Disc of particles around central star run for 1704 years

[TheReasonWhyGuy]

100,000 particles?

[DaegonPhyn]

@TheReasonWhyGuy It's a distribution of 100,000 gas particles. What this means in Gadget-2 is that there are 100,000 data points for a distributed gas. The gas is actually throughout the entire system and the "particles" are just specific locations data is being extracted from about the gas.

[TheReasonWhyGuy]

@DaegonPhyn hmmm.... I know what you're meaning, however being that I work on simulations like this, I find the specifics more interesting.

The 100,000 particles... are they simply attracted to a central point, or do they have gravity between each other?

N^2?

See, in the video it looks like rings form for a reason other than inter-particle gravity...

I've seen rings like that before without inter-particle gravity.

Would love to see a completed version of this, with planets formed...

[DaegonPhyn]

@TheReasonWhyGuy So maybe I'm explaining this poorly. In this particular simulation they're not exactly particles. They are points that represent properties of a gas spread throughout space at that specific point. They do have gravitational interaction between each other but the larger interaction is simply due to fluid dynamics. So things like viscosity and heating and other stuff. I'm not sure why the rings are forming actually, or at least I don't remember now.

[TheReasonWhyGuy]

@DaegonPhyn well viscosity would resist the force of gravity, which would via irregularities, would naturally form rings, followed by lumps. Viscosity, if im not mistaken, should resist that so long as there is enough gas... right?

[DaegonPhyn]

@TheReasonWhyGuy Right, but there's also not that much gas. The viscosity should be very small, but it might be enough to start building up irregularities. And considering there shouldn't be much irregularity in the system to begin with it's probably more likely that the viscosity helped form the rings than the gravitational effects.

[TheReasonWhyGuy]

@DaegonPhyn "it's probably more likely that the viscosity helped form the rings than the gravitational effects. "

Oh yeah, especially with a low gas density.

On top of that, assuming the gas started of symmetrical, it's likely that the natural rounding or variables in a computer, even if slightly, breaks the symmetry.

Maybe I'm wrong...

Anyway, yeah I'm willing to guess it's viscosity causing the rings.

GJ btw, great little video :)

[DaegonPhyn]

The issue is that it's very difficult to model planet formation in a simulation. It requires very high resolution and has to be set up such that the separate particles collide like solids would, but also will heat up and act like liquids in large collisions. Modeling phase changes in an astrophysical simulation is very difficult. I haven't seen anyone actually do it. There's tricks to get something similar...but it's not the real thing.

We also still don't fully understand planet formation.

[dt289]

There are no planets just rings.

Is there any good simulation (NOT ANIMATION) of planet formation on the Net ?!?!?!???

[Danarogon]

@dt289 the closest thing out there is universe sandbox... but its not perfect