Outsider Immunity and Sponsored Magic

[sinker]

Clever, but no. I'm playing an outsider scion for today's generation!

Back on topic, though, we really have very little to go on as to what Outsiders are actually resistant, or vulnerable, to.  All the answers, here, to that effect are largely speculative, and representative only of the opinions of those giving them.

Acknowledged. That's what I want. I want what other people think so that I can make my thoughts more concrete or maybe see a different side (or any side for that matter, I personally didn't have a strong opinion).

[Tedronai]

There is, canonically, something special about Mortal magic as it relates to Outsiders.
Only mortal magic can bring outsiders to the mortal world (this may or may not hold true for the Nevernever, as well, but we some reason to believe that some other magic would suffice, there).

From there, it stands to reason that other qualities of Outsiders that relate to their interactions with magic would be similarly variable by its source.

[Becq]

That's just...wrong.
All else being equal, a 1kg object imparted with the same energy as a 10kg object will travel at 10 times the velocity, and both will possess the same momentum

Ok, I feel the need to express my inner engineer.

Momentum is mass times velocity (p=mv).
Energy is half mass times velocity squared (E=0.5(mv^2)).

mass ratio condition:  m2 = 10 * m1
equal energy condition: E = 0.5 * m1 * v1^2 = 0.5 * m2 * v2^2

Solving:
0.5 * m1 * v1^2 = 0.5 * m2 * v2^2
m1 * v1^2 = m2 * v2^2
v1^2 / v2^2 = m2 /m1 = 10
(v1/v2)^2 = 10
v1/v2 = 10^0.5 ~= 3.16
v2 = v1 / 10^0.5 ~= 3.16

p1 = m1 * v1
p2 = m2 * v2 = (10*m1) * (v1 / 10^0.5) = 10^0.5 * m1 * v1
p2 = 10^0.5 * p1 ~= 3.16 * p1

So the more massive object would have only a bit more than three times the velocity, and despite this would have more than three times the momentum, given equal energy.

Belial's statement was also incorrect, by the way.   An object with one tenth the mass but the same momentum would need to have 10 times the velocity.  While velocity is squared in the energy equation, mass is still a factor, so you end up with 10 times the energy for the smaller projectile.

And now back to your regularly scheduled thread. 

[Bruce Coulson]

It's speculated that a few mortal mages have specific abilities (or some hidden talent) that will let them more easily combat Outsiders.  That would probably only be a +0 Catch, though.

And I can see the argument that far from having more effect, Sponsored magic would be less effective against Outsiders.  Only mortal magic can even summon such beings to our reality; if you can't even summon a being, what possible power could you have over it?