2762: Diffraction Spikes
Title text: Even if a planet is lucky enough to have a stable orbit that weaves between the spikes, the seasons get weird whenever it passes close to them.
Diffraction spikes are visual artifacts that appear to extend from light sources, mostly when viewed through a reflector telescope. In telescopes, they are often caused by the support struts of the secondary mirror in the telescope. They've become especially well known lately because they're quite prominent in images from the James Webb Space Telescope; its bigger spikes are due to the edges of the hexagonal mirror sections, not the struts.
The comic feigns that these artifacts are real spikes of stellar matter extending from the stars being viewed. The spikes have sufficient energy and coherence to slice planets that intersect them, rather than merely bludgeon or vaporize them. Additionally, they appear to nullify gravity - preventing the halves from recombining and allowing them to maintain their shape.
The title text suggests that a planet would have to be particularly lucky to avoid encountering one of these spikes during its lifetime. This would make our own solar system exceptionally fortunate, given the number of planetary bodies that remain whole, though it could perhaps serve as an explanation for the Asteroid belt, being remnants of formerly destroyed planets.
The title text also claims that the spikes produce sufficient light and heat to disrupt seasonal (and perhaps even diurnal) patterns on planets that come close enough to them, but this is not something we experience on Earth.
- [SHORT VERSION : The comic is a photo of a star, with the diffraction spikes that usually happen when taking pictures with telescopes. An exoplanet orbits that star, and its trajectory crosses one of the spikes. At the intersection point, the onomatopoeia "SLICE" is written, and the trajectory splits in two. Not far after, two half-planets continue their course.]
- [Caption below panel:]
- Bad news for exoplanets: it turns out those diffraction spikes are real.
- [LONG VERSION : On a black square background, there is a white circle, representing a star, with a diameter one-fourth the length of the background perimeter. Its center is approximately one radius left of the center of the square. Six solid white lines intersect the center of the circle, and extend into the background. Those portions of the lines that are in the background are drawn as narrow triangles; the portions within the circle (white on white) are invisible. The lines represent the rays of a diffraction pattern. The "star" drawing is bilaterally symmetrical along any of the six lines. The longest line, with the length of each ray equal to the diameter of the circle, is oriented at approximately 15/195 degrees from the vertical (left and right boundaries of the background). The second, very short, is at approximately 20 degrees. The third, fourth, and fifth, with the emergent parts approximately one radius long (the fourth slightly longer) are oriented at about 35, 50, and 80 degrees respectively. The sixth, short like the second, is at approximately 95 degrees.]
- [Near the apex of the longest line (diffraction pattern ray) at 15 degrees, there is a dashed white line, curved as if part of the circumference of a circle with radius three times that of the "star" circle, and describing approximately twenty degrees of arc. This line represents the orbit of an exoplanet circling the star. At its intersection with the diffraction pattern ray, indicated by a small white circle, the dashed line bifurcates. At the rightmost ends of the dashed lines, there are two circles, one light gray with an irregular, darker gray pattern at the center, the other white. These represent a planet that has been sliced into two equal portions by the diffraction ray. A few white specks surrounding the circles represent debris from the cutting. The word SLICE is written in white capital letters immediately to the right of the point of intersection.]
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I tried to make an initial explanation, but then someone beat me to it and I made a fool of myself on the page trying to add a comment where it didn't go. I fixed it, but I am ashamed ;~; 126.96.36.199 23:31, 12 April 2023 (UTC)
- It's all good. As long as you learn from it, and we learn what useful things you want to say, nothing at all to worry about... All power to your typing fingers! 188.8.131.52 00:15, 13 April 2023 (UTC)
Exoplanets nevertheless exist because, alongside the visible diffraction spikes that chop them up, there are invisible defraction [sic] spikes that reassemble them. 184.108.40.206 00:32, 13 April 2023 (UTC)
- Pretty sure gravity causes the pieces to drift back together. 220.127.116.11 20:33, 13 April 2023 (UTC)
- Randell actually explained this in his "What if a bowling ball would have the size of the earth?". The finger holes would instantly collapse. So if a blade would actually go through the planet there would only be local destruction and a change of momentum. 18.104.22.168 16:12, 15 April 2023 (UTC)
Why does the spike slice the planet instead of the planet breaking the tip off the spike? Are the spikes like enormous light sabers? Barmar (talk) 00:43, 13 April 2023 (UTC)
- The spikes are stellar artifacts of distant observers, with all the mass of the star behind them. The Sun hardly moves much if you dunk the Earth into it, why should the exoplanet move the spike? At best you'd get a similar effect to karate chopping a stream of water from a hose. 22.214.171.124 04:49, 13 April 2023 (UTC)
- Please stop dunking the Earth into the Sun.126.96.36.199 08:11, 14 April 2023 (UTC)
- Adding to 172.71...'s point, the spikes are made of star, so it will be incandescent gas with plasma corona. How do you "break" a gas?
Is it inspired by some movie that features this "spike pointing on some person" effect? I remember seeing one, but I don't seem to remember its name. 2659: Unreliable Connection (talk) 02:07, 13 April 2023 (UTC)
- This comic also reminded me of fractal images. 2503: Memo Spike Connector (talk) 09:06, 13 April 2023 (UTC)
- Is there also some joke here about double vision (if you cross your eyes you will see two planets), you use lens occlusion to see expolanets? (garbled)) 10:55, 14 April 2023 (UTC+1)
From an edit comment "(Refractor telescopes (using only lenses) don't give refraction spikes, reflector telescopes (using mirrors) do.)". Yeahbut, nobuf... It's just the struts, also mentioned, that are the key. You can build pure-refractor telescopes that still have struts (probably not optimal, but a design option) and therefore spikes. And you can make one with mirrors and no struts (more complicated and less of a practical shape for most mounting/launching purposes) which would therefore be spikeless. 188.8.131.52 12:00, 13 April 2023 (UTC)
- Some telescopes get diffraction spikes from the shape of the mirror. The JWST is a notable example of this. --184.108.40.206 14:13, 13 April 2023 (UTC)
- It's the sharp, angled edges that provide interference patterns (a set of "one-sided diffractions", rather than two-sided ones around an obstruction). A full round mirror on its own would not produce any spikes. Nor if the light from the edge areas cannot possibly reach the sensors, but that would mean less use of the mirror(s) they took great pains to send up there. And the secondary mirror has struts (in a Y-shape, I think, for technical reasons), thus why there's two minor spikes (actually six, but four are aligned to be hidden within the major spikes) as well as the hexagon-edge-induced set of six. Which also helps you understand in which orientation (or which two possibilities) the JWST was, in order to make any images you see from it.
- But this is already over-explained, really. You can design a mirror set to a avoid spikes, but with other technical compromises/etc. And above is correct, in that refractive telescopes can find themselves showing spikes (struts, if so designed, and other internal angles that may intrude into the light-path's edge). 220.127.116.11 17:27, 13 April 2023 (UTC)
- Diffraction spikes are also caused by window screens, dirty or scratched windscreens, and other optical blemishes. Given the relative scarcity of telescopes these are what most people have actually encountered.18.104.22.168 00:40, 15 April 2023 (UTC)
The transcript is very long... Too long : as of now, 2055 characters. That "transcript" section is intended for people who can't see the image (blind people for example), so it should be almost as fast to read as it is for you to look at the comic. There is really no need the exact angles of the diffraction spikes or anything, just a description of what's happening so that we can get the joke. You should not try to write a vectorization of the image, there are automated tools for that. 22.214.171.124 18:04, 13 April 2023 (UTC)
- The comment speaks to the difficulty of creating a transcription of an image that is meaningful to a person who cannot access the image. It would be good to hear from such folk about this.126.96.36.199 22:15, 13 April 2023 (UTC)
Why is the asteroid belt mentioned in the explanation? 188.8.131.52 19:13, 13 April 2023 (UTC)k
- If "all stars" have diffraction spikes, then there should be no planets around Sol. We exist, so Sol must be an exception to "all stars". But the asteroid belt (chopped-up planet(s)) also exists, so perhaps Sol had diffraction spikes sometime in its history. Yes, there's a real, and satisfactory, explanation for the Solar System's Jovian asteroid belt. But, context.184.108.40.206 21:58, 13 April 2023 (UTC)
I guess this refers to a solar storm predicted to go on in 2023, which does great damage to the earth's atmosphere like a spike. ClassicalGames (talk) 06:07, 14 April 2023 (UTC)
- [actual citation needed] ...are you going by solar maxima? The weak 2014 one, and the 9-14 years we can generally get between them, makes 2023 off at the earliest of expectations... Perhaps 2025 is more likely.
- And we get maybe a few days warning of "a solar storm" (CME) that might happen to come our way. Carrington Events are rare, though, and even when 3+ CMEs a day happen (slightly after sunspot maximum, and up from the low frequency of one every five days), we're such a small target that it's still more or less the same amount of total dumb-luck (15-20x a fraction of a chance with a far greater (negative) order to it). 220.127.116.11 20:42, 14 April 2023 (UTC)