Gravity Is a Harsh Mistress

W. E. Coyote's Law of Cartoon Inertia: Objects in motion tend to stay at the same altitude until gravity is noticed.

—Vaarsuvius, Order of the Stick

Sometimes gravity doesn't work. Or doesn't work immediately. Or evenly. Or fairly. This takes the following forms:

Gravitational Cognizance: A character will not fall until they realize they should be falling. For example, running unknowingly off the edge of a cliff—or walking on the underside of a diving board. Especially dense or focused characters may need to have another character point out their vulnerability.

Creeping Gravity: Also known as Gravity Waves. Gravity will affect a character's body in sections i.e. legs, then torso and finally head. The character will demonstrate neither tissue damage nor pain as a result of this distortion, only on hitting the ground.^[1]

Varying Gravity: Characters will fall faster than a heavy object—ensuring that the object lands on them. Everything falls faster than an anvil. Sometimes gravity will even shift around the relative positions of objects. For example, a character and an anvil are falling side-by-side, when suddenly the anvil starts falling a bit slower and moves laterally so it is now directly above the character's head.

Dramatic Gravity: Gravity can be suspended for just enough time to give one last comment to your opponent. Gravity can also be suspended while a badly spooked character bobs up and down in mid-air while screaming.

Out On A Limb: Gravity is less powerful than other physical forces, including friction, tension, torsion and all the rest. Static electricity appears to be the most powerful physical force. This allows objects to be stacked on top of each other across an unlimited space or height;^[2] and will maintain stability even if the branch or beam they are standing on is sawed in half; so long as the pieces are touching. This also allows characters to balance an unlimited number of objects in their hands.

Counterintuitive Gravity: Items which should fall don't, when items that shouldn't, do. The traditional case is a character chased up a tree and out onto a limb, as above. It is reasonable for them to trust their weight to a branch while the chaser is cutting through it, because sawing the branch off will make the tree fall. The section being removed (and the character on it) remains suspended in mid-air while the rest of the item (plus whatever object or structure had been supporting it) falls, presumably forever.^[3] Diving boards and bridges are also prone to this effect. Or the item could just fall the wrong way.

Named for a line in The Tick whose title character complains about gravity working all too well at the time (luckily, he is Nigh Invulnerable). The author may or may not have stolen it from an earlier Garfield strip, which itself is a riff on the title of the novel The Moon Is a Harsh Mistress by Robert A. Heinlein, and where varying gravity is an important plot point. Which is in turn a play on the sailors' saying "The sea is a harsh mistress". Which probably goes back to The Bible's line "The Law is a harsh master" (Romans 7, 1-6). And then Cassandra Claire wrote something similar in The Draco Trilogy.

The non-PG version is "Gravity's one mean mother, huh?" or "Oh Gravity, thou art a heartless bitch". It's also used as the name of an achievement in the game Magicka.

See also Not the Fall That Kills You, Gravity Sucks and Variable Terminal Velocity. Gravity as a "power" that is easy to create is covered by Artificial Gravity and Gravity Master. Compare Gravity Is a Harsh Seamstress and Gravity Is Only a Theory. A related trope is Puff of Logic, when something that "shouldn't" exist but does promptly ceases to once an observing character points out why.

Examples of Gravity Is a Harsh Mistress include:

Gravitational Cognizance

Literature

In The Hitchhiker's Guide to the Galaxy flying is the art of deliberately (ab)using this trope. Specifically, throwing yourself at the ground and missing, and then making sure not to think about the fact that flying is impossible, or else gravity will notice you.

Western Animation

In an episode of Tiny Toon Adventures, Elmer Fudd teaches that as long as they don't realize there's no ground beneath them, they will not fall. At the end of the episode, the characters exploit this trope to pass over a gorge by stepping on thin air without looking down.

Creeping Gravity

Western Animation

Frequently seen in Looney Tunes cartoons.
- In nearly every short of his, Wile E. Coyote walks off the edge of a cliff, looking down and then at the screen in horrid realization before falling.

Varying Gravity

Western Animation

On more than one occasion in Warner Bros. shorts, a character who was falling to earth gently via parachute was handed an anvil by another character who was falling at the exact same rate and immediately went into a terminal velocity plunge.
Wile E. Coyote is intimately familiar with the variant in which gravity changes how strongly it affects objects in order to maximize the damage he suffers.

Dramatic Gravity

Western Animation

In the Looney Tunes cartoon High Diving Hare, Yosemite Sam was tricked into falling off a diving board by Bugs Bunny, and rose back up for a moment to say "Ah hate yew" before plunging again.
Tom of Tom and Jerry has suffered the "bobbing up and down" variant.

Out On A Limb

Literature

In Where The Sidewalk Ends by Shel Silverstein, the characters are standing on an object that is clearly about to break, and yet it somehow still supports their weight - indefinitely, since the artwork is in single-panel form, and therefore rules of cartoon physics regarding time dilation also apply.

Counterintuitive Gravity

Western Animation

Actually explained by Bugs Bunny in the short High Diving Hare. At the end of the cartoon, Yosemite Sam tries to saw off the end of a diving board, with Bugs on it. However, the diving board ladder, and part where Sam is, fall down, leaving Bugs and the end floating. Bugs remarks, "I know this defies the law of gravity but eh, I never studied law".
The Road Runner and Coyote lampshade it in one cartoon where they use signs to communicate the same thing.
In the Pink Panther cartoon Pink Outs, the Panther cuts the trunk of a sapling -- and everything including the ground drops away, leaving the top of the sapling in place as the Panther falls into a void.

↑ This does happen in the real world and is pronounced near small, dense bodies of high mass, such as black holes. In such cases it's a force more worrisome than that of eventual impact.
↑ Also true in Real Life, allowing an endless bunch of dominoes to be stacked across a room like a House of Cards, this is the principle on which Corbel vaults and Mobiles are designed. However, they must be stacked or suspended in a catenary distribution, meaning you can theoretically cantilever a pile of bricks across a ridiculously wide gap, but you get vanishing returns as the pile climbs higher
↑ This could be because It's Turtles All The Way Down.

[1] This does happen in the real world and is pronounced near small, dense bodies of high mass, such as black holes. In such cases it's a force more worrisome than that of eventual impact.

[2] Also true in Real Life, allowing an endless bunch of dominoes to be stacked across a room like a House of Cards, this is the principle on which Corbel vaults and Mobiles are designed. However, they must be stacked or suspended in a catenary distribution, meaning you can theoretically cantilever a pile of bricks across a ridiculously wide gap, but you get vanishing returns as the pile climbs higher

[3] This could be because It's Turtles All The Way Down.

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