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==Explanation==
 
==Explanation==
The {{w|James Webb Space Telescope}} (JWST) is a {{w|space telescope}} created to be the successor of the {{w|Hubble Space Telescope}} under construction at time of publishing and launched December 25, 2021, though in [[2014: JWST Delays]], xkcd predicted its launch would actually occur during late 2026.
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{{incomplete|Created by: a WAFFLE CONE MIRROR. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
  
It's implied that Cueball dropped a hammer on the mirror of the JWST and broke it. In superstition, breaking a mirror causes seven years of bad luck. The cost estimate for the JWST is currently US$10 billion, and Cueball is at a NASA official hearing for breaking this very expensive piece of equipment, no doubt costing NASA (and thus the nation) hundreds of millions of dollars more for repair work. However, Cueball is more concerned about personally experiencing seven years of bad luck.  
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The {{w|James Webb Space Telescope}} (JWST) is a {{w|space telescope}} created to be the successor of the {{w|Hubble Space Telescope}} under construction at time of publishing and expected to launch in October 2021, though in [[2014: JWST Delays]], xkcd predicted its launch would actually occur during late 2026.
  
In actuality the mirror panel is not made of glass, so it's likely that a dropped hammer would dent and distort the panel rather than shattering it. Presumably Cueball's hammer drop would damage or destroy only one mirror panel out of the JWST's eighteen panels. (If he had destroyed the entire telescope, he may have been facing 7×18=126 years of bad luck, and the damage costs would be much, much higher.  [[2153:_Effects_of_High_Altitude|Then again, this depends on the altitude that the destruction happened.]]) Even breaking a single panel would likely be very expensive because it would require extremely accurate machinery and extensive calibration tests to make and install a replacement panel, especially because the back of JWST's mirrors are made of beryllium. Beryllium is expensive to purchase, since it is relatively scarce, and is very hard and abrasive, so making things out of it is difficult (and expensive due to the specialized machinery required and the precautions necessary to prevent inhalation). Breaking a beryllium mirror would lead to dust formation; single exposures to beryllium dust [http://who.int/ipcs/publications/cicad/en/cicad32.pdf can cause] acute beryllium poisoning and massively increase the risk of lung cancer, which is very bad luck on behalf of Cueball. In addition to the property damage, Cueball is probably liable for injuring his coworkers, which is probably the main reason why the NASA workers are so angry at him because human lives are more valuable than mere money.{{Citation needed}}
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It's implied that Cueball dropped a hammer on the mirror of the JWST and broke it. In superstition, breaking a mirror causes seven years of bad luck. The cost estimate for the JWST is currently US$10 billion, and Cueball is on trial by NASA for breaking this very expensive piece of equipment, no doubt costing NASA (and thus the nation) billions more for repair work. However, Cueball is more concerned about personally experiencing seven years of bad luck.
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In actuality the mirror panel is not made of glass, so it's likely that a dropped hammer would dent and distort the panel rather than shattering it. Presumably Cueball's hammer drop would damage or destroy only one mirror panel out of the JWST's eighteen panels. (If he had destroyed the entire telescope, he would have been facing 7×18=126 years of bad luck.) Even breaking a single panel would likely be very expensive because it would require extremely accurate machinery and extensive calibration tests to make and install a replacement panel.
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While most mirrors (including telescope mirrors) are coated with silver, mercury, or another reflective gray metal in order to reflect visible light, the designers of the JWST wanted it to be able to view redshifted galaxies, requiring the mirror to reflect infrared light. While silver and most other metals are good at reflecting visible light, they are poor reflectors of infrared light. However, {{w|Relativistic_quantum_chemistry#Color_of_gold_and_caesium|relativistic effects in the electron orbitals of gold}} shift its spectral range of reflectivity to the longer infrared wavelengths desired for the JWST, and the telescope's mirror surfaces are thus made of gold. However, this gold is not a significant factor in the telescope's overall cost: the amount of gold on all the mirrors, [https://www.forbes.com/sites/startswithabang/2017/04/05/how-much-gold-is-in-the-james-webb-space-telescope about 48 grams], cost about US$2700 at the current price when this comic appeared -- a tiny fraction of JWST's overall cost.
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In addition, the back of JWST's mirrors are made of beryllium due to the light weight, stiffness, and various other mechanical properties of the metal. Beryllium is expensive to purchase, since it is relatively scarce, and is very hard and abrasive, so making things out of it is difficult (and expensive, due to the precautions necessary to prevent inhalation). Breaking a beryllium mirror would lead to dust formation; single exposures to beryllium dust [http://who.int/ipcs/publications/cicad/en/cicad32.pdf can cause] acute beryllium poisoning and massively increase the risk of lung cancer. In addition to the property damage, Cueball is probably liable for injuring his coworkers.
  
 
The title text refers to the {{w|Cold Stone Creamery}}, a chain that mixes ice cream with various other ingredients, such as fruit or candy, in front of the customer before serving it. The usual surface for mixing is a piece of granite which is kept cold (about -10°C). It's implied that Cueball had tried mixing his ice cream and flavorings in the style of Cold Stone Creamery on the JWST mirror, which is also kept cold -- in fact much colder, as it's cooled to as low as 7 K (-266°C, or -447°F). If Cueball had mixed ice cream this way on the JWST, he would likely have scratched and/or stained the surfaces on the telescope and perhaps have gotten gunk into the instrumentation, and possibly, due to the localized temperature differential from ice cream hundreds of degrees ''warmer'' than the material, promoted damaging distortions or fractures -- hardly the 'good idea' mentioned in the title text.  (It also would not have worked: at sufficiently low temperatures, ice cream hardens and cannot be mixed.)
 
The title text refers to the {{w|Cold Stone Creamery}}, a chain that mixes ice cream with various other ingredients, such as fruit or candy, in front of the customer before serving it. The usual surface for mixing is a piece of granite which is kept cold (about -10°C). It's implied that Cueball had tried mixing his ice cream and flavorings in the style of Cold Stone Creamery on the JWST mirror, which is also kept cold -- in fact much colder, as it's cooled to as low as 7 K (-266°C, or -447°F). If Cueball had mixed ice cream this way on the JWST, he would likely have scratched and/or stained the surfaces on the telescope and perhaps have gotten gunk into the instrumentation, and possibly, due to the localized temperature differential from ice cream hundreds of degrees ''warmer'' than the material, promoted damaging distortions or fractures -- hardly the 'good idea' mentioned in the title text.  (It also would not have worked: at sufficiently low temperatures, ice cream hardens and cannot be mixed.)
  
The bad luck from breaking a mirror is also referenced in [[1136: Broken Mirror]].
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The JWST has previously been mentioned in [[2014: JWST Delays]], [[1730: Starshade]], and [[1461: Payloads]].
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For some reason, the original version of this comic was very large (4332×4838px), well overflowing the boundaries of the page [https://archive.is/yJXTS]. This was probably a mistake, as the current version [https://imgs.xkcd.com/comics/hammer_incident.png] is significantly smaller at 289 × 323px.
  
 
A similar space-related hearing is shown in [[2148: Cubesat Launch]].
 
A similar space-related hearing is shown in [[2148: Cubesat Launch]].
  
 
==Transcript==
 
==Transcript==
:[Cueball, holding a palm up in front of him, stands before a long desk, behind which is a seated panel of four people, consisting of Ponytail, Hairy, a Cueball-like guy and Hairbun. Hairy is the only one to have one arm on the desk, all other arms are held down with hands below the desk.]
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{{incomplete transcript|Do NOT delete this tag too soon.}}
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:[Cueball stands before a seated panel of four people (Ponytail, Hairy, a second Cueball and Hairbun).]
 
:Cueball: Yes, I know you're mad that I dropped that hammer.
 
:Cueball: Yes, I know you're mad that I dropped that hammer.
 
:Cueball: But think about me—
 
:Cueball: But think about me—
 
:Cueball: '''''Seven years of bad luck!'''''
 
:Cueball: '''''Seven years of bad luck!'''''
 
 
:[Caption below the panel]:
 
:[Caption below the panel]:
 
:Man, NASA is really on my case about the James Webb Space Telescope.
 
:Man, NASA is really on my case about the James Webb Space Telescope.
 
==Trivia==
 
*The JWST has previously been mentioned in [[2014: JWST Delays]], [[1730: Starshade]], and [[1461: Payloads]].
 
*For some reason, the original version of this comic was very large (4332×4838px), [https://archive.is/yJXTS well overflowing the boundaries of the page]. This was probably a mistake, as the [https://imgs.xkcd.com/comics/hammer_incident.png current version] is significantly smaller at 289 × 323px.
 
  
 
{{comic discussion}}
 
{{comic discussion}}
 
 
[[Category:Comics featuring Cueball]]
 
[[Category:Comics featuring Cueball]]
 
[[Category:Comics featuring Ponytail]]
 
[[Category:Comics featuring Ponytail]]
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[[Category:Multiple Cueballs]]
 
[[Category:Multiple Cueballs]]
 
[[Category:Telescopes]]
 
[[Category:Telescopes]]
[[Category:Space probes]]
 

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