3103: Exoplanet System - Revision history

1234231587678 at 02:00, 26 March 2026

2026-03-26T02:00:40Z

82.132.238.5: /* Explanation */ anthropic expectations, at the very least... We'd recognise it easier, certainly, compared to anything not based upon organic+water chemistry.

2026-03-21T16:47:54Z

‎Explanation: anthropic expectations, at the very least... We'd recognise it easier, certainly, compared to anything not based upon organic+water chemistry.

85.76.163.210: /* Explanation */

2026-03-21T10:00:03Z

‎Explanation

Ardub: /* Explanation */ Added link to 2202

2026-02-27T06:39:53Z

‎Explanation: Added link to 2202

BunsenH: NASA, we have a causality problem

2026-01-06T20:56:24Z

NASA, we have a causality problem

134.173.108.120 at 20:09, 6 January 2026

2026-01-06T20:09:20Z

2.98.65.8: /* Transcript */

2025-10-15T23:55:21Z

‎Transcript

Mathmaster at 21:57, 15 October 2025

2025-10-15T21:57:27Z

FaviFake: /* Explanation */ seems complete

2025-07-20T10:35:10Z

‎Explanation: seems complete

Cock: /* Transcript */ more explanation

2025-07-03T10:57:48Z

‎Transcript: more explanation

@@ Line 12: / Line 12: @@
 {{w|Exoplanet}}s are planets outside the Sun's {{w|Solar System}}. As astronomers discover more and more of these, they are finding all kinds of weird and unexpected examples, often with unusual and interesting physical properties, necessitating the introduction of new categorisations to describe them. Here, [[Randall]] presents a depiction of a hypothetical star system containing many exoplanets of different exotic types. Most of these are entirely imaginary, and some are outright nonsensical.
-A number of the planet descriptions reference the potential habitability. This attracts a lot of attention, particularly in the media and popular imagination, both because it suggests a higher potential for finding extraterrestrial life of a form we might more easily recognise, and because such planets might potentially be examined as candidates for future {{w|space colonization}}. Unfortunately, for many hopefuls, there are a number of specific conditions required for Earth life to survive, and there are many possible ways for space to be inhospitable to life. As a result, most exoplanets that have been discovered have conditions that make it nearly impossible for humans to survive, and difficult for any life form as we know it to exist. The examples here illustrate (in an exaggerated fashion) some of the many frustrations astronomers face when analyzing planets and getting their hopes up, only to discover the planets they found are, sadly, nothing like Earth.
+A number of the planet descriptions reference the potential habitability. This attracts a lot of attention, particularly in the media and popular imagination, both because it suggests a higher potential for finding {{w|extraterrestrial life}} of a form we might more easily recognise, and because such planets might potentially be examined as candidates for future {{w|space colonization}}. Unfortunately, for many hopefuls, there are a number of specific conditions required for {{w|Earth life|life}} to survive, and there are many possible ways for space to be inhospitable to life. As a result, most exoplanets that have been discovered have conditions that make it nearly impossible for humans to survive, and difficult for any life form as we know it to exist. The examples here illustrate (in an exaggerated fashion) some of the many frustrations astronomers face when analyzing planets and getting their hopes up, only to discover the planets they found are, sadly, nothing like Earth.
 There are a total of 19 planets in the comic. Here are the explanations for each planet, in order of how far they are from the star:
@@ Line 27: / Line 27: @@
 ; <!--175px-->  There's a pulsar here but it's probably fine
-: A {{w|pulsar}} is a {{w|neutron star}} which emits beams of radiation while spinning very fast. This means that this system is technically a {{w|binary star}}. The mass of a neutron star, this close to the visible star, means that any planets could not be simply in orbit around the latter. In addition to the {{w|gravitational instability}} this would produce, the intensity of the radiation and excess heat from the pulsar would make it extremely difficult for any form of life to exist in the system. Also, neutron stars are remnants of a {{w|Supernova}} explosion, an event which is likely to sterilize, eject, or outright destroy any planets exposed to it. All of this lends a substantial level of irony to the "probably fine" comment.
+: A {{w|pulsar}} is a {{w|neutron star}} which emits beams of radiation while spinning very fast. This means that this system is technically a {{w|binary star}}. The mass of a neutron star, this close to the visible star, means that any planets could not be simply in orbit around the latter. In addition to the {{w|gravitational instability}} this would produce, the intensity of the radiation and excess heat from the pulsar would make it extremely difficult for any form of life to exist in the system. Also, neutron stars are remnants of a {{w|supernova}} explosion, an event which is likely to sterilize, eject, or outright destroy any planets exposed to it. All of this lends a substantial level of irony to the "probably fine" comment.
 ; <!--250px-->  A waterworld paradise with beautiful oceans and warm&mdash; wait, no, we just got new measurements, it's a hellish steam oven
-: In any scientific field, new information may turn previously established knowledge on its head. Exoplanet research is no different, and a planet that at first seems to be habitable might turn out to be an incredibly deadly {{w|steam world}}. An example of this can be found in our own solar system with {{w|Venus}}, which was known to have clouds as early as the 1700s and was speculated to be habitable &mdash; but later, in the 1960s, those clouds were found to be made of steaming hot {{w|sulfuric acid}}.
+: In any scientific field, new information may turn previously established knowledge on its head. Exoplanet research is no different, and a planet that at first seems to be habitable might turn out to be an incredibly deadly {{w|steam world}}. An example of this can be found in our own solar system with {{w|Venus}}, which was known to have clouds as early as the 1700s and was speculated to be habitable &mdash; but later, in the 1960s, those clouds were found to be made of steaming hot {{w|sulfuric acid}}, at a mean temperature of 464 °C.
 ; <!--280px-->  Planet that could be habitable, if there's a form of life that hates water but loves acid and being on fire
@@ Line 76: / Line 76: @@
 : No planet, or anything other than an orbital path, shown. But apparently an indicator that all the rest of the given orbits (for Jupiter-likes, Mars-likes, dust clouds, etc., and even semi-inconvenient pulsars) exist within a planetary system that is ''extremely'' compact, fitting into a volume of space the size of that between our Sun and the orbit of its nearest planet, {{w|Mercury}}.
 : This is likely a reference to the fact that many exoplanets located so far have been in even tighter orbits around their star than Mercury is with the Sun. It is worth noting, however, that this is likely to be observational bias, as large and tightly orbiting planets have a significantly larger (and hence easier to identify) effect on their parent star. There are likely many small and more distantly orbiting exoplanets that we are simply unable to observe effectively at this time.
-: This is also likely a reference to the fact that the majority of stars in our galaxy are red dwarf stars, which are much cooler and dimmer than our Sun. This means that the habitable zone, and a suitably wide range of solar irradiance, can be found within a smaller radius of the star.
+: This is also likely a reference to the fact that the majority of stars in our galaxy are red dwarf stars, which are much cooler and dimmer than our Sun. This means that the habitable zone, and a suitably wide range of solar irradiance, can be found within a smaller radius of the star, such as the {{w|TRAPPIST-1}} system.
 : A popular subject of xkcd, the [[:Category:Firefly|Firefly]]/Serenity series has a [https://firefly.fandom.com/wiki/The_Verse fictional setting] that is ''also'' purportedly compact (by Earth's system's standards), featuring many worlds (and multiple stars, though none of them pulsars) within 'easy' in-system travelling distances for narrative purposes. Some minor inspiration may have been derived from this, though no overtly direct references appear.

@@ Line 24: / Line 24: @@
 ; <!--115px from the star-->  Planet that may actually be in the habitable zone, according to a very optimistic modeling paper by some desperate postdocs
-: The {{w|habitable zone}} of a star is the range at which water is liquid. Notably, planets in the habitable zone could potentially host extraterrestrial life, which would mean greater funding for further research. As such, researchers will go to great lengths to determine as many habitable planets as they can.
+: The {{w|habitable zone}} of a star is the range at which water is liquid. Notably, planets in the habitable zone could potentially host extraterrestrial life of a form we might more easily understand, which would mean greater funding for further research. As such, researchers will go to great lengths to determine as many habitable planets as they can.
 ; <!--175px-->  There's a pulsar here but it's probably fine

@@ Line 24: / Line 24: @@
 ; <!--115px from the star-->  Planet that may actually be in the habitable zone, according to a very optimistic modeling paper by some desperate postdocs
-: The {{w|habitable zone}} of a star is the range at which water is liquid. Notably, planets in the habitable zone are seen as options for colonization by humanity, which would mean greater funding for research. As such, researchers will go to great lengths to determine as many habitable planets as they can.
+: The {{w|habitable zone}} of a star is the range at which water is liquid. Notably, planets in the habitable zone could potentially host extraterrestrial life, which would mean greater funding for further research. As such, researchers will go to great lengths to determine as many habitable planets as they can.
 ; <!--175px-->  There's a pulsar here but it's probably fine

@@ Line 34: / Line 34: @@
 ; <!--280px-->  Planet that could be habitable, if there's a form of life that hates water but loves acid and being on fire
 : Scientists remain open to the possibility that life might form from different conditions than those found on Earth. That said, the speculation that life on this planet must "love acid and being on fire" is more than a little sarcastic. Possibly to a reference to the ''[[what if? (blog)|what if?]]'' article ''{{what if|30|Interplanetary Cessna}}'', in which Randall points out that the atmosphere on Venus is pretty survivable at 55km, except for the sulfuric acid, and way too hot at the surface.
 ; <!--300px-->  Mini Neptune

@@ Line 70: / Line 70: @@
 ; <!--745px-->  Planet whose surface may host conditions suitable for rocks
-: As with the above planet whose atmosphere "contains atoms," this planet is too difficult to get a read on, and the measurements are still so vague that it's unknown whether this planet is a rocky planet or a gas/{{w|ice giant}}.  This is also a play on the holy grail of exo-planet research — finding a planet whose surface hosts conditions suitable for ''life''. It's not impossible that that would involve [https://memory-alpha.fandom.com/wiki/Horta living rocks], but that would impose a {{w|Hypothetical types of biochemistry#Silicon biochemistry|different set of environmental restrictions}} from those for the carbon-based life we're familiar with. This may also be a reference to The Onion, which published an article titled “NASA Discovers Distant Planet With Conditions That Could Sustain Rocks”.
+: As with the above planet whose atmosphere "contains atoms," this planet is too difficult to get a read on, and the measurements are still so vague that it's unknown whether this planet is a rocky planet or a gas/{{w|ice giant}}.  This is also a play on the holy grail of exo-planet research — finding a planet whose surface hosts conditions suitable for ''life''. It's not impossible that that would involve [https://memory-alpha.fandom.com/wiki/Horta living rocks], but that would impose a {{w|Hypothetical types of biochemistry#Silicon biochemistry|different set of environmental restrictions}} from those for the carbon-based life we're familiar with. Seven months after this comic was posted, The Onion published an article titled [https://theonion.com/nasa-discovers-distant-planet-with-conditions-that-could-sustain-rocks/ "NASA Discovers Distant Planet With Conditions That Could Sustain Rocks"].
 ; <!--840px-->  Somehow this whole system is smaller than the orbit of Mercury?!

@@ Line 84: / Line 84: @@
 ==Transcript==
-{{incomplete | make little more descriptive}}
+{{incomplete transcript | make little more descriptive}}
 :[Title:]

@@ Line 84: / Line 84: @@
 ==Transcript==
-{{incomplete transcript|This transcript sucks because I used AI, but it's a start. Feel free to discard it.}}
+{{incomplete | make little more descriptive}}
 :[Title:]
@@ Line 92: / Line 91: @@
 :[Central diagram showing a star with various planets and objects orbiting around it, with trajectories connected by dotted lines and labels and descriptions by solid lines:]
-:[Label pointing to a large planet very close to the star:]
+:[Label pointing to a large planet with strips and a dot near the center close to the center:]
 :Giant planet orbiting so close that it's actually rolling on the star's surface
-:[Label pointing to a small object near the star:]
+:[Label pointing to a small object with several large bulged spots near the star:]
 :Hot Jupiter
-:[Label pointing to a small object:]
+:[Label pointing to a small object with strips on side:]
 :Mini Neptune
-:[Label pointing to a planet in the middle distance:]
+:[Label pointing to a featureless round planet in the middle distance:]
 :Planet that could be habitable, if there's a form of life that hates water but loves acid and being on fire
-:[Label pointing to another object:]
+:[Label pointing to another object with strips and a dot close to the center:]
 :Cold Jupiter
-:[Label inside a circled area:]
+:[Label inside a bounded curvy  area:]
 :Potentially habitable void
-:[Label pointing to another planet:]
+:[Label pointing to another planet with dots:]
 :Hot Mars
-:[Label pointing to a planet:]
+:[Label pointing to a featureless round planet:]
 :Planet that may actually be in the habitable zone, according to a very optimistic modeling paper by some desperate postdocs
-:[Label pointing to a medium-sized object:]
+:[Label pointing to a medium-sized object with two sets of spreading out rays coming out. There is also an outline that is slightly dotted:]
 :There's a pulsar here but it's probably fine
-:[Label pointing to another object:]
+:[Label pointing to another small featureless round planet:]
 :A waterworld paradise with beautiful oceans and warm - wait, no, we just got new measurements, it's a hellish steam oven
-:[Label pointing to a tiny object:]
+:[Label pointing to a tiny planet:]
 :Mini Pluto
@@ Line 140: / Line 139: @@
 :Lukewarm Jupiter
-:[Label pointing to a planet:]
+:[Label pointing to a planet with a line in the middle:]
 :Planet whose atmosphere is confirmed to contain atoms
-:[Label pointing to another object:]
+:[Label pointing to another object which is partly round but some parts are taken off and the parts are  shaped like rectangles:]
 :Earthlike data artifact
-:[Label pointing to another object:]
+:[Label pointing to another planet with rings and stripes, but has some small dots near the bottom of the planet and the rings:]
 :Wet Saturn
-:[Label pointing to another object:]
+:[Label pointing to another featureless round object:]
 :Either a gas giant or a fist-sized rock, depending which calibration method you use
-:[Label pointing to the second-largest object, besies the star itself. Unlike other objects, this one is not circular and has no orbit:]
+:[Label pointing to a bounded area with dots inside:]
 :Faint dust cloud that will cause several papers to be retracted
-:[Label pointing to the smallest object:]
+:[Label pointing to the a dotted line, which is outside:]
 :Somehow this whole system is smaller than the orbit of Mercury?!

← Older revision		Revision as of 10:35, 20 July 2025
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	==Explanation==		==Explanation==
−	{{incomplete\|Explanations for the planets are incomplete and some categories are missing. [[explain xkcd:Editor FAQ#table\|Do NOT create a table]], unless it is impossible to convey that information without it.}}
	{{w\|Exoplanet}}s are planets outside the Sun's {{w\|Solar System}}. As astronomers discover more and more of these, they are finding all kinds of weird and unexpected examples, often with unusual and interesting physical properties, necessitating the introduction of new categorisations to describe them. Here, [[Randall]] presents a depiction of a hypothetical star system containing many exoplanets of different exotic types. Most of these are entirely imaginary, and some are outright nonsensical.		{{w\|Exoplanet}}s are planets outside the Sun's {{w\|Solar System}}. As astronomers discover more and more of these, they are finding all kinds of weird and unexpected examples, often with unusual and interesting physical properties, necessitating the introduction of new categorisations to describe them. Here, [[Randall]] presents a depiction of a hypothetical star system containing many exoplanets of different exotic types. Most of these are entirely imaginary, and some are outright nonsensical.