3103: Exoplanet System

2025-06-17T03:17:00Z

2607:FB90:EC01:1185:A0E9:232D:A91D:2C1C: Planet whose atmosphere...

{{comic
| number = 3103
| date = June 16, 2025
| title = Exoplanet System
| image = exoplanet_system_2x.png
| imagesize = 623x447px
| noexpand = true
| titletext = Sure, this exoplanet we discovered may seem hostile to life, but our calculations suggest it's actually in the accretion disc's habitable zone.
}}

==Explanation==
{{incomplete|Explanations for the planets 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 Solar System. Astronomers are constantly on the look for planets that have Earth-like conditions, especially Earth-like planets that might support life. Unfortunately for many hopefuls, the conditions that made Earth suitable for life are believed to be extremely rare. Randall draws a hypothetical star system containing many exoplanets that describe (in an exaggerated fashion) 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.

Here are the explanations for each planet, in order of how far they are from the star:

# '''Giant planet orbiting so close that it's actually rolling on the star's surface'''
#: Giant planets are often gravitationally pulled close to their star. Here, the planet is literally touching the star, which, given both bodies' gaseous makeup, should cause them to merge.
# '''Hot Jupiter'''
#: A {{w|Hot Jupiter}} is typical terminology used in analyzing exoplanets, generally depicting a gas giant (of a size similar to our Jupiter or Saturn) which orbits in a much closer/hotter orbit than our own. Hot Jupiters are easier to detect than many other types of exoplanets, due to their gravitational effect on their stars.
# '''Planet that may actually be in the habitable zone, according to a very optimistic modeling paper by some desperate postdocs'''
#: The 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.
# '''There's a pulsar here but it's probably fine'''
#: A pulsar is a neutron star, emitting beams of radiation while spinning very fast. Contrary to the label, presence of a neutron star in the system is probably not fine, since a second star would be source of gravitational instability, a lot of extra heat, and the beams of radiation pose substantial danger to the planets, rendering their surface uninhabitable. It also means, that this system is technically a binary star
# '''A waterworld paradise with beautiful oceans and warm— 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 which at first seems to be habitable might turn out to be incredibly deadly.
# '''Planet that could be habitable, if there's a form of life that hates water but loves acid and being on fire'''
#: Possibly to a reference to [https://what-if.xkcd.com/30/ What-If #30], 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.
# '''Mini Neptune'''
#: "Jupiter" and "Neptune" are rough size/mass categories for gas giants with a mass similar to Jupiter versus Neptune/Uranus. A mini Neptune would be smaller than Neptune, possibly small enough not to be a gas giant at all.
# '''Lukewarm Jupiter'''
#: A humorous extrapolation of Hot Jupiters, assuming that there are other named types of Jupiters.
# '''Planet whose atmosphere is confirmed to contain atoms'''
#: With interstellar distances, it is inevitable that some planets will be hard to get a read on. Here, the astronomers can only confirm the planet has an atmosphere, not what it is made of or how thick it is. Possibly in reference to headlines about exoplanets whose atmospheres contain molecules that may indicate biological life, but extrapolated to comedic levels of vagueness.
# '''Earthlike data artifact'''
#: An {{w|Artifact (error)|artifact}} in this context is any error where it looks like something exists when it actually doesn't. This is usually caused by faults in the equipment. In this case the astronomers thought they detected an Earth-like planet, only to discover it was a data artifact.
# '''Cold Jupiter'''
#: Implicitly the opposite of a "Hot Jupiter" described above. Used here as another extension of the "Hot Jupiters" running gag, "Cold Jupiters" is occasionally used in real astronomy but is fairly informal.
# '''Potentially habitable void'''
#: It seems that the ideal orbital distance for habitable planetary conditions does not actually contain any planets, to the implied frustration of the astronomers.
# '''Hot Mars'''
#:Continuing the joke on Hot Jupiter. This assumes that if there's hot Jupiters, there must be a "hot" variant of every planet.
# '''Faint dust cloud that will cause several papers to be retracted'''
#: This could refer to either Fomalhaut b, aformer proposed exoplanet that turned out to be a dust cloud, or Tabby's Star, a star with odd irregular dimming pattern likely due to a dust cloud which was briefly thought by some to be an alien megastructure.{{acn}}
# '''Either a gas giant or a fist-sized rock, depending upon which calibration method you use'''
#:Even if a "fist-sized rock" were detectable around a distant star (it would be difficult to spot {{w|Russell's teapot|something of this size}} around ''our own'' star), this represents a considerable range of uncertainty between tens of thousands of kilometres and a few centimetres, being perhaps five orders of magnitude. This is not particularly accurate, even for a [[2205: Types of Approximation|cosmologist]].
# '''Mini Pluto'''
#:Pluto is already significantly smaller than most planets, thus its designation as a "dwarf planet". A "mini Pluto" suggests an exoplanet that shares most of Pluto's features, but is somehow ''even smaller''.
# '''Wet Saturn'''
#: May be a reference to the 'fact' that "Saturn would float in water" {{w|Saturn#Physical characteristics|due to its density}}. The difficulties of finding a practical way to test this out, notwithstanding, perhaps someone managed it with this planet.
# '''Planet whose surface may host conditions suitable for rocks'''
#: As with planet number 9, this planet is too difficult to get a read on, and the measurements are still so vague it's still unknown if this planet is a rocky planet or a gas/ice giant.
# '''Somehow this whole system is smaller than the orbit of Mercury?!'''
#: 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 solar system that is ''extremely'' compact.
; Title text
: The title text mentions a planet within an accretion disk, which means that the planet is in the orbit of a black hole and will bombarded with X-rays and stars orbiting at close range. Nevertheless, the researcher speaking assures that the planet is in the disk's habitable zone, implying it is a worthwhile option for colonization.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

{{comic discussion}}<noinclude>
[[Category:Astronomy]]

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3103: Exoplanet System