Immovable Rod Question

[Crow]

What would happen if somebody (like a god or something), placed an immovable rod in the path of a planet's orbit? Does it burn up on "entry" or proceed to plow straight through the planet?

Also: Could a hulking hurler use multiple immovable rods as a platform (or brace) to pick up and throw the earth?

[Nebo_]

There is a weight limit.

[Chosen_of_Vecna]

What would happen if somebody (like a god or something), placed an immovable rod in the path of a planet's orbit? Does it burn up on "entry" or proceed to plow straight through the planet?

Also: Could a hulking hurler use multiple immovable rods as a platform (or brace) to pick up and throw the earth?

I'm pretty sure the Earth is capable of making a DC 15 Str check to move the rod.

[Ascension]

I'm pretty sure the Earth is capable of making a DC 15 Str check to move the rod.

Aye, many people forget that the "immovable rod"... isn't. It's just that "rod which is rather more difficult to move than a normal rod when activated" doesn't roll off the tongue nearly as well.

[Decoy69]

I'm pretty sure it's a DC30 Str Check. Also a planet is more than heavy enough to just barge it out of the way.

[Crow]

Ah, thanks for the clarification.

[CabbageTheif]

incidentally, you could make a knowledge (astrology) 30 check, take a bottle of air, teleport to space, place the rod in a predetermined spot (see the knowledge check) and when the planet moves into position the rod would enter the atmosphere. the rod is magical, and doesnt incinerate (but does heat up). as the earth keeps moving, the rod stays in position. lets say you knew that a person went to the same place for lunch everyday. so, with the heat it hits a person. with the heat and the velocity the planet is moving at (relative to the stationary rod) the person is assassinated. the rod then hits the actuall planet, planet makes a strength check, the rod does what rods do when moved.

then the adventurers have to play 'whodunnit'

[FMArthur]

Unless it went straight on into the planet, because you sharpened one end perfectly and the atmosphere passing through it heated it up considerably. Who says it has to stand against the whole weight of the planet? It probably still wouldn't work, but it's worth considering that it's not the entire planet hitting it, it's one specific area being struck by the rod, merely supported by the solidity of the materials connecting it to the rest of the world.

[Cuddly]

A better question is: what happens when a planet collides with a wall of force?

[RTGoodman]

incidentally, you could make a knowledge (astrology) 30 check, take a bottle of air, teleport to space, place the rod in a predetermined spot (see the knowledge check) and when the planet moves into position the rod would enter the atmosphere. the rod is magical, and doesnt incinerate (but does heat up). as the earth keeps moving, the rod stays in position. lets say you knew that a person went to the same place for lunch everyday. so, with the heat it hits a person. with the heat and the velocity the planet is moving at (relative to the stationary rod) the person is assassinated. the rod then hits the actuall planet, planet makes a strength check, the rod does what rods do when moved.

then the adventurers have to play 'whodunnit'

Oh, you people and your heliocentric model of the solar system. Assuming you're correct and your fantasy world is a planet revolving around a sun, I'd say it would take a heck of a lot more than a DC 30 knowledge check to be able to assassinate someone like this.

[Chronos]

Oh, you people and your heliocentric model of the solar system.

Exactly. If taking the rod into space and activating it worked that way, then why do you need to even take it into space to begin with? If the Earth moves, then any activation of the rod would send it (from the Earth's reference frame) flying off in some wild direction.

[Person_Man]

Also, its worth mentioning that an Immovable Rod is always moving. The world its on is spinning. The rod just stays in a stationary position relative to that world that its on, and those observing it from a close distance. But the name Relatively Stationary Rod doesn't have the same zing to it.

[Tsotha-lanti]

the rod is magical, and doesnt incinerate (but does heat up).

How do you figure that? It's a magic item, it's still vulnerable to whatever it would normally be vulnerable to; it just happens to get a save against effects that allow a save.

And have you calculated how fast an object that is sitting still objectively would be moving relative to the planet? Pretty important factor. (That's assuming you can even keep it still in space; would it start being still relative to the planet once it entered the atmosphere? How does it get decided what the rod is still in relation to? Why isn't a rod activated in the atmosphere still in relation to the planet?)

Also, you can't teleport things into mid-air; I don't see why you'd be able to teleport them into empty space.

This is all assuming planets are celestial objects revolving around a bigger celestial object, which is a pretty big assumption when talking about fantasy worlds.

[Overlord]

Aye, many people forget that the "immovable rod"... isn't. It's just that "rod which is rather more difficult to move than a normal rod when activated" doesn't roll off the tongue nearly as well.

Indeed, the "Immovable rod" is "immovable" in the same sense that the Titanic was "unsinkable."

These sorts of things just can't withstand impacts with large icebergs or planets.

[FlyMolo]

And have you calculated how fast an object that is sitting still objectively would be moving relative to the planet? Pretty important factor. (That's assuming you can even keep it still in space; would it start being still relative to the planet once it entered the atmosphere? How does it get decided what the rod is still in relation to? Why isn't a rod activated in the atmosphere still in relation to the planet?)

It's probably relative to the dominant gravitational field. Which, usually generated by large bodies at rest with respect to themselves, mean that the rod is unlikely to go flying off if taken into weirder cosmologies.

And the numbers you're looking for are: About 66 thousand mph, plus/minus about a thousand depending on time of day and latitude.

[Emperor Tippy]

As has been said, the real fun is Wall of Force. In a game with an earth like planet in a Sol like solar system the frame of reference suddenly becomes very important.

If you are sitting in the hold of a boat and cast Wall of Force, what frame of reference is it fixed in relation to. The boat? The planet (in which case WoF is pretty much the best way to get rid of a boat)? The star?

[Overlord]

As has been said, the real fun is Wall of Force. In a game with an earth like planet in a Sol like solar system the frame of reference suddenly becomes very important.

If you are sitting in the hold of a boat and cast Wall of Force, what frame of reference is it fixed in relation to. The boat? The planet (in which case WoF is pretty much the best way to get rid of a boat)? The star?

Well, I think it's pretty obvious that the rules require the Wall to be fixed in relation to the surface of the planet, in the same sense that a normal wall is fixed in relation to the planet. Except a Wall of Force is indestructible.

[CabbageTheif]

curse you all and your logic! it would have been the perfect crime if it wasnt for your meddling truth tables and your stupid P->Q statements!

if the rod moves in relation to the large celestial body it is near, then what would happen if it was in space (and to an above statement, you dont teleport the rod, a wizard with a bottle of air teleports into space)

[Ascension]

What is this "space" people keep talking about? Is it one of the demi-planes?

[FlyMolo]

What is this "space" people keep talking about? Is it one of the demi-planes?

*ahem* Spelljammer.

And the rod would be fixed according to the location and spin of the dominant gravitational field. So depends where you are.

[Guildorn Tanaleth]

curse you all and your logic! it would have been the perfect crime if it wasnt for your meddling truth tables and your stupid P->Q statements!

You're confusing logic with reality. Totally different things.

if the rod moves in relation to the large celestial body it is near, then what would happen if it was in space

It would move (or fail to move) relative to whatever body was exerting the greatest gravitational pull on it at the time. This would mean that, in your proposed murder scenario, the rod would be hurtling towards the planet up until the planet got close enough to overcome the nearby star's gravitational pull, after which point the rod would just be stuck in a stationary "orbit" around the planet until something else pulled it away.

[CabbageTheif]

And the rod would be fixed according to the location and spin of the dominant gravitational field. So depends where you are.

so in a heliocentric universe an immovable rod would orbit the sun? or would it move with the solar system it was in as that solar system moves through space, because if the second is the case then a knowledge check of 100 might allow you to assassinate someone in my aforementioned scenario.

[FlyMolo]

It would move (or fail to move) relative to whatever body was exerting the greatest gravitational pull on it at the time. This would mean that, in your proposed murder scenario, the rod would be hurtling towards the planet up until the planet got close enough to overcome the nearby star's gravitational pull, after which point the rod would just be stuck in a stationary "orbit" around the planet until something else pulled it away.

Conceivably, what with random teleportation effects and such, this has already happened, and given enough time, there could be immovable rod mines up there in stratosphere. Actually, closer to the moon.

And maybe it's designed to stay in the same reference frame after activation, to prevent them being changed by wrapping them in sufficient lead.

[CabbageTheif]

Conceivably, what with random teleportation effects and such, this has already happened, and given enough time, there could be immovable rod mines up there in stratosphere. Actually, closer to the moon.

with enough imoveable rod buildup, would it have its own gravity? and, if the greater of the gravitational pulls were the rods themselves, would they remain stationary in relation to themselves...is that possible?

[FlyMolo]

with enough imoveable rod buildup, would it have its own gravity? and, if the greater of the gravitational pulls were the rods themselves, would they remain stationary in relation to themselves...is that possible?

To pull a douglas Adams "There's another theory which states that this has already happened", what you're describing is a planet. with a core that's impossibly hard to deconstruct.

[Corolinth]

A better question is: what happens when a planet collides with a wall of force?

It doesn't. It casts Mordenkainen's Disjunction.

[AslanCross]

with enough imoveable rod buildup, would it have its own gravity? and, if the greater of the gravitational pulls were the rods themselves, would they remain stationary in relation to themselves...is that possible?

I think that would require a mass of immovable rods bigger than the planet.

And yeah, as has been mentioned, this would depend a lot on your cosmology. If your Material Plane involves a planet like Earth in a heliocentric system, it might work. (Though certain spells like nailed to the sky seem to assume a spherical planet.)

[Collin152]

A better question is: what happens when a planet collides with a wall of force?

I argue that the wall collides with the planet.

[Ascension]

*ahem* Spelljammer.

That's not necessarily canon in 3.5. I'd say the round vs. flat earth question and the "does space exist" question are entirely up to the DM.

[FlyMolo]

I think that would require a mass of immovable rods bigger than the planet.

Depends on the density, but fairly logical. About that size, give or take a couple billion tons.