Editing 3111: Artificial Gravity

{{comic
| number    = 3111
| date      = July 4, 2025
| title     = Artificial Gravity
| image     = artificial_gravity_2x.png
| imagesize = 423x365px
| noexpand  = true
| titletext = Low gravity can cause bone loss, so we're pleased to report that, since we initiated capsule motion, the number of bones in each crew member has been steadily increasing.
}}

==Explanation==
In a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage, the human body will experience slow but {{w|Effect_of_spaceflight_on_the_human_body|adverse side effects}}. Many prototype designs have been introduced to combat this, both in science fiction and real life. One of the most common (for non-fictional purposes, or in {{w|hard science fiction}}) is to use a rotating system to subject the crew to [[123: Centrifugal Force|centrifugal force]], simulating the effects of {{w|gravity}}. Examples of mimicking gravity using spinning elements are: the whole wheel-like space-station and internal living ring of the ''Discovery'', from ''{{w|2001: A Space Odyssey}}'';  the extended rotating arms of the ''Hermes'', in ''{{w|The Martian (film)|The Martian}}''; the whole rotating structure of ''Endurance'', from the movie ''{{w|Interstellar (film)|Interstellar}}''.

[[Cueball]] instead describes a spacecraft in which the crew quarters are being continuously shaken back and forth across an axis. [[Ponytail]] immediately sees problems with this approach, and asks if the shaking pod can be replaced with a much safer and more stable spinning wheel or cylinder. Cueball concedes this argument, but reveals that the ship has already been built, launched, and is in operation, so the crew is stuck with the shaking pod setup. Apparently, nobody pointed out that there was a much better approach during the mission development.

A shaking spaceship design would create an experience of gravity for the crew — just a very unpleasant one. When the capsule accelerates "up" (from the point of view of the picture), the crew will feel a gravity-like force pulling them "down" against the capsule 'floor'. However when the capsule accelerates "down", the crew will find themselves thrown against what was the 'ceiling' of the capsule, but has now suddenly become the 'floor', in an experience similar to falling several metres. The direction of this artificial "gravity" will keep alternating as long as the capsule keeps shaking. This will result in the crew not only repeatedly falling against one surface or the other, but also at a variable apparent gravity as the capsule's lateral velocity changes. This might make their life onboard ship, which could (otherwise) be expected to last for many years, somewhat unpleasant.

This shaking system would also be wasteful of energy, since there would be losses due to friction at the joints between modules, as well as the energy costs of changing the motion of the crew module relative to the rest of the structure. In contrast, a rotating structure freely floating in a weightless environment tends to retain its motion, with negligible losses due to interactions with other bodies.

The title text discusses the form of bone density loss known as {{w|spaceflight osteopenia}}, caused by gravity loss. The speaker claims that "the number of bones in each crew member has been steadily increasing". This is because the shaking, and subsequent multiple impacts, are fragmenting the crew members' bones. The broken pieces of bone are then being counted as bones in their own right and increasing the effective count, without telling if the pod's awkward configuration has done anything to reduce bone ''mass'' loss.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
:[Cueball and Ponytail are standing near a blueprint of a spacecraft, with Cueball pointing at the blueprint. In place of conventional conical fairing, this spacecraft has a large mechanical arm on the nose. The arm is holding an egg-shaped capsule. Two semi-transparent drawings of the arm and the capsule are depicted on either side of it with speed streaks in between, implying shaking back and forth motion of the arm.]
:Cueball: To produce artificial gravity during the voyage, the crew capsule is kept in constant motion.
:Ponytail: Wouldn't it make more sense to spin it instead of shaking it, so the acceleration is steadier?
:Cueball: ...Listen. You, I, and the crew all wish we'd thought of that before launch.

{{comic discussion}}<noinclude>

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Space]]