Comments on: Portraits of a Universe in Motion

Portraits of a Universe in Motion

ZippityBuddha — Thu, 02 Feb 2006 13:31:29 -0800

Galaxy Dynamics GRAVITAS is an ongoing project to visualize and animate the dynamics of galaxies using supercomputer simulations.

By: pmbuko

pmbuko — Thu, 02 Feb 2006 13:50:11 -0800

I wonder how many variables they have in their formulas, because the resulting animations don't look look like they'd take a supercomputer to compute. Beautiful animations, regardless.

By: MetaMonkey

MetaMonkey — Thu, 02 Feb 2006 14:02:11 -0800

Incredible. Like visual music. Some of the best vids I've seen on the net. It's going to take a while to download all the HD vids but I must have them. A thousand thanks, ZippityBuddha.

By: JeffK

JeffK — Thu, 02 Feb 2006 14:06:27 -0800

It's also Kiefer Sutherland's favorite word.

By: super_not

super_not — Thu, 02 Feb 2006 14:08:43 -0800

It's also Kiefer Sutherland's favorite word. Yes JeffK, but do you know his least favorite word?

By: gurple

gurple — Thu, 02 Feb 2006 14:09:09 -0800

I wonder how many variables they have in their formulas, because the resulting animations don't look look like they'd take a supercomputer to compute. Beautiful animations, regardless. Computing transformations over time in a galaxy is horrifically computationally intensive. Even just a few thousand stars can really bog things down. There's a decent coverage of the various approaches here, but the upshot is that there's not likely ever going to be a way to do it that doesn't take a really big box or cluster.

By: JeffK

JeffK — Thu, 02 Feb 2006 14:15:11 -0800

The "N-word". Oh, and these animations are amazing. Just imagine how many civilizations are destroyed in this collision.

By: Balisong

Balisong — Thu, 02 Feb 2006 14:15:20 -0800

Ultra cool videos!! Thanks! This stuff goes on in my mind all the time.

By: Smedleyman

Smedleyman — Thu, 02 Feb 2006 14:16:53 -0800

"an exquisite ballet of mutual annihilation" Nice to know there are others out there who appreciate magnificent violence.

By: elpapacito

elpapacito — Thu, 02 Feb 2006 14:32:12 -0800

super_not: I'm guessing, nigger ?

By: brundlefly

brundlefly — Thu, 02 Feb 2006 14:36:53 -0800

Really neat stuff.

By: odinsdream

odinsdream — Thu, 02 Feb 2006 14:39:58 -0800

These look exactly like fancy versions of the "galaxy" screensaver that's included with xscreensaver on Linux. They're a little more colorful, but computationally intensive? Not to the point that anyone would notice if you cheated and used simpler math.

By: odinsdream

odinsdream — Thu, 02 Feb 2006 14:41:03 -0800

Also - I really enjoyed the link. Beautiful stuff.

By: brundlefly

brundlefly — Thu, 02 Feb 2006 14:42:59 -0800

Just imagine how many civilizations are destroyed in this collision. True. But I'd bet that the number of civilizations that will rise and fall during the course of the collision more than makes up for it.

By: headlessagnew

headlessagnew — Thu, 02 Feb 2006 15:00:47 -0800

The cross-section of interaction is extremely low for star collisions. Collisions between galaxies are far more common than collisions between stars, by several orders of magnitude. I've seen Dubinski present these simulations at several different conferences. One of the coolest things he mentioned is that his rendering is done on the fly. If I recall correctly, he uses a completely home-brewed code, using Smoothed particle hydrodynamics.

By: rlk

rlk — Thu, 02 Feb 2006 15:02:09 -0800

The Linux galaxy screensaver is definitely an attempt to reproduce some aspect of the beauty of galactic collision. However, it's a heavily simplified model. In the screensaver, a small number of invisible galactic cores interact gravitationally using n-body simulation. The star particles then interact with these cores, rather than each other. This way, the simulation is O(n+m) in the number of stars n and cores m, rather than O(n^2) in the number of stars, as is n-body. Nice summary link, gurple.

By: Freen

Freen — Thu, 02 Feb 2006 15:03:40 -0800

Scott Draves has been doing this for years, except, um, groovier. And distributed. It's fractal flames and it's called Electric Sheep.

By: Balisong

Balisong — Thu, 02 Feb 2006 16:09:11 -0800

Not to the point that anyone would notice if you cheated and used simpler math. We don't get great leaps and bounds in technology/learning when you cheat the math to make it look pretty. I assume there was not only a light point, but a spacific gravity for each, as well as a mass/gravitational constant, vector calculated by every other point's gravity, I immagine there must be surface tension, and newton's law for colliding bodies... If you are going to do it to the limit, do it right.

By: Eideteker

Eideteker — Thu, 02 Feb 2006 19:13:40 -0800

Hmm, watching these while listening to Tarkus = whoa. It's like being inside the 70s, man. And by the 70s, I mean 2001, which was filmed in the late 60s, but you get my drift.

By: Goofyy

Goofyy — Fri, 03 Feb 2006 01:42:55 -0800

I downloaded the 30MB AVI of the collision (Milkyway/Andromeda) and it only plays music. Missing codec? I figured a galactic collision would mostly be about shifting orbits, since even galaxies are mostly empty space.

By: Malor

Malor — Fri, 03 Feb 2006 01:48:22 -0800

odinsdream: if you'll notice, there are a lot of stars in each galaxy. They start pretty small, but they expand to immense size with very dense coverage. And, as others are pointing out, it looks like the effect is calculating every star compared to every other star, not just 'stars against galaxy centers'. Very lovely stuff. Thanks for posting it, Zippity.

By: sexyrobot

sexyrobot — Fri, 03 Feb 2006 02:36:12 -0800

headless is right...when galaxies collide, their stars rarely do, as they are very far apart compared to their diameters...a good visualization: stars are like ping pong balls in major cities (one in new york, one in chicago, one in l.a....) while galaxies are like dinner plates flying aroung your living room...they crash all the time