# Strings/Universe: Which am I closer to in size? **URL:** \ **Category:** Factual Questions\ **Created:** [February 24, 2010, 7:36pm UTC](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296 "2010-02-24T19:36:30Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [February 26, 2010, 12:33am UTC](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296/21 "2010-02-26T00:33:27Z")
> [@Quercus](#): > > OK, you’re going to have to explain the ‘not a coincidence’ part. Seconded. Star----\>Proton----\>Planck mass Ratio? And why? ---
**Author:** ![SenorBeef](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senorbeef/32/2220_2.png) [@SenorBeef](https://boards.straightdope.com/u/SenorBeef)\ **Post date:** [February 27, 2010, 6:12pm UTC](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296/22 "2010-02-27T18:12:30Z")
> [@Supdog](#): > > If the universe is around 13.5 billion years old, and nothing travels faster than the speed of light, how can it be this big? > > I’ve heard theories that during, and shortly after the Big Bang, that the “inflation” could have been faster than the speed of light. Is this why the universe can be the size that it is? > > For arguments sake, let’s say the the Big Bang happened at the center of the observable universe and expanded outward at the speed of light. That would make the universe 27 billion light years wide. Right? Now lets say that for a brief period of time, the inflation was faster than the speed of light. It would be “wider” than 27 billion light years, but I wouldn’t think that it would be wider on the magnitude that it is. > > How is this possible? I’ll probably botch something here, but here’s my understanding: Everything is moving away from everything else that’s not gravitationally bound to it. Space is essentially being created everywhere, in every direction, to the tune of 72km per second per megaparec. (See [Hubble’s Constant](http://en.wikipedia.org/wiki/Hubble%27s_constant)). In effect, this means that the further you are from something, the more space between you and it is being created, and hence the faster you’re moving apart. The velocities of the objects moving away combined with more space being formed between them can mean that their total velocity relative to each other can exceed the speed of light. So our “observable universe” isn’t limited by our technology to view it, but rather the light from some parts of the universe will never get here because space is being created between us faster than the light can travel. The universe could be orders of magnitude greater than what we see, and we’d never know it by direct observation. We think we may have some idea of the size, but it’s based on inferring a lot of stuff and may be flawed. Cosmic inflation plays a role here, but I don’t understand it well enough to describe it properly. ---
**Author:** ![Animastryfe](https://avatars.discourse-cdn.com/v4/letter/a/8797f3/32.png) [@Animastryfe](https://boards.straightdope.com/u/Animastryfe)\ **Post date:** [February 27, 2010, 6:20pm UTC](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296/23 "2010-02-27T18:20:39Z")
> [@RaftPeople](#): > > What a perfect question: we have 2 completely opposite but correct answers. The two answers use two criteria. The first one answered in terms of magnitude, while the second was in terms of absolute size. ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [February 27, 2010, 7:18pm UTC](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296/24 "2010-02-27T19:18:21Z")
> [@Animastryfe](#): > > The two answers use two criteria. The first one answered in terms of magnitude, while the second was in terms of absolute size. Yes, I was aware of that, but it was entertaining because the thread was already down one path, so when I read that response, it took me a second to shift models and realize that, not only did the math make sense, it technically answered the op correctly. [Previous page](https://boards.straightdope.com/t/strings-universe-which-am-i-closer-to-in-size/530296.md?page=1)