2568: Spinthariscope

2022-01-15T05:09:20Z

162.158.89.180: /* Explanation */

{{comic
| number = 2568
| date = January 14, 2022
| title = Spinthariscope
| image = spinthariscope.png
| titletext = Other high scorers are melt-in-your-hand aluminum-destroying gallium and tritium-powered glowsticks. Lawn darts are toward the other end.
}}

==Explanation==
{{incomplete|Created by a SPINTHARISCOPE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
As stated in the comic, a {{w|spinthariscope}} is a device with a small amount of radioactive material and a screen. When one of the radioactive atoms decays, it emits an {{w|alpha particle}}, which strikes the screen, which emits a small flash of light. You can see these flashes by looking through a lens.

It was invented in 1903 initially as a scientific instrument, but was soon replaced by more accurate and quantitative devices. But the original device was still popular for some time as an educational toy for children, and you can still get them today.

The joke in the comic is that most people have little understanding of radiation, and overreact to any mention that something is radioactive. So when Cueball tells Megan, White Hat, and Ponytail that the toy contains radioactive material, they're shocked and scared. But the amount of radioactive material in the toy is very tiny and the radiation is itself so trivially contained that there's practically no risk from it. The short-ranged {{w|alpha particles}} are likely stopped by the lens through which the harmless flashes of light (from particles that instead hit and neutralise in the internal screen element) are seen.

The caption says that the ratio between the assumed danger and the actual safety is the highest of any known toy. The actual safety would have to be low for that ratio to be high (while the perceived danger high), this appears to suggest that a spinthariscope would be of low safety. However the further examples given in the title text can only be understood as concerning a ratio of perceived danger to actual danger, which would render the claimed large number for the spinthariscope. Therefore the ratio described in the comic, ”apparent danger to actual safety”, is reasonably not the intended one, which instead would be “apparent danger to actual danger”.

The title text mentions some other materials/toys that sound dangerous but aren't. {{w|Gallium}} is a metallic element with a low melting point of 29.76°C (85.568°F) so it will melt in your hand. Additionally, gallium has strange properties when it interacts with aluminum, causing it to [https://www.youtube.com/watch?v=IgXNwLoS-Hw "melt"] or become brittle. {{w|Tritium}} is a radioactive isotope of hydrogen, but {{w|Tritium radioluminescence|can be used}} to create {{w|glowstick}}s and other lighted objects. Though these two materials might thus seem dangerous, they are actually typically used perfectly safely.

At the opposite end of the spectrum is {{w|lawn darts}}, a toy containing large darts that are thrown into the air to fall back down onto a target that's placed or marked upon the ground quite near the players' positions. Contrary to the spinthariscope, which sounds dangerous but is actually harmless, lawn darts sound relatively innocent but can cause severe injury if you accidentally hit a person (and a few children were even killed), so they were banned in the US in the 1980s. When sharpened, these toys even [https://www.youtube.com/watch?v=1EFAVGIylqE compare] quite favorably to weapons of war.

==Transcript==
:[Cueball, Megan, White Hat, and Ponytail standing in a line. Cueball is holding a spinthariscope. Megan has her arms bent in a defensive position. White Hat has his arms raised in fear and Ponytail is pointing at Cueball.]

:Cueball: It's a spinthariscope, a 1940s toy with a radioactive isotope inside. If you let your eyes adjust to total darkness and look into the lens, you can see the flashes of individual atoms decaying.
:Megan: What??
:White Hat: ''AAAAA!''
:Ponytail: Get it away!

:[Caption below the panel:]
:Fun fact: Spinthariscopes have the highest ratio of "that can't possibly be safe and legal" to actual safety and legality of any known toy.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Ponytail]]
[[Category:Chemistry]]
[[Category:Physics]]
[[Category:Fun fact]]

Talk:2564: Sunshield

2022-01-10T07:45:38Z

162.158.89.180:

i thought this is common knowledge. [[Special:Contributions/162.158.90.173|162.158.90.173]] 15:00, 5 January 2022 (UTC)

It's normally supposed to block sunlight from reaching the telescope. This comic turns this on its head by suggesting the telescope emits light instead of collecting it. The emitted light is claimed to outshine the sun.
The title text means that the flash is bright enough to scar the surface of Mars, which is unlikely.
[[Special:Contributions/172.68.154.143|172.68.154.143]] 15:12, 5 January 2022 (UTC)
: According to wikipedia it is about preventing heat from reaching the telescope and only secondary about the light. --[[Special:Contributions/172.68.110.139|172.68.110.139]] 15:16, 5 January 2022 (UTC)
:: The comic mentions the role of blocking light which is why I mentioned it's light-blocking property.[[Special:Contributions/172.68.154.141|172.68.154.141]] 15:34, 5 January 2022 (UTC)
::: Obviously, the comic distorts the facts to make it funny. --[[Special:Contributions/172.68.110.121|172.68.110.121]] 15:33, 5 January 2022 (UTC)
::The point of the title text is that if the flash really were bright enough to serve its purpose, it ''would'' scar the surface of Mars (when Mars happens to be in that general direction). {{unsigned|Barmar}}
:::SCAR? For the flash being bright enough, it would need to outshine supernovas. Mars would melt if not sublime. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 00:24, 6 January 2022 (UTC)
Also, the JWST is drawn here to resemble the old Polaroid Land SX-70 Instant Camera (of just about 50 years ago.) Hmmmm. "Instant" raises issues of relativistic simultaeity....
:Worse than that, shutter-click and ''then'' a flash (at least a frame of time apart) isn't that useful.
:Trigger the flash and ''then'' the shutter around the time the flash returns. Depending upon distance and depth-of-field involved (also the duration of the flash and the movement of the subjects) you might have a longer shutter-open taking in passive light ''already'', but only if you're happy mostly registering the 'bounce-back' from any given distance as the overwhelming flash gets there and back and don't mind the low amount of non-flash light leaching in, perhaps revealing motion.
:(See various planetary nebulae photos where 'shells' of illumination, from subsequent flareups in the active centre, make it look like there's shells of matter, when it's more that these are volumes of debris that were in the right place at the right time to give us the current reflected glory. It makes for interesting mind-experiments.) [[Special:Contributions/172.70.85.73|172.70.85.73]] 18:39, 5 January 2022 (UTC)
The JWST doesn't have a physical shutter, but makes a clicking sound so that it can't secretly take voyeuristic photographs of the universe.[[Special:Contributions/162.158.187.92|162.158.187.92]] 21:24, 5 January 2022 (UTC)

Searching for facts I found three comics with facts in the title, and also one other using facts like this ones Astronomy Fact. I have thus added this: [[:Category:Facts]], with [[:Category:Fun fact]] as a sub category. I have only found 5 comics so far. But where "facts" is only used a limited time, then "fact" is used more than 500 times. And the two with fact that are not in the title only used the word "fact". So if you can remember any other comic with facts that are not fun facts, then please add them to the category. As I wrote on the fact page this reminds me of the [[:Category:Tips]] under which [[:Category:Protip]] now belongs. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:48, 6 January 2022 (UTC)

I have also added all JWST comics to [[:Category:Space probes]] and wrote a bit about it in the collapsed explanation there. But may be with 6 comics (and more on the way?) it should have it's own category. What do people think about that? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:05, 6 January 2022 (UTC)
:Wait, the JWST is NOT a space probe. It is a space telescope for imaging purposes. So I disagree with putting it in that category. It already fits in the category for telescopes. [[Special:Contributions/172.70.214.43|172.70.214.43]] 19:01, 6 January 2022 (UTC)

Concerning the "click"-part in the explanation: If the JWST is using a reflex camera, the clicking noise is the mirror moving out of the way for the exposure, is producing a clicking noise far louder than a shutter mechanism and obviously happens before exposure/flashing. [[Special:Contributions/162.158.89.180|162.158.89.180]] 07:45, 10 January 2022 (UTC)

explain xkcd - User contributions [en]

2568: Spinthariscope

Talk:2564: Sunshield