# Expansion of the Universe: a two-part question **URL:** \ **Category:** Factual Questions\ **Created:** [June 24, 2005, 6:56am UTC](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639 "2005-06-24T06:56:18Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [June 24, 2005, 10:23pm UTC](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639/21 "2005-06-24T22:23:30Z")
> [@Stranger On A Train](#): > > How about this; take the example of a balloon, but instead of talking of taping pennies or drawing dots, make knots of the fabric of the balloon. Maybe when I’m paid to be a birthday clown and not an astrophysicist. 😉 ---
**Author:** ![aldiboronti](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@aldiboronti](https://boards.straightdope.com/u/aldiboronti)\ **Post date:** [June 25, 2005, 5:49pm UTC](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639/22 "2005-06-25T17:49:26Z")
> [@Stranger On A Train](#): > > The problem is that the explainations offered tend to idealize “space” as being this large elastic blanket in which we are embedded; people visualize the blanket as expanding uniformly, and the matter within it fixed in relation to the blanket. But matter is not space, and it is perhaps a better analogy to conceptualize atoms, planets, solar systems, and even whole galaxies as lilies floating on the surface of a pond; even if the surface of the pond gets larger as more water is added, and the lilies move away from each other; the increasing water flows around them but the flowers and pads are held firmly together by their vegetable structure. > > It is a property of matter (which is a form of energy that expresses itself gravitationally) that it distorts space about itself, causing other matter to be attracted and clump together–like the lilies–rather than spread out evenly; sort of like what Reagonomics did for finance moguls and their money. With large, galactic-scale structures gravity retards space from expanding. Even in larger structures, like [The Local Group](http://en.wikipedia.org/wiki/Local_group), gravitational attraction plays some effect, though very minor, on the expansion of local space. And even on much larger scales, enormously massive objects like [The Great Attractor](http://www.solstation.com/x-objects/greatatt.htm) have a more significant effect, causing galaxies to stream toward them (but still pulling away from each other). > > On more local scales, the electromagnetic force acts on atomic particles and holds together molecules, and the weak and strong nuclear forces act on subatomic particles and serve to keep nuclear particles clinging together; each is increasingly stronger, by many orders of magnitude, than its precedant, and all have much more of an effect to keep particles together than the expansion of space has in pulling them apart, in the same way that a raindrop will not “dilute” or rend apart a lilypad. > That’s a complicated answer, but the simple answer is…er, there is no simple answer. Electrons would still exist in their same shells at particular quanta from the nucleus, molecules would continue to form their present structures, et cetera, up to the point that local gravitational energy, which would be increasing, overwhelms the electromagnetic force. In the heart of the Sun, for instance, gravitationally-induced pressure prevents atoms from properly forming; instead, electrons zip back and forth, sliding between nuclei, without ever letting themselves become attached, like Jane Greer in [a '40s noir film](http://www.imdb.com/title/tt0039689/). This is called degenerate matter; it’s not quite atomic, but all the components are still intact. > > Squeeze further, as with a supernova (in which the lighter mass is blown away, leaving only a superdense core) and the electrons and protons cram together to make a bunch of neutrons and some radiation which disappears into the night like an alimony payment and leaves you with neutronium, held apart only by the particles’ unwillingness to share the same quantum state with one another, like two divas attending a party while wearing the same cut and color of dress. > > Add some more matter and eventually the whole party degrades into a massive orgy in which the participants become an inseverable mass of arms, legs, heads, and various other appendages; we don’t know exactly what goes on in there, and would probably be horrified if we found out (except for Bob Guccioni, who would be in a bathroom stall doing things we’d rather not think about), but we speculate that the matter would turn into a quagma, a fluid of quarks too dense for light to penetrate. > > Further compression gets us to a point past which we can even guess; the best speculation is that the particles arrange themselves in a matrix in which their quantum states “interlock”, allowing them to achieve smaller and smaller gaps, until they disappear faster than a played-out teen starlett, eventually condensing to a single, unified quantum state into one giant particle. It would take an enormous amount of mass to create this level of compression–quite literally, a universe’s worth–although we hope to simulate something like it for a very, very brief instant using larger and larger particle accelerators, and hence gain a understanding of what happens in the remote corners of space and the furthest reaches of time by looking at things that happen in a space too small to imagine. How cool is that? > > In any case, from what we understand right now (and while we are like the proverbial blind men feeling the different parts of the elephant, we have at least identified which smells the worst and have therefore concluded that we must be in the vicinity of an arse) the universe will not contract; the Hubble “constant” is actually a varying value that is slowly increasing over time and the energy balance of space is such that it appears that space will continue to expand away in perpetuity, until there is nothing left to look at but the formless nothingness of space accelerating away at c. And you though [2001: A Space Odyssey](http://www.imdb.com/title/tt0062622/) was boring? > > Stranger Bravo! A brilliant reply, **Stranger**. It’s enough to make one disappointed that the universe won’t contract! ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [June 25, 2005, 8:37pm UTC](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639/23 "2005-06-25T20:37:05Z")
I’m sorry for my ignorance, but I’ve got to ask this question. If the question has been answered above, I’ll re-read until I (hopefully) understand. My question is: Dosn’t the very word “Expansion” mean something (even if it’s something we don’t understand right now) is moving away from a “base” or stationary “thing?” What is this thing? What is space moving away from? What is it moving toward? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [June 25, 2005, 9:38pm UTC](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639/24 "2005-06-25T21:38:32Z")
> [@Jake](#): > > I’m sorry for my ignorance, but I’ve got to ask this question. If the question has been answered above, I’ll re-read until I (hopefully) understand. > My question is: Dosn’t the very word “Expansion” mean something (even if it’s something we don’t understand right now) is moving away from a “base” or stationary “thing?” > What is this thing? What is space moving away from? What is it moving toward? Space is expanding “away” from itself. If you could imagine being a single raisin in a freshly mixed batter of cinnimon bread, you’d see every other raisin expanding away from you, without reference to anything but yourself. Similarly, if you had two observers gravitationally isolated from each other in space (and widely seperated) they would see each other, and everything else, accelerating away from them; however, as they measure no effect of acceleration (no “virtual” D’Alambert forces as a result of inertia), they would each conclude that they are not in motion and are therefore the center of the universe, away from which everything is fleeing. There is, at least in threespace, no “away” or “toward” for universal expansion; the space between all objects just gets greater (and grows at a rate proportional to how distant they are). It is possible that this might have some kind of orientable property “outside” the universe (as in “branes” colliding), but it’s neither here nor there to us as we’re unable to experience or measure it. It’s not a trivial question, though; time clearly does have a preferred direction, and it is oriented “with” the expansion of space. The reason for this is unknown; we can justify it in terms of itself, i.e. entropy and causality, but we don’t fundamentally understand why one thing happens after another, and indeed, on the quantum level, causality does not hold in the classical sense. But hey, if George Lucas can ignore it in order to incestuously tie together every character in his saga, why should we agonize over it? 😃 Stranger [Previous page](https://boards.straightdope.com/t/expansion-of-the-universe-a-two-part-question/309639.md?page=1)