explain xkcd - User contributions [en]

3029: Sun Avoidance

2024-12-26T04:40:16Z

Swalter:

{{comic
| number = 3029
| date = December 25, 2024
| title = Sun Avoidance
| image = sun_avoidance_2x.png
| imagesize = 311x403px
| noexpand = true
| titletext = C'mon, ESA Solar Orbiter team, just give the Parker probe a LITTLE nudge at aphelion. Crash it into the sun. Fulfill the dream of Icarus. It is your destiny.
}}

==Explanation==
{{incomplete|Created by a BOT FLYING TOO CLOSE TO THE SUN. Do NOT delete this tag too soon.}}
This comic shows the end of a table of human missions, both terrestrial and space-based, ranked by how far they stayed away from the {{w|Sun}}.

The vast majority of these missions have been on Earth, the Moon, or in Earth orbit, so about 157 million km from the Sun. There have also been 8 probes sent to the outer planets; they would be at the top of the list if this were shown.

Most space probes try not to get too close to the Sun, because it's extremely hot{{cn}} and their equipment (especially the electronics) are not designed to work at such temperatures and radiation levels. If they have to venture into the inner Solar System, either because the mission is to an inner planet or other body there or to use {{w|gravity assist}} of Mercury or Venus, mission planners will design the trajectory so it remains tens of millions of kilometers away from the Sun, to minimize its impact.

This comic was posted the day after December 24, 2024, when the {{w|Parker Solar Probe}} made its closest approach to the Sun. As a result, it has set a new record for the worst failure in solar avoidance. This mission needs to be really close to the Sun so it can make close-up analysis of its corona and magnetic field. It has been engineered with special solar shields to protect it from the extreme heat and radiation.

The rankings may be an “Easter egg” wherein the Parker probe’s rank of 4,303,864, if considered as a distance in miles, is equivalent to about 6.9 million kilometers. This is the expected distance from the probe to the sun for the remaining perihelions in its mission.

The next closest mission that's still in operation (the {{w|Helios (spacecraft)|Helios}} missions ended in 1985) is the {{w|European Space Agency}}'s {{w|Solar Orbiter}}. The title text jokes that it should nudge Parker so it crashes into the Sun, so the Solar Orbiter will retake the lead among missions in operation. This would be difficult, since at Parker's aphelion (furthest distance from the Sun in its orbit) it's still only about 7 million km, 35 million km from Solar Orbiter's orbit (and the probes would be much further apart if they're not on the same side of the Sun at the time). It references {{w|Icarus}}, a character from Greek mythology who flew too close to the Sun using wings crafted by his father {{w|Daedalus}}, and fell into the sea because the beeswax in the wings melted.

==Transcript==
{{incomplete transcript|There should not be a wikitable there, just do it with Transcript-style description. Do NOT delete this tag too soon.}}

:[A table with an ellipsis indicating a large number of rows being omitted, followed by seven substantive rows. All of the rank numbers except "1." are cut off at the left, with the leftmost digit being a partially cut-off "4", except that on the fourth substantive row, the "4" is shown in full with a cut-off "2" to its left. Hence, these ranks actually represent numbers with at least eight digits.]
:{| class="wikitable"
|-
!Rank
!Mission
!Sun Nearest Miss
|-
|1. . . . ... . . . 4303857.
|colspan="2"|[All other expeditions in human history]
|-
|4303858.
|Mariner-10
|69.0 million km
|-
|4303859.
|Helios 1
|46.4 million km
|-
|4303860.
|BepiColombo
|45.8 million km
|-
|24303861.
|Messenger
|45.3 million km
|-
|4303862.
|Solar Orbiter
|43.8 million km
|-
|4303863.
|Helios 2
|43.3 million km
|-
|4303864.
|Parker
|6.17 million km
|-
|}

:[Caption below the table:]
:Congratulations to the Parker Solar Probe for setting a new record for "Worst Job Avoiding the Sun."
{{comic discussion}}

[[Category:Space probes]]

3022: Making Tea

2024-12-10T06:28:59Z

Swalter:

{{comic
| number = 3022
| date = December 9, 2024
| title = Making Tea
| image = making_tea_2x.png
| imagesize = 690x291px
| noexpand = true
| titletext = No, of course we don't microwave the mug WITH the teabag in it. We microwave the teabag separately.
}}

==Explanation==
{{incomplete|Microwaved by a TEA-MAKING AUTOMATON - Do NOT delete this tag too soon.}}
Tea is exceptionally popular in the United Kingdom, to the point virtually every home has an electric tea kettle as a standard appliance. In contrast, tea is less commonplace in the United States of America (Randall's native country) and owning a separate appliance solely for tea is generally not needed. As a result, when Americans need a cup of boiled water — for tea or otherwise — it's considered normal to put the water in a microwave oven.

British people are stereotyped as taking genuine offense to microwaved water, believing it to be an objectively incorrect way to make tea. Randall mocks this stereotype through exaggeration, saying British people would be less offended by the theft of the {{w|Crown Jewels of the United Kingdom}} than they would be by a cup of microwaved water. Randall may also be referencing the story of {{w|Thomas Blood}}, who nearly succeeded in stealing some of the Crown Jewels. Shortly after his capture, he was pardoned by King Charles II and given land in Ireland worth £500 per year. If this were to reflect a pattern of behavior among British people in general, then one might believe the British view Crown Jewel theft quite positively in relation to making tea in a mug in a microwave.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

[A chart is shown with four labeled tick marks. The first two are close together on the far left side of the graph, the third is approximately in the center, and the fourth is on the far right side of the graph. Above the chart are, from top to bottom, a heading, a subheading, and a labeled arrow pointing right.]

:<big>Ways of making tea</big>
:By how angry British people get when Americans do them

:More angry

:Making it in a kettle

:Boiling water in a pot, steeping in a mug

:Making it in a chalice and ampulla stolen from the Crown Jewels

:Microwaving a mug
{{comic discussion}}

2865: The Wrong Stuff

2023-12-08T22:44:06Z

Swalter: Expanded Trojan Horse explanation to include the warriors hidden inside

{{comic
| number = 2865
| date = December 8, 2023
| title = the Wrong Stuff
| image = the_wrong_stuff_2x.png
| imagesize = 351x513px
| noexpand = true
| titletext = The phantom found Edward Everett Hale a century too early; by the time we invented satellites, the specifics of his 'brick moon' proposal were dismissed as science fiction.
}}

==Explanation==
{{incomplete|Created by a PHANTOM MATERIALS ENGINEER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Multiple times in history, there have been incidents where companies, governments, and engineers have proposed or developed plans for large vehicles composed of unconventional materials. One example is Project Habakkuk (mentioned in the comic), an aircraft carrier which was to be composed of pykrete, a mixture of wood pulp and ice. The comic imagines that all of these proposals are linked together by a single "Material Phantom," a ghost which haunts engineers and convinces them to design giant vehicles made of the "wrong materials."

The three "wrong material vehicles" mentioned in the comic are:

*{{w|The Spruce Goose}} - A {{w|flying boat}} made, in spite of its name, almost entirely out of {{w|birch}} wood. Most modern planes are constructed out of aluminum, some other metal/alloy or (partially) out of carbon / glass fibre composites (CFRC / GFRC).
*{{w|Project Habakkuk}} - An aircraft carrier composed of pykrete, a mixture of wood pulp and ice. Modern aircraft carriers are built from steel.
*{{w|Trojan Horse}} - A mythological, giant wooden horse, supposedly used by {{w|Ancient Greece|the Greeks}} to invade the city of {{w|Troy}}. Actual horses are composed, like any other animal, out of meat, bone, and miscellaneous tissues and bodily fluids. In addition, the interior of the Trojan Horse was comprised of Greek warriors rather than horse innards.

The title text references {{w|Edward Everett Hale|Edward Everett Hale's}} sci-fi novella ''{{w|The Brick Moon}},'' the first known depiction of an artificial satellite in fiction. The novella is, of course, just a sci-fi story, but the title text states that Hale was actually approached by the Material Phantom, and the novella was a serious proposal for a moon made out of bricks. Apparently, it was only retroactively perceived as science-fiction.

==Trivia==
This comic was uploaded with the "the" in "the Wrong Stuff" being entirely lowercase, breaking the normal title case used for XKCD comic titles. Possibly another word was initially intended to come before "the", in which case lowercasing "the" would be correct.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A ghost is approaching Cueball in a workshop. They are surrounded by shop equipment, such as a table with a press on it, and a small pile of what appears to be lumber. Cueball is backing away from the ghost, holding his hands up defensively.]
:Ghost: oooOOOOOOoooo Build a spaceship out of bricks! oooooOOOOOOOOoo
:Cueball: No! Go away!
:[There is a caption underneath the panel]
:The Spruce Goose, the Project Habakkuk Ice Ship, and the Trojan Horse were all work of the Material Phantom, a ghost that wanders the Earth convincing engineers to make giant vehicles out of the wrong stuff.
{{comic discussion}}