Truly Immovable Rod

The Truly Immovable Rod (also called the Universal Stillpoint Rod) is a meme derived from a fa/tg/uy's story about how his dickish DM applied some very dodgy (but accurate if it was the real world and not the D&D world) physics to an Immovable Rod, judging that it remained immutably fixed in the universe while the planet they were on was moving (and thus setting it off, relative to the players, at several thousand miles an hour when activated). The very same fa/tg/uy later used an Immovable Rod as a siege weapon to destroy a castle, pissing off his DM.

It was considered that, since every celestial body is moving very quickly, anybody who placed such an Immovable Rod would never see it again, as their system left the stationary rod floating in the void. If this had happened a lot, there could be any number of Immovable Rods out there, simply biding their time until some unsuspecting and unfortunate planet happens to pass through the same region of space an*CLANG!*

WHAT THE FUCK WAS THAT?

Oddly enough, this was exactly quoted in Lucifer's Hammer, a book written by Larry Niven and Jerry Pournelle. In 1977. When a space station orbiting the Earth was suddenly hit.

Dickish GMs who wish to avoid such shenanigans should utilize a setting that is not based on planets, but instead, on an infinite plane of existence consisting solely of land extending in all four prime directions, and without proper "space" as we know it in this crapfest universe that we type this shit in. Or to use a Ptolemean universe, with a planet in the center of the Universe that doesn't move or spin, and sun, moon, stars and planets orbiting around it. Only then will the Immovable Rod function as advertised, thus avoiding the collision of physics and magic, and consequently, rendering all attempted castle demolitions using this method as invalid schlep comedy and copy-cat antics to be derided and punished with style. A final alternative is to claim it's relative to the nearest celestial body, or anchored to a manasphere a la Shadowrun.

Why this wouldn't Would Totally Work

Einstein's Theory of General Relativity (as well as many of the theories it superseded) tells us that there can never be a true "fixed point" in the universe, as all movement is based on the observer. For example you can cause a mountain to move simply by sailing past it on a moving object. To your perspective, you're sitting still, and the mountain is moving! This also applies to planets and entire star systems.

The dirty little secret of modern physics is that that's all bullshit. In 1948, some scientists who were much smarter than Albert Einstein figured out that if the Big Bang had happened, then it should have filled the universe with electromagnetic radiation that appears to be coming from everywhere at once equally. The existence of this cosmic microwave background radiation was experimentally verified in 1964. Now here's the kicker: the CMBR coming from one half of the universe is redshifted, while the CMBR coming from the other half of the universe is blueshifted, with the most strongly redshifted light and the most strongly blueshifted light coming from polar opposite directions. Redshift only occurs when the light source and observer are moving away from each other, and blueshift only occurs when they get closer. Since the CMBR is not coming from any particular object, but from space itself, the redshift and blueshift are caused entirely by Earth's movement relative to space itself. This means that not only is there a universally objective and privileged frame of reference, but we can precisely calculate Earth's speed and direction relative to it: 600 km/sec.

Why this wouldn't work anyway would work, but not how you expected it to

Relativity and CMBR aside, the only way an object could be immovable would be if it had infinite mass. Any object of infinite mass would subject everything in the universe to infinite g-forces, thereby pulling everything in the universe toward itself at the speed of light. This would be extremely bad for anyone trying to use the immovable rod as a weapon. The good news is that, since these g-forces are infinite, they are equal regardless of distance from the immovable rod, which means there are no tidal forces and no spaghettification; people will live long enough to be crushed into neutronium instead.

In short: the moment you activate the rod, the universe as you know it ceases to exists. You won?

External Links

• http://suptg.thisisnotatrueending.com/archive/1709686/ - suptg archive of the original thread.
• https://www.youtube.com/watch?v=9eKc5kgPVrA - a more scientific explanation of immovable objects.