8 ms·
Hey, author here. As several of you have noted, there are a lot of tweaks to speed this simulation up - making it 2D increases (unphysically) the collision rate
by jasmcole 9y ago
Hey, author here. As several of you have noted, there are a lot of tweaks to speed this simulation up - making it 2D increases (unphysically) the collision rate, the particles have overly large collision radii, and the fragmentation threshold is quite soft initially but then quite high for small masses.
Regardless, I hope the video is fun - the sudden burst of fragmentation makes for quite the sight.
- sorenjan 9y agoThank you for this and previous articles, your blog is my favorite technical blog online. It's a great mix of technical detail and entertainment, and it's always impressive.
- jasmcole 9y agoThank you, that's very kind. I'd like to post more often, but real life does tend to throw a spanner in the works!
- skizm 9y agoThought you meant you were Neal Stephenson for a second! Quick question: If I haven't read the book, but want to, are there any spoilers in the article?
- aetherson 9y agoThere are spoilers for like the first few chapters, that's it.
- rtkwe 9y agoThere's one bit that could be a pretty big spoiler for the last book too.
- deleted 9y ago[deleted]
- madaxe_again 9y agoYou should definitely read the book, however. Hell, his entire corpus is one “whoa” after another. Still, Seveneves < Anathem, in my jumped up not so humble opinion!
- Florin_Andrei 9y agoIf you're interested in knowledge (broadly defined) then Anathem must be near the top of the list of your reads.
- turk184 9y agoI guess I'm not, then.
- wrinkl3 9y agoAnathem is probably Stephenson's best novel, and I say that as a huge fan of Cryptonomicon and Snow Crash. I've actually found his last few novels lacking, still struggling to finish The Rise and Fall of D.O.D.O. and REAMDE. I do wish he'd stop trying to reverse-engineer RPG settings and got back to his post-cyberpunk roots.
- aeorgnoieang 9y ago> The Rise and Fall of D.O.D.O. Thanks; I'm a little surprised I missed that!
- Florin_Andrei 9y agoREAMDE - don't take it seriously. The author basically just took a vacation and wrote a mindlessly fun action book. If you read it as such, it's pretty good. It's definitely written from a Western perspective, but it does have some pretty astute insights about East European mentalities and culture (I say this as someone straddling the fence between West and East culturally). DODO is not pure Stephenson. The personality of the other writer (Nicole Galland) quite clearly changes the atmosphere. It's the first NS book where characters' emotions are actually given some attention, and the first where female characters are described from a first-person perspective (in a way that's convincing).
- Florin_Andrei 9y agoThe first phrase in the book is a massive "spoiler". Well, kidding, sort of. But no, there are no major spoilers in the article. A few very minor ones. Go ahead and read the book.
- dwhabcdefg 9y agoIMHO it's a pretty fun book, great for a long train ride. However it's a little problematic in places, with some weirdness with eugenics and the role of women's reproduction. Trying to be vague to prevent spoilers.
- usrusr 9y agoYeah, that part seemed a little forced, as if he was working backwards from the title, to accidentally arrive at the good stuff that comes before that in the book. Which makes it a good read nonetheless.
- grey-area 9y agoYes. The moon blows up in the book. Sorry to ruin it for you.
- billpollock 9y agoI'd love to see your writing become a book! Four color, nicely bound. I'd love to read that.
- jasmcole 9y agoThanks! I am in the process of writing a wordpress to LaTeX converter, so watch this space...
- VectorLock 9y agoCan you post the source code?
- jasmcole 9y agoI will do after I've cleaned it up, it will appear at the blog repository at: https://github.com/jasmcole/Blog https://github.com/jasmcole/Blog
- Retric 9y agoUnless the relative velocity's are extreme they would merge on the first collision. So you get millions of small fragments from the first collision and one much larger one. On the other hand if it's got high relative velocity's they would both end up destroyed into millions of fragments. Picture firing balls of sand at each other. Moon even has a molten interior these fragments would be mostly liquid.
- foobarbecue 9y agoThe relative velocity's what?
- dahart 9y agoSuper fun thought experiment and project! Did you simulate n-body gravity, or just the Earth's? I couldn't tell from the project page or comments. My son just asked me yesterday what would happen if the moon went away, and he hasn't even read any Stephenson yet. Good question - another side to this though experiment! What happens if tides cease to exist? Could that cause enough change in the oceans or weather to pose a threat to life on earth? What if animals can't hunt at night anymore? What else do we rely on the moon for?
- hexane360 9y ago>Gravitational interactions between all bodies. I use an extraordinarily naive direct summation approach, which scales as O(N^2) and is horrible. A huge improvement would be to approximate forces from distant bodies with some kind of multipole expansion, and store masses in a balanced tree – this is known as a Barnes-Hut simulation.
- mirimir 9y agoDoes a ring develop if the simulation runs long enough?