Bags of Holding.

[S_Grey]

Recently I had a debate about this particular branch of items with a friend of mine. It did in fact end with both parties being dissatisfied with the other's argument.

So I'd like to know what the playgrounders think, if they are so inclined to share on this topic:

Are the contents of a bag of holding subject to the forces surrounding it, such as gravity and momentum?

"This appears to be a common cloth sack about 2 feet by 4 feet in size. The bag of holding opens into a nondimensional space: Its inside is larger than its outside dimensions. Regardless of what is put into the bag, it weighs a fixed amount. This weight, and the limits in weight and volume of the bag's contents, depend on the bag's type, as shown on the table below.

Error table not found

If the bag is overloaded or if sharp objects pierce it (from inside or outside), the bag ruptures and is ruined. All contents are lost forever. If a bag of holding is turned inside out, its contents spill out, unharmed, but the bag must be put right before it can be used again. If living creatures are placed within the bag, they can survive for up to 10 minutes, after which time they suffocate. Retrieving a specific item from a bag of holding is a move action -- unless the bag contains more than an ordinary backpack would hold, in which case retrieving a specific item is a full-round action...."

[Amoren]

Hmmm, it only mentions that the bag of holding spits out its contents when the bag is turned inside out, rather than being turned upside down with its opening towards the ground. If the contents were affected by gravity, the contents should spill out in that situation as well.

[S_Grey]

It doesn't actually mention anything about what happens if the bag is turned upside down. The contents may very well spill out.

[Amoren]

And if they did, then they would be affected by gravity. I'm still inclined to believe that the contents are not, due to the aspect of it being an extradimensional space, even if its only while the bag is closed.

[S_Grey]

That was another interesting point in our debate. The bag of holding is listed as nondimensional space, not extradimensional space like the portable hole. One of us took the meaning of this to be that nondimensional space is space that is whithin a plane of existance, but doesn't take up any actual space, and that extradimensional space is space in a different plane.

[FaradayCage]

If the contents of the interior of a bag of holding were subjected to the gravity of the world it's exterior is located in, the bag would have a weight equal to it's empty weight plus the weight of it's contents - not the fixed weight the DMG indicates. By the equivalence principle, the contents are also not subject to external forces.

Ergo, the contents do not fall out when the bag is upended, nor are they jostled around by a bit of rough and tumble.

PHYSICSED!

[SSGoW]

Perhaps the BoH's space is fixed but when you turn the BoH upside down you turn that space upside down BUT not the contents, thus now the contents have no where to sit (and fall out) and the gravity inside the bag is still pointing the same way, you just removed the floor.

I wish I could draw a diagram of this... Actually when I get to my computer ill try.

So gravity always is down (or none?) and it isn't the outside world's gravity that makes it fall out at all. If you were in a reverse gravity field and had the BoH open nothing would come out cause the gravity IN the BoH is still pushing everything against the solid floor of said bag....

EDIT: I made a diagram however my paint skills suck so I don't even want to show it. However if I can figure out how to put it on here it might make sense of my explanation of the Bag of Holding.

http://i49.tinypic.com/33cnods.png

I think that worked...

Anyways my thoughts on the BoH is basically.. The wizards who makes them give them gravity, however they make it point "down" and it never changes BUT it is not connected to the bag itself. Think of one of those sand timers, even if you turn the glass the sand still falls one way (though in this case it is because they have their own gravity that has nothing to do with outside gravity or the glass around it hahaha).

[Mnemnosyne]

Okay...now, you're floating in wildspace outside the reach of any planes of gravity at all. Define 'upside down' in relation to the bag, which apparently has its own internal gravity?

[S_Grey]

I like the interpretation of the bag having its own internal gravity. One of the things that came up in our debate was whether or not the objects inside of the bag just floated around, instead of resting on the bottom.

Now what about momentum? Are the objects inside of the bag jostled around if the bag is? Are the objects inside affected if the exterior of the bag is pushed?

[Mnemnosyne]

Yeah, that's what I'd figure. That the bag has its own gravity that always points away from the opening.

SSGoW's interpretation has some oddities where the internal gravity seems to be fixed relative to an external position, and if you rotate the bag the gravity inside remains fixed relative to an external position...but it doesn't hold up when you take into account movement to places where the gravity plane is different.

[Dire Panda]

What FaradayCage said.

If you want to get more in-depth about gravity, here's my Layman's Guide to General Relativity. All objects move along geodesics (basically the line segment of shortest distance) in spacetime. Spacetime's curvature, and hence the paths the geodesics take, is determined by concentrations of mass via the Einstein equation.

Now to apply this to the Bag of Holding. If we say that item's magic can produce arbitrary spacetime curvature, then it's entirely possible to create an object with the bag's stated properties. You'll need to modify spacetime's topology somewhat so that there's a separate 4-space connected to our universe by a single point - the bag's opening. That 4-space can have any curvature you like (it's magic, after all!), so internal gravity is entirely doable. Constraining that point to move with the bag (again, as a function of the magic's ability to produce arbitrary curvature), we end up with an internal "space" that has its own gravity and is completely unaffected by the bag's motion. Kick the bag, shoot it out of a cannon, whatever's inside will be fine.

It's been a few years since I took GR, so don't quote me on any of this, but it should be good enough for D&D.

[Invader]

The items in the bag are not subject to any outside forces. You can lay the bag down and smash it all day log with rocks and nothing inside the bag will be harmed. The same holds true for gravity. Regardless of whatever gravitational force effects the bag from the outside the inside isn't subject to the same force.

Just turning the bag upside down doesn't cause anything to fall out. Think of the inside of the bag as black void with no up, down, left or right. Whenever you reach your hand into the bag it enters from a random spot in that black void and since there's no up or down there's no way for something to fall "out".

At least that's how I'd interpret it.

[Slipperychicken]

With Bags of Holding, just remember to sheathe every weapon you stick in there, and cover every sharp surface, or else your DM could screw you over with that.

[S_Grey]

The items in the bag are not subject to any outside forces. You can lay the bag down and smash it all day log with rocks and nothing inside the bag will be harmed. The same holds true for gravity. Regardless of whatever gravitational force effects the bag from the outside the inside isn't subject to the same force.

Just turning the bag upside down doesn't cause anything to fall out. Think of the inside of the bag as black void with no up, down, left or right. Whenever you reach your hand into the bag it enters from a random spot in that black void and since there's no up or down there's no way for something to fall "out".

At least that's how I'd interpret it.

I have trouble thinking of the interior of the bag being like that, because if it was, how would sharp objects inside of the bag pierce it?

[Invader]

I have trouble thinking of the interior of the bag being like that, because if it was, how would sharp objects inside of the bag pierce it?

Because there's still a finite amount of space in the bag.

[SSGoW]

Yeah, that's what I'd figure. That the bag has its own gravity that always points away from the opening.

SSGoW's interpretation has some oddities where the internal gravity seems to be fixed relative to an external position, and if you rotate the bag the gravity inside remains fixed relative to an external position...but it doesn't hold up when you take into account movement to places where the gravity plane is different.

The way I see it is like this... You are in a big box, and the box is being turned (one side is an opening and eventually it will be underneath you). You keep falling toward the earth since that is the way yourgravity is pulling you, however eventually (since you are not connected to the box just in said box) you will come to the opening and you will fall out of. Sure the Box is being effected by gravity too. Actually think of the box as a metal box and having a magnet be its gravity. No matter what way the magnet is pulling your box, you will continue to be pulled in one direction. You change the position of the box, the position of the box's magnet but you will always go in one direction gravity*. You will eventually fall out of the opening.

So I like to think that the items in the Bag of Holding have their own gravity (always pointing in one direction)* which is not always pointing to the bottom of said bag. This also explains why a BoH doesn't give you the item like a Handy Haversack does.... Actually a Handy Haversack is an example of when the gravity is pointed toward the opening... It is really really easy to get stuff out of, and since the outside world's gravity is (usually) pointing the opposite way... Everything "floats" at the top of said sack.. Hmmm

*Not responsible for injuries resulting from a metal box turning and spinning...

This would be so much easier to explain in person haha.

:smallsmile:

[Eldonauran]

Are the contents of a bag of holding subject to the forces surrounding it, such as gravity and momentum?


My answer would simply be "no". The bag is an enchanted magical item that seperates the two spaces from each other. It doesn't allow interaction between the two spaces except at the opening in which something can physically (or the equivalent) reach through.

[hobbitkniver]

It doesn't actually mention anything about what happens if the bag is turned upside down. The contents may very well spill out.

What if you tie it shut?

[Fyermind]

Yes to momentum, no to gravity.

Yes to momentum because they still have mass even if there aren't forces acting on them, and because they have velocity, otherwise they would never exit the bag. More practically, if I am in a flying castle moving very very fast, and I spill out the contents of my bag of holding, its contents should have the same velocity as the bag. If I am in said castle and I grab an item out of it, it should exit at the same velocity as my hand. This is to prevent infinite jerks as the item is removed. As to items being placed in a bag of holding, they maintain momentum relative to the bag's opening when they are placed within. Thus a sharp object tossed in carelessly could destroy the bag from within, as could that kobold trying to claw his way out.

[Jack of Trades]

My two cents.

The contents of a bag of holding are not subject to gravity or momentum while inside the bag. Upon removal of the object from the bag, the object is now subject to affects of gravity and momentum.

Non-dimensional space means no up or down. Gravity is a warping of space (Einstein's view). The opening in the bag is an interface between the non-dimensional space of the bag and the normal dimensional space. What happens on one side of the interface does not affect the other side of the interface.

Think of the inside of the bag as Las Vegas. :smallbiggrin:(Americans will get the joke.)