This is the third comic in the Stargazing series. The first 1644: Stargazing appeared four years earlier and the second 2017: Stargazing 2 one and a half years earlier.
As in the first two comics Megan is a TV host who continues mixing accurate astronomical information with trivialities, as well as utterly bizarre statements. (See this section from the original Stargazing comic about the host and also the trivia, from the original comic, regarding the gender of the host).
Vega is a star in the constellation of Lyra. It does indeed have magnitude 0.03 and is the brightest star mentioned in this comic. Vega is only the 5th brightest star (outside of the Sun), as Sirius is the brightest visible star. The phrase
It's the brightest star I'm currently talking about is an example of the technically correct but not at all useful information that is typical of the Stargazing series. The phrase is true no matter what, because any star one talks about is the brightest star one is talking about, as any brighter star becomes the one talked about when mentioned.
Polaris is indeed the star over the North Pole, and is commonly called the North Star or the Pole Star. It is the brightest star in the constellation Ursa Minor, but there are about fifty other stars that are as bright as it is (magnitude 2), so it's not really remarkable apart from being the pole star, as Megan says. Despite the fact that being the pole star is "all it has going for it," it is nevertheless very important because it is used for navigation, as it appears fixed in the night sky. It hasn't always been and won't always be the pole star, however, as Earth's axis precesses in a 26,000 year cycle.
Comets are comparatively small clumps of rock and ice, seen mostly by the long, lit 'trail' of particles the heat of the sun causes to be ejected, and the solar wind then spreads outward in thin glowing lines that can be larger and more visible even than the constellations they are seen in front of - at least during the brief phase of their closest approach to the sun. Comets generally have highly elliptical orbits around the Sun and so they are only seen for a brief period of time "every few decades" during their closest aproach. Yelling at comets is believed to be an ineffective way to make them go away. Megan may dislike comets because of their history in superstition of being seen as a sign of doom. This provides humor because typically this superstitious fear was caused by a lack of understanding, and it would be expected that a stargazing host would be informed on and therefore unafraid of comets. No actual astronomers are bothered by comets, but some are upset about satellite megaconstellations such as SpaceX's Starlink. In that case, astronomers are not yelling at the satellites, but at the companies that launch them.
Light pollution is indeed a problem with stargazing. Light pollution is the presence of artificial light in the night sky, which makes it very difficult to see stars. Stargazing in remote locations is remarkably different than in populated cities. Light pollution was previously discussed in 2121: Light Pollution. Light pollution does not actually make the "sky go away", but it does affect how humans can see stars or other astronomical features in the sky.
Megan advocates an active approach to resolving light pollution—rather than lobbying for reductions in artificial lighting, as the dark-sky movement does, she intends to lead her audience in destroying artificial lights. Older lightbulbs are usually glass bulbs filled with inert gas (for incandescent bulbs) or high-pressure gases (for e.g. sodium-vapor lamps) and so are easy to destroy with any blunt impact, thus accounting for Megan's mention of "throwing rocks at them". Modern LED lights, however, are much more robust, which is why she is handing out crossbows to achieve greater projectile energy. An "astronomy crossbow" is a tool used to measure the angular distance between stars. They cannot shoot real crossbow bolts, but any type of crossbow or other weapon could be used to destroy lights and "preserve" the sky. (Speaking of astronomy tools that have weapon-related names, there is a type of telescope called a "Sun Gun", but it is only meant to be used during the day to enable groups of people to view the Sun safely. It is probably best that Megan's show is taking place at night, or else she might cause even more trouble.)
In the title text Megan mentions that by destroying enough of the lights in the region will make it possible to see more comets. By reducing the light pollution it will in general be possible to see more of any kind of astronomical objects, not just comets. But as Megan has made clear she dislikes comets, and is thus not interested in seeing any of them. But to see more of any of the other astronomical objects out there, she is willing to take the risk of seeing more comets, by lowering the light pollution.
- [In a dark panel, Megan as a TV host stands in front of a group of people: Science Girl, Ponytail and Cueball. The panel is inverse-colored, i.e. white text and drawings on black]
- Host: Welcome back to Stargazing.
- Host: There are no new stars since last time, but you came back for some reason.
- [Zoomed out on the same scene, the host is now with Science Girl, Ponytail, Cueball, a Megan-like woman, and White Hat. The host is pointing upwards with her left hand.]
- Host: That star is Vega. At magnitude 0.03, it's the brightest star I'm currently talking about.
- Host: That one is Polaris. It's over the North Pole, which is all it has going for it.
- [A frame-less white panel, zoomed in on the host, who is now pointing upwards with her right hand.]
- Host: That's a comet. Some of them come back every few decades, no matter how much I yell at them.
- Host: But stargazing isn't all fun yelling. We face a problem even worse than comets: light pollution.
- [Back to a dark panel, the host now has a big bag of crossbows. The bag has a logo of a crossbow with stars around it. She has taken out one of them and is holding it in her right hand.]
- Host: The sky is going away because people keep shining lights at it. The new LEDs are even worse - they're too blue, and you can't turn them off by throwing rocks at them like with the old ones.
- Host: Luckily, I brought these astronomy crossbows.
- Host: Take one, then let's fan out and look for lamps.
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I think the "you can't turn them off by throwing rocks at them like the old ones" is a reference to a reddit comment in a thread about older generations refusing to learn new technology, or something to that extent. One comment detailed a humorous story wherein they had been helping a village install electricity/light bulbs, and this grandmother of the household kept shattering all the bulbs by throwing rocks at them to turn them off, refusing to learn how to use them correctly. I'm trying to search for this, but no luck so far. If this was not a reference to that thread but merely a coincidence, my apologies for making you read all of this. Wigglebeans (talk) 20:55, 28 February 2020 (UTC)wigglebeans
- I remember that comment as well. I feel like it was in ask reddit, but I can't seem to find it either. 18.104.22.168 23:15, 28 February 2020 (UTC)
- ExplainXKCD is the strangest, most extreme example of absurd apophenia, with people regularly picking out some overly specific and unlikely parallel from their own person experience, and claiming that's the clear origin of a given comic. « Kazvorpal (talk) 21:19, 3 March 2020 (UTC)
Can someone make a category for the Stargazing series? 1644: Stargazing, 2017: Stargazing 2, and this one. 22.214.171.124 23:29, 28 February 2020 (UTC)
- Oh, nevermind, it already exists: Category:Stargazing 126.96.36.199 23:31, 28 February 2020 (UTC)
Actually, "no new stars being created" is not just not obvious, it would need grant, research and citation. I mean, sure, actually new star (and not just star which started to be more luminous like nova) don't appear that often, and one visible by naked eye even less so, but it still CAN happen - and can easily be overlooked. The estimate is that seven new stars are formed in our galaxy every year. -- Hkmaly (talk) 23:36, 28 February 2020 (UTC)
Astronomy crossbows are real things. They are used to measure the angular distance between stars. Here's a fancy one (used) for sale for $700,  and here is a simple one that is simply a yardstick pulled back into a curve and stuck on the end of a stick . Rtanenbaum (talk) 23:51, 28 February 2020 (UTC)
I've got one of those expensive crossbows from Gregg Blandin. It's an equatorial platform that allows a simple dobsonian telescope to track the stars. It has nothing to do with measuring angular distances. So I changed the link to the astronomy course that uses the simple type to measure angular distances. Johnrb (talk) 04:14, 29 February 2020 (UTC)
I wonder if the title text is a Shrek reference? It follows the same basic structure of the some of you may die meme. Moosenonny10 (talk) 14:39, 29 February 2020 (UTC)
At the moment (or at least over the last several nights, right now the biggest illumination in the sky for me is the overcast but daylight sky itself) the most obviously brightest 'star' in the sky is Venus, fairly close to the (even more bright, far less apparently star-like) crescent Moon. As our guide to the stars does not mention Venus, this does not in any way invalidate the brightness statement; even without taking true-stellarity of a "Fool's Star" into account. And, for all we know the presentation is being given at a local time when Moon+Venus are not visible above the horizon anyway. But worth noting, perhaps. As is that neither rocks nor crossbow are likely going to be trivially useful in extinguishing daylight, moonlight or Venus (nb: these three not necessaily listed in order of difficulty, in the event you wish to try to!) 188.8.131.52 17:25, 29 February 2020 (UTC)
The title text is not saying that new comers would be created; I believe that's an inference someone made. It just discussed the risk of SEEING more comets. Momerath (talk) 11:44, 1 March 2020 (UTC)
- I think it's a probable inference, though. Reverse-Astrology: What happens on Earth changes the progresson of the heavens. Well, apart from yelling - and so far there's no indication that it either discourages them nor attracts them, though every time you see a new one you have to wonder if they've come to see what the fuss is all about...
- Reverse Astrology would be made easy with a Nicoll-Dyson beam and a few mirrors. Just move the stars / planets into the correct position... 184.108.40.206 19:04, 2 March 2020 (UTC)
220.127.116.11 17:33, 1 March 2020 (UTC)
- (Additional: It is of course well known that yelling at the winter-solstice Sun is a reliable way of making sure it gets over its disinclination and starts rising higher again for the next part of the year. Hasn't failed yet! (And wouldn't be necessary to repeat if it weren't for Aussie yellers, I'm sure.) I didn't actually yell at the eclipsing Sun the handful of times I've seen that happening, but I've seen on TV that others did it for me (fortunately), just as I'll gladly help you out at midwinter.) 18.104.22.168 17:44, 1 March 2020 (UTC)
The joke appears to be someone confusing seeing more comets (which already exist) with believing more comets exist now because they can see them. 22.214.171.124 17:24, 2 March 2020 (UTC)wigglebeans
"They're too blue" line needs to be properly explained. From looking at Wikipedia, many LEDs are blue, and blue light affects light pollution higher than the warmer colors, for essentially the same reasons that the sky itself is blue (blue light scatters easily by the atmosphere). 126.96.36.199 14:18, 3 March 2020 (UTC)
- It's not just the disserpation of the blue light, that makes for worse lights than some traditional street-lighting. "White" LEDs are either Red+Green(/YellowGreen)+Blue (made possible since the development of a bright-enough Blue LED to make this easy enough) that when all displayed come through our visual system as high-temperature whiteness, or they are monochromatic (maybe blue, maybe UV) but housed upon a phosphor (the often-yellow sliver(s), larger than than the obvious electronic elements, that can be seen when examining an inactived unit).
- The trichromatic method (useful in 'tunable' lights, that can be cycled through hues) has sharp spikes of colour, so some optical astronomy that is interested in spectral areas outside of those bands might still be conducted by filtering the annoyance. The smeared-spectrum of the phosphorised light (when you don't care about anything other than the white light being on or off) is more of a problem.
- And also LED streetlights tend to be perceptually (if not actually) brighter than their pre-LED versions. They're often made to shine downwards into a smaller footprint(though this concentration and contrast creates noticably darker areas between the bright focii of the row of lamps, in my experience) but of course the lit ground/etc then 'shines' upwards again.
- About the best you can say is that they aren't actually primarily aimed upwards and outwards like your average Batsignal/Luxor searchlight, but it seems to me that any hint of cloud over/near a modern city is now even more awkward when it comes to searching for stars than it was when it only precipitated an amber glow through which a given degree of stellar pinprickery could still sometimes be observed. 188.8.131.52 20:22, 4 March 2020 (UTC)