7 ms·
Scale of the Universe
- deleted 16y ago[deleted]
- JonnieCache 16y ago>Why can't Google maps do that? Because, fortunately, the world is not vector-based :)
- erikig 16y ago> Because, fortunately, the world is not vector-based :) Why 'fortunately'?
- JonnieCache 16y agoI don't know. Actually thinking about it, viewed in terms of quantum mechanics the universe from our scale looks more like a bitmap image than a vector image. (Note that I have no actual knowledge of quantum physics for the purposes of this meandering nonsense of a comment.)
- erikig 16y agoI ask because initially I tended to look at the universe as a really large bitmap - what is the smallest observable particle - thats our bit, everything else is a bitmap. As I looked at the original post however I keep thinking that the purpose of physics is to determine standard rules and definitions that work across the entire scale. That uniformity, comforting as it is, would make the entire thing vector-like (I think).
- pixdamix 16y agoHow not to feel sooooo small and insignificant after that !?
- JonnieCache 16y agoYour only hope is powerfully mindbending chemicals.
- praptak 16y agoBy looking at the smallish end of the scale, of course. I am so much bigger and more signifigant than a cilliate protist!
- hugh3 16y agoSome people get depressed when they find out how huge the universe is... What is the big deal about bigness? A cow is much bigger than you, but it is a ridiculous animal and you are a valuable person. You know it's a cow. It doesn't know anything. it just stands there eating grass (grass!) and mooing. And if it were bigger, that would only make it more ridiculous. - David Deutsch
- erikig 16y agoDavid Deutsch, while making valid philosophical/metaphysical points, exhibits symptoms of a serial cow-tipper.
- glhaynes 16y ago"You're really only very small, and life flows on within you and without you."
- elai 16y agoIt's inspiring.
- scalyweb 16y agoAnd I was getting big-headed this morning for solving a silly problem for a client. Thanks for reminding me of my place. :)
- Marticus 16y agoThat... is spectacular...
- SZW 16y agoIt is! I don't have particularly clever thoughts about it, but I want to say it's amazing. Thanks a lot to the creator!
- jcfrei 16y agoit's still nice but it's been here before: http://news.ycombinator.com/item?id=1835460 http://news.ycombinator.com/item?id=1835460 BTW: since there's no search feature to check for older posts, I suggest you use google: site:ycombinator.com
- tonyskn 16y agoor http://www.backtype.com http://www.backtype.com
- Stasyan 16y agosearchyc.com
- ronnier 16y agoI've also created an API to look up URLs that have been posted to HackerNews. http://api.ihackernews.com/getid?url=http://uploads.ungrounded.net/525000/525347_scale_of_universe_ng.swf http://api.ihackernews.com/getid?url=http://uploads.unground...
- vanni 16y agoEven earlier: http://news.ycombinator.com/item?id=1261816 http://news.ycombinator.com/item?id=1261816
- latch 16y agoAlways been amazed at how really small things (atoms) look a lot like really big things (solar systems) (ya, ya, same forces...)
- gjm11 16y agoThey don't really -- in particular, the picture you might have from high-school physics lessons of electrons orbiting a nucleus like planets orbit a star is really wrong. And it's not really the same forces; the way an atom looks is mostly down to the electromagnetic force, whereas the way a solar system looks is mostly because of gravity. On the other hand, it is true that Newtonian gravity and the electrostatic force (i.e., what the electromagnetic force becomes when you make the approximation that there are no moving charges) have very similar mathematical forms, with the same sort of differential equation governing them. What Newtonian gravity and electrostatics have in common is mostly that they are convenient simplified approximations; you could say that they're so similar because there's a limited repertoire of differential equations simple enough to make good approximations. (There's a bit more to it than that; for instance, inverse square laws fall naturally out of the geometry of a 3-dimensional world.)
- mcritz 16y agoIndeed, some patterns in nature might look familiar. For instance, stellar matter in novae seem a lot like clouds but only because human psychology is really good at pattern recognition. As for Newtonian physics versus relativity Brian Green’s Elegant Universe TV show (and book) does a great job illustrating the differences in an entertaining way. If you’re into that type of thing. http://www.pbs.org/wgbh/nova/physics/elegant-universe-einstein.html http://www.pbs.org/wgbh/nova/physics/elegant-universe-einste...
- jerf 16y ago(Elaborating:) Electron shells "look" more like this: http://www.absoluteastronomy.com/topics/Azimuthal_quantum_number http://www.absoluteastronomy.com/topics/Azimuthal_quantum_nu... They really don't resemble gravity-based orbiting in solar systems at all.
- 16y ago
- dansingerman 16y agoCan someone explain to me if the Universe is supposed to be 14,000,000,000 years old, how can it be estimated to be 93,000,000,000 light years wide? Assuming the Big Bang, doesn't that imply the 'outer matter' must have an average velocity of about 3.3 times the speed of light?
- benihana 16y agoAccording to general relativity, space can expand faster than the speed of light. So while what we can see is limited by the speed of light, the size of the universe is not.
- cromulent 16y agoBecause the distance has also grown since the light travelled. It's expanding. http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN
- ntownsend 16y agoAnd on that note, the creator has made the common mistake of performing the calculation speed_of_light * age_of_universe to determine the radius of the observable universe. Space has expanded during the lifetime of the universe so the objects that emitted light at the edge of the observable universe have moved further away since emitting the light. The estimated distance to the edge of the observable universe is more like 47 billion light-years: http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN The visible universe, however, is a bit smaller since we can only see as far as the surface of last scattering: http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation http://en.wikipedia.org/wiki/Cosmic_microwave_background_rad...
- gjm11 16y agoThe answers from benihana and cromulent are correct, but the following may possibly be a useful thought experiment. Imagine a balloon (our universe) with lots of ants crawling on it (photons moving at the speed of light). The ants can't walk any faster than 2mm/s. They can't take a message from any part of the balloon to any other faster than that. (And, let's suppose, there's nothing living on the balloon that moves faster than an ant.) Now someone blows up the balloon; it gets much bigger. Its expansion moves the ants apart much faster than 2mm/s. But it's still true that if you have two points 10mm apart, no ant can get from one to the other in less than 5s. Suppose the balloon starts off rather small, and then is blown up very rapidly: perhaps it grows abruptly from 100mm across to 1000mm across in less than a second. (The corresponding phenomenon for the universe is called "inflation"; it explains many otherwise puzzling things but no one knows for sure whether it really happened.) Then it may happen that the only ants that have been able to reach one particular place on the balloon (our observatories) have come from a smallish fraction of the balloon (the observable universe).
- CallMeV 16y agoAw, they changed the theme tune.
- bungula 16y agoTry doing a fast zoom out from the smallest to the largest. If you do it at just the right speed, it will give you serious goosebumps.
- heed 16y agoIf there is a minimum physical length, that is a planck length, does that mean that nothing is technically continuous? Or, is it possible to imagine 'half a planck length'?
- baddox 16y agoThat's a great question. I'm not sure how motion (and thus transfer of information) would be possible in a discrete universe. A somewhat related question is whether the universe is the result of computation. Many thinkers have chimed in about the physics and philosophy of this sort of thing: http://en.wikipedia.org/wiki/Fredkin_finite_nature_hypothesis http://en.wikipedia.org/wiki/Fredkin_finite_nature_hypothesi... http://en.wikipedia.org/wiki/Digital_physics http://en.wikipedia.org/wiki/Digital_physics http://en.wikipedia.org/wiki/Digital_philosophy http://en.wikipedia.org/wiki/Digital_philosophy
- Devilboy 16y agoThe quantum world is indeed discreet, and (as far as we know) half a planck length doesn't make any sense physically.
- brianpan 16y agoI think of it as: Newtonian physics makes down to a certain scale where it is no longer accurate. Quantum makes sense down to a Planck length where beyond that, we may need different theories.
- Aron 16y agoI would point out that the ant is precisely in the middle of the scale between small and large. Think about that, grasshopper.