explain xkcd - User contributions [en]

3111: Artificial Gravity

2025-07-05T04:03:42Z

2600:1700:94A0:6BE0:305E:B9B8:99C0:481F: /* Explanation */

{{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==
{{incomplete|This page was created BY NASA. Don't remove this notice too soon.}}
The human body will experience slow but adverse side effects in a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage. Many prototype designs have been introduced to combat this, both in science fiction and real life, and one of the most common (for non-fictional purposes, or in {{w|hard science fiction}}) is to use inertia and [[123: Centrifugal Force|centripetal force]] to simulate the effects of gravity on the crew.

[[Cueball]] describes a spacecraft in which the crew quarters are being continuously shaken. [[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 — a common sight in speculative (yet 'hard science') spaceship designs. Cueball concedes his agreement, but states that the crew is already stuck with the shaking-pod setup, implying the ship has already been built, launched, and is in operation.

The title text discusses a real side effect of low gravity environments: a form of bone density loss known as {{w|Spaceflight osteopenia}}. The title text 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 centripetal force has done anything to reduce bone 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.]
: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]]

3111: Artificial Gravity

2025-07-04T18:03:06Z

2600:1700:94A0:6BE0:305E:B9B8:99C0:481F: /* Explanation */

{{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==
{{incomplete|This page was created BY NASA. Don't remove this notice too soon.}}
The human body will experience slow but adverse side effects in a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage. Many prototype designs have been introduced to combat this, both in science fiction and real life, and one of the most common is to use inertia and centrifugal force to simulate the effects of gravity on the crew.

Cueball introduces a design where the crew quarters are a large shaking pod. 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 — a common sight in speculative spaceship designs. Cueball concedes his agreement, but claims the crew are going to be stuck with shaking pod design anyway. In fact he reveals that the plans are not in the design stage as was implied, but that the ship has already been built and launched, and Ponytail's fears about the design are already being demonstrated.

The title text discusses a real side effect of low gravity environments: a form of boss density loss known as {{w|Spaceflight osteopenia}}. The title text 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 breaking the crew members' bones. The broken pieces of bone are then being counted as separate bones.

==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.]
: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]]

3111: Artificial Gravity

2025-07-04T18:01:28Z

2600:1700:94A0:6BE0:305E:B9B8:99C0:481F: /* Explanation */

{{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==
{{incomplete|This page was created BY NASA. Don't remove this notice too soon.}}
The human body will experience slow but adverse side effects in a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage. Many prototype designs have been introduced to combat this, both in science fiction and real life, and one of the most common is to use inertia and centrifugal force to simulate the effects of gravity on the crew.

Cueball introduces a design where the crew quarters are a large shaking pod. 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 — a common sight in speculative spaceship designs. Cueball concedes his agreement, but claims the crew are going to be stuck with shaking pod design anyway. In fact he reveals that the plans are not in the design stage as was implied, but that the ship has already been built and launched, and Ponytail's fears about the design are already being demonstrated.

The title text mentions that "the number of bones in each crew member has been steadily increasing" - this is because the shaking, and subsequent multiple impacts, are breaking the crew members' bones. The broken pieces of bone are then being counted as separate bones.

==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.]
: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]]

3111: Artificial Gravity

2025-07-04T17:51:34Z

2600:1700:94A0:6BE0:305E:B9B8:99C0:481F: /* Explanation */

{{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==
{{incomplete|This page was created BY NASA. Don't remove this notice too soon.}}
The human body will experience slow but adverse side effects in a low gravity environment, such as a spaceship taking an interplanetary or interstellar voyage. Many prototype designs have been introduced to combat this, both in science fiction and real life, and one of the most common is to use inertia and centrifugal force to simulate the effects of gravity on the crew.

Cueball introduces a design where the crew quarters are a large shaking pod. 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 — a common sight in speculative spaceship designs. Cueballs concedes his agreement, but claims the crew are going to be stuck with shaking pod design anyway.

==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.]
: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]]