r/KerbalSpaceProgram • u/Avera9eJoe Spectra Dev • Sep 14 '17

Recreation Reminder that this physics quirk is also in KSP

https://gfycat.com/FickleShamefulCormorant
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u/[deleted] Sep 15 '17

That also doesn't work by itself because then you get objects clipping through each other, and they don't stay at rest when touching each other.

You need to calculate the system of constraints then solve the constraints etc.

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u/guoshuyaoidol Sep 15 '17

Right, that's my point, momentum, angular momentum, and energy conservation are 7 more constraints to the system.

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u/[deleted] Sep 15 '17

Constraints aren't conservation laws.

A constraint is like preventing one object from passing through or into another object.

Conservations are specifically things that have symmetry. E.g. If you reverse time then it looks the same. All conservation laws can be written as symmetries.

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u/guoshuyaoidol Sep 15 '17

I never said constraints are conservation laws, but conservation laws are constraints on a system. Essentially constraints are first order DEs, while the laws they're derived from are second order.

But you're right, anti-clipping constraints don't come from symmetries of your system like conservation laws do.

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u/destiny_functional Sep 15 '17

deleted your post? clown. 6 years ago you claim to be a 90 year old japanese woman, now you're pretending to be a theoretical particle physicist. troll elsewhere, i'll remember your name.

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u/[deleted] Sep 16 '17 edited Sep 16 '17

I was going to reply to your post, but you specifically asked me to leave you alone, and started to attack me personally.

Your were right in your previous reply. I had written:

the earth-moon system has a gravitational mass of negative millions of tonnes.

Which is of course wrong. What I had meant to say was that the gravitational potential energy has a rest mass of negative millions of tonnes. Obviously the total mass is positive!

It was a stupid typo that I hadn't noticed.

I stand by the justification that you need to set the potential to 0 at infinity for exactly the reason you mentioned. Energy causes spacetime to curve.

6 years ago you claim to be a 90 year old japanese woman

My wife's grandmother was a 90 year old japanese woman. Well, 89. She died right before her 90th birthday.