific world view (hence: Down with the rubber balloons and trampolines!).

  9. Aleksandar Mikovic

    Dear Cormac,
    The question “What is outside of the Universe” is a metaphysical one, and clearly it is outside of the scientific domain. However, it cannot be considered stupid or naive, because the “obvious” answer you gave, i.e. nothing, presuposes a beleif that everything that exists can be described by a spacetime with elementary particles and their interactions in it. However, if one beleives that mathematical truths exist independently of the spacetime, i.e. if one accepts the platonist metaphysics, then the answer is not “nothing” but it would be the platonic world of ideas. That the metaphysical beleifs affect the scientific thinking can be seen in several recent examples: the many worlds interpretation of quantum mechanics of Everett, De Witt and Deutsch or the Mathematical Universe theory of Max Tegmark, a renown cosmologist from MIT. The later theory is an example of a platonist metaphysics, where it is postulated that our universe is the same as the ultimate mathematical structure that describes it. Since there are many inequivalent mathematical structures, there are many universes, i.e. a multiverse is a natural consequence in this theory.

  10. cormac

    Hi Aleksander, long time no hear.
    Yes, the argument concerning mathematical truths existing independently of spacetime is an old, deep conundrum and should always be taken seriously.
    As regards the answer ‘nothing’, I should stress that this is an unfortunate shorthand for ‘there is no outside’, a better answer that arises from the definition of the term universe (all there is).
    That said, I accept that it may be too easy an answer, in the sense that there is a metaphysical aspect to the question that touches on the area of objective realism – which is why it’s such an interesting question!

  11. James


    I couldn’t disagree with you more. ‘Science’ etymologically derives from the Greek work for knowledge – and that’s all it is. We have to deal with what we see, hear, touch, or construct experiments to measure.

    The idea that the ‘perfect’ Lasagne exists in some Platonic Realm, and that all our efforts in the kitchen are just pale imitations of the perfect truth might be a good dinner party excuse for a less than perfect result – but that’s all it is…

    Let’s try to keep it real folks!

  12. Sir, as I feel, the question of what is outside the universe, is quite similar to one of this questions –
    One fine day, a ant asks his father – “what is beyond our colony, or this garden, or this house, or this residence? ”
    Any civilization, as I think, considers itself as the most intelligent form of existence, in his own Universe. The world, which may be very familiar to us, may be as alien as Dark Matter or Dark Energy or Black Hole, etc. to the ants or any other being.
    So, we have no right, or the proof, that we should call ourselve, as the most INTELLIGENT being on this earth or within this vast Universe. Considering ourselve as the most intelligent being, or the most stable existence at the apex, will only lead to the ignorance on behalf of us.
    Thus, this question of what lies beyond our Universe or beyond a limit which we cannot perceive or see, is just a limit to our ability and means. We cannot anyway straightforward deny that Nothingness exists beyond the Universe and accolade us with the award of most intelligent existence.

  13. cormac

    Siddarha, it depends how you define the term ‘universe’ – usually as ‘all there is’. Sounds lke you’re talking about the observable universe, which is not qiute the same thing..

  14. Sir, how can we suppose that we are acquainted by all of the Universe. We too are familiar or can be familiar with a particular or specific portions of the whole of the Universe. How can we say, we are the conscious of all of the Universe? I think, we may feel ourselves as too intelligent, but we somewhat resemble the ants, to some of the extent. And, we can’t expect us to be familiar with all the matter as they may mean something much larger that our perception.

  15. James

    We seem to have a lot of defeatist attitudes represented here concerning the notion of “outside the Universe”. It seems that there is a common notion that the concept is necessarily beyond human beings to comprehend: perhaps it should be consigned to the relm of “metaphysics” and therfore supposedly “outside the scientific domain” (what domain we might be left with I’m not sure – astrology? Leprechauns? (sorry – I’m half Irish so I’m allowed to say that under some convention or other)), or whether humans are not capable of understanding such questions, either because it will always simply be beyond our intellect, or that it might even be just human arroagance or vanity to just ask these qustions (this latter point of view often implying some religious/mystical beliefs even worse than leprechauns).

    So, in the week that saw Pope Benedict 16th admit on behalf of the catholic church that Galileo’s work wasn’t so bad afer all (and thus that perhaps they shouldn’t have persecuted him the way they did) we should take some pride in quite how far mere hman beings HAVE come in understanding the cosmos, from the very small to the very large, and perhaps have some more confidence in future progress!

    And here’s hoping for a bright future and happy new year to all!!

  16. Joe Nahhas

    Einstein’s Nemesis: DI Her Eclipsing Binary Stars Solution
    The problem that the 100,000 PHD Physicists could not solve

    This is the solution to the “Quarter of a century” Smithsonian-NASA Posted motion puzzle that Einstein and the 100,000 space-time physicists including 109 years of Nobel prize winner physics and physicists and 400 years of astronomy and Astrophysicists could not solve and solved here and dedicated to Drs Edward Guinan and Frank Maloney
    Of Villanova University Pennsylvania who posted this motion puzzle and started the search collections of stars with motion that can not be explained by any published physics
    For 350 years Physicists Astrophysicists and Mathematicians and all others including Newton and Kepler themselves missed the time-dependent Newton’s equation and time dependent Kepler’s equation that accounts for Quantum – relativistic effects and it explains these effects as visual effects. Here it is

    Universal- Mechanics

    All there is in the Universe is objects of mass m moving in space (x, y, z) at a location
    r = r (x, y, z). The state of any object in the Universe can be expressed as the product

    S = m r; State = mass x location

    P = d S/d t = m (d r/dt) + (dm/dt) r = Total moment

    = change of location + change of mass

    = m v + m’ r; v = velocity = d r/d t; m’ = mass change rate

    F = d P/d t = d²S/dt² = Force = m (d²r/dt²) +2(dm/d t) (d r/d t) + (d²m/dt²) r

    = m γ + 2m’v +m”r; γ = acceleration; m” = mass acceleration rate

    In polar coordinates system

    r = r r(1) ;v = r’ r(1) + r θ’ θ(1) ; γ = (r” – rθ’²)r(1) + (2r’θ’ + rθ”)θ(1)

    F = m[(r”-rθ’²)r(1) + (2r’θ’ + rθ”)θ(1)] + 2m'[r’r(1) + rθ’θ(1)] + (m”r) r(1)

    F = [d²(m r)/dt² – (m r)θ’²]r(1) + (1/mr)[d(m²r²θ’)/d t]θ(1) = [-GmM/r²]r(1)

    d² (m r)/dt² – (m r) θ’² = -GmM/r²; d (m²r²θ’)/d t = 0

    Let m =constant: M=constant

    d²r/dt² – r θ’²=-GM/r² —— I

    d(r²θ’)/d t = 0 —————–II

    r²θ’=h = constant ————– II
    r = 1/u; r’ = -u’/u² = – r²u’ = – r²θ'(d u/d θ) = -h (d u/d θ)
    d (r²θ’)/d t = 2rr’θ’ + r²θ” = 0 r” = – h d/d t (du/d θ) = – h θ'(d²u/d θ²) = – (h²/r²)(d²u/dθ²)
    [- (h²/r²) (d²u/dθ²)] – r [(h/r²)²] = -GM/r²
    2(r’/r) = – (θ”/θ’) = 2[λ + ỉ ω (t)] – h²u² (d²u/dθ²) – h²u³ = -GMu²
    d²u/dθ² + u = GM/h²
    r(θ, t) = r (θ, 0) Exp [λ + ỉ ω (t)] u(θ,0) = GM/h² + Acosθ; r (θ, 0) = 1/(GM/h² + Acosθ)
    r ( θ, 0) = h²/GM/[1 + (Ah²/Gm)cosθ]
    r(θ,0) = a(1-ε²)/(1+εcosθ) ; h²/GM = a(1-ε²); ε = Ah²/GM

    r(0,t)= Exp[λ(r) + ỉ ω (r)]t; Exp = Exponential

    r = r(θ , t)=r(θ,0)r(0,t)=[a(1-ε²)/(1+εcosθ)]{Exp[λ(r) + ì ω(r)]t} Nahhas’ Solution

    If λ(r) ≈ 0; then:

    r (θ, t) = [(1-ε²)/(1+εcosθ)]{Exp[ỉ ω(r)t]

    θ'(r, t) = θ'[r(θ,0), 0] Exp{-2ỉ[ω(r)t]}

    h = 2π a b/T; b=a√ (1-ε²); a = mean distance value; ε = eccentricity
    h = 2πa²√ (1-ε²); r (0, 0) = a (1-ε)

    θ’ (0,0) = h/r²(0,0) = 2π[√(1-ε²)]/T(1-ε)²
    θ’ (0,t) = θ'(0,0)Exp(-2ỉwt)={2π[√(1-ε²)]/T(1-ε)²} Exp (-2iwt)

    θ'(0,t) = θ'(0,0) [cosine 2(wt) – ỉ sine 2(wt)] = θ'(0,0) [1- 2sine² (wt) – ỉ sin 2(wt)]
    θ'(0,t) = θ'(0,t)(x) + θ'(0,t)(y); θ'(0,t)(x) = θ'(0,0)[ 1- 2sine² (wt)]
    θ'(0,t)(x) – θ'(0,0) = – 2θ'(0,0)sine²(wt) = – 2θ'(0,0)(v/c)² v/c=sine wt; c=light speed

    Δ θ’ = [θ'(0, t) – θ'(0, 0)] = -4π {[√ (1-ε) ²]/T (1-ε) ²} (v/c) ²} radians/second
    {(180/π=degrees) x (36526=century)

    Δ θ’ = [-720×36526/ T (days)] {[√ (1-ε) ²]/ (1-ε) ²}(v/c) = 1.04°/century

    This is the T-Rex equation that is going to demolished Einstein’s space-jail of time

    The circumference of an ellipse: 2πa (1 – ε²/4 + 3/16(ε²)²—) ≈ 2πa (1-ε²/4); R =a (1-ε²/4)
    v (m) = √ [GM²/ (m + M) a (1-ε²/4)] ≈ √ [GM/a (1-ε²/4)]; m<<M; Solar system

    v = v (center of mass); v is the sum of orbital/rotational velocities = v(cm) for DI Her
    Let m = mass of primary; M = mass of secondary

    v (m) = primary speed; v(M) = secondary speed = √[Gm²/(m+M)a(1-ε²/4)]
    v (cm) = [m v(m) + M v(M)]/(m + M) All rights reserved. joenahhas1958@yahoo.com

  17. Good Will Hunting from Boston

    Einstein (from the Grave) made me respond to this Question; What is outside the universe?
    I have read the Blogs and feel that we all must re-visit special realitivity, yes, lets go back in time 100 years. special realitivity was not proved until the early 1970’s with the sycronized atomic clocks experiment, so science has had a type of handy-cap on its own development for 70 years. There is no excuse to ignore Special realitivity. Special realitivity states that; if we could travel at the speed of light, (we and what ever physical object we were traveling in) our lenghth would shirnk to 0 as we attained the speed of light. In addition, the passage of time would stop completelty. Simply put, by attaining the speed of light we are in fact negating the affect of light speed. Special realitivity suggest aspects of our universe that science needs to study further, if matters lenghth shirnks to 0, it suggests that the lenghth of all matter in the universe is proportionately set by this pulling action, or exspantion of the universe with light matter being the engine that drives and not only streches matter but space time itself. If light speed was to increase or decrease for some unknown reason, all of the matter in the universe would proportionately shirnk or exspand and be reformulated to its new lenghth, this also suggests that the “Nothingness” outside of our universe plays an important role and has a special relationship with the exspantion process. The “Nothingness” or “void” could even be responsible for setting the speed of light at its current rate of speed. I believe the void and the universe is as connected as space and time is as first proposed in general relitivity, damm– that Einstein guy again! what a pain in the ass he is! lastly, referencing special relitvity, time standing still when you attain the speed of light suggest that time only exsists in the bubble of our universe and does not exsist in the void.

  18. Anil


    If “universe” is defined as “all there is”, then where or what is this “universe” expanding in? Doesn’t the universe require something to expand in? Does it have a boundary?

    In simple terms:
    Say U is universe and therefore “all there is”.
    Now, we say that everything is contained in U.
    So far, so good.
    But, looking from inside U, what we see makes us believe that the entire U is expanding!
    This raises the initial question – where or what is U expanding in? Does U have a boundary? OR, is U infinite, then we can assume that only the portion of space-time (in U) that we see is expanding and hence, does not require any further explanation (other than questions on infinte nature of U).

  19. Nagender

    May this is not the correct answer.Even in 21st century, we still think like stone age men.If a child puts up a question “why does an eclipse occurs?” do we say A Dragon swallows it or do we explain him?