

Physicists Discover a Whopping 13 New Solutions to Three-Body Problem - soofy
http://news.sciencemag.org/sciencenow/2013/03/physicists-discover-a-whopping.html

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Noughmad
After seeing the animations and reading the article, I am somewhat skeptical
about the stability of these orbits. They are rather long and have plenty of
near-misses. Even if they are stable in the sense of a pure 3 body problem, at
close distances stars don't behave as point objects anymore. Instead, you have
things like tidal forces and matter around stars.

Additionally, all the near misses makes it difficult to calculate the orbits,
even with variable step size.

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mturmon
You've been downvoted, and I don't know why, because you raise a worthwhile
point ("will these be observed in real systems?"). In addition to the non-
ideal factors you mention, there may also be the possibility of mass exchange
in the close approaches.

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danmaz74
If you want to go directly to a visualization of the solutions:
<http://suki.ipb.ac.rs/3body/>

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jbochi
I have added all the solutions to my html5 gravity simulation project here:
<http://jbochi.github.com/planets/>

PS: Some of the configurations are not stable with my code. I'll try Runge-
Kutta.

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gngeal
Hah, my high school memories - a graphical gravity simulator project for my CS
class, leaking energy due to the use of a very naive integrator (the Euler
method for ODEs).

You might want to try Stormer-Cowell, it's sort of a gold standard in orbit
simulation.

UPDATED: Hmm, now that I think of it, this would probably profit more from a
variable step method. Some of the close approaches seem to be really close for
a fixed-step integrator.

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jbochi
Thanks! I did not know Stormer-Cowell, but googling it, I've found a
comparision to DROMO, suggesting that it's even more stable:
[http://www.congrex.nl/11c01proceedings/Papers/2225317%20Pela...](http://www.congrex.nl/11c01proceedings/Papers/2225317%20Pelaez.pdf)

I'll try both if I find the time :)

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gruseom
"What we did was the most simple-minded thing that you could do,"
Dmitrašinović says. "We were shocked when we discovered all these things, and
we were even more shocked when we discovered that they had not been discovered
before us."

~~~
leal
It's amazing how many things are discovered this way.

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modarts
As someone with an undergraduate level education in physics I find this stuff
pretty cool. Having a number of homework exercises for my graduate level
classical mechanics courses end with the fact that the solution degenerates
into a three-body problem, and therefore an unsurmountable task, this kind of
news gives me hope :)

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brador
Is there any simulation online where I can just click to add planets and watch
them move around each other? It's surprisingly relaxing...

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dokem
Here's one a made a while back. <http://horuff.me/static/content/grav/>

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srl
That's /really/ fun, thanks!

It doesn't work, though. On firefox 19.0.2 (archlinux), it seems to detect
clicks shifted a good bit to the right (maybe 100 pixels?), and a little bit
down. It looks like it's using whole-screen coordinates without correcting for
the position of the canvas.

It would also be cool if you could give some quantitative data below - the
total amount of kinetic/potential energy would be fun to watch, for instance.
(And graph it.)

You also seem to be using an inverse-square law, which is "incorrect" in a 2D
universe, but I suppose it makes it seem more natural.

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ChuckMcM
Those are some awesome orbits. There don't seem to be any solutions where all
three bodies are in the ecliptic? If so does that mean we would only see these
in the wild in a planet/star "capture" situation?

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im3w1l
Wow, that text scrolls slowly...

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anonhacker
when it rains, it pours.

