Talk:3066: Cosmic Distance Calibration
yay. DollarStoreBa'al (talk) 16:31, 21 March 2025 (UTC)
What makes such labels as real objects absurd is not the required size, but the required orientation to be readable from a single point in the universe - earth. 172.71.154.9 19:26, 21 March 2025 (UTC)
- All facing towards us AND all the right way up! That's geographically unlikely. ;-) Robert Carnegie [email protected] 172.71.178.157 10:11, 22 March 2025 (UTC)
A straightforward application of the Anthropic principle. 104.23.187.189 19:35, 21 March 2025 (UTC)
I'm not sure I get the title text... 162.158.62.162 20:04, 21 March 2025 (UTC)
I like this part of the linked article: But cosmologists get only one universe to observe. -- Hkmaly (talk) 20:09, 21 March 2025 (UTC)
I think that the crosshairs in question are markers to indicate which star is being labeled, not anything to do with video games. 162.158.137.59 23:46, 21 March 2025 (UTC)
- That's my suspicion as well: just markers like the labels, not diffraction spikes or anything like that. BunsenH (talk) 03:41, 22 March 2025 (UTC)
The crosshairs are all the same size because new red giant stars are all the same brightness. They are "TRGB" or "Tip of the Red Giant Branch" standard candles. Every star in that phase of evolution is exactly the same absolute brightness, so we can tell how far away it is by measuring the observed luminosity. 162.158.212.132 00:35, 22 March 2025 (UTC)
2035: Dark Matter Candidates also hypothesizes that astronomical labels are physically there, the orbit paths in this case. Should it be added? Intara (talk) 00:43, 22 March 2025 (UTC)
OH MY GOD! Why are there two blue boxes saying we need to complete 58 explanations? I would suggest that just one would be less distracting/disruptive. 172.68.2.70 03:19, 22 March 2025 (UTC)
- Perhaps one box wasn't enough... although it seems reasonable to have an increasing number of cartoons that nobody felt able to explain. Robert Carnegie [email protected] 172.70.91.29 10:15, 22 March 2025 (UTC)
Regarding the crosshairs: TBH, I don't think the comic refers to diffraction patterns/spikes. I think it simply refers to literal crosshairs, as in "some stars are marked with crosshairs in this image and the astronomers think those crosshairs are some kind of real, physical phenomena". See the comic itself for an example of such a crosshair (the zoomed star has one!). --172.68.7.138 05:39, 22 March 2025 (UTC)
- After noticing that other comments in this discussion page mentioned the same as I did, I took the liberty to update the text. --172.68.12.34 05:48, 22 March 2025 (UTC)
This comic seems extra ironic, given that NASA has been grossly misreporting the distances to extremely distant objects lately, due to lack of adjustment for observed differences in spacetime, in order to express things "simply". Most people of course don't care & those using more reliable resources are unaffected, but hobbyists & reporters etc are going "Wait, what? Those numbers are way off..." ProphetZarquon (talk) 14:16, 22 March 2025 (UTC)
There's surely no problem with stars having labels that look like they are to be read only by us, at our distance (and at this time). All each star needs to do is to send out highly-directional flashes (relatively, at least!) of light, such that the ones that will arrive at Earth around now were projecting information suitable for us back then, but light arriving at stars five hundred years ago, at a similar distance on a perpendicular track, will feature suitable information shone out five hundred years earlier (while sending vaguely in this direction only information destined to be useful for the star 'between' us, five hundred light-years in that direction). I'm sure you can appreciate how simple it is to accomplish this, all you need to do is have different patterns of photos continually travelling out in different sectros of different shells of ever-changing light, out into the universe, all ready to convey exactly the right information to the observer who happens to eventually be where the light gets observed, inexactly the right orientation and notation/language, as well! Simple! 172.68.205.92 22:58, 23 March 2025 (UTC)
Holograms are a thing, people. A different label could be aimed at each viewer. Heck, there might only be one viewer at present. And who said the labels are made of matter? This is the worst explanation page I have ever seen here. 172.68.54.235 11:43, 24 March 2025 (UTC)
- Though holograms don't just appear 'in thin air' (or, indeed, vacuum). You're either looking at a medium imprinted with a clever diffraction patterns to shape the intensity of light projected out in various directions, or illuminating an amorphous media with precisely targeted light (e.g. lasers in a very mildly misty atmosphere, so that only where you have the brightest lines of laser, or the convergence of two or more less obvious beams, do you get omnidirectionally visible lines/areas/voxels) to produce an apparent object.
- If you could always just magic up photons out of nowhere, you could have them appear (with the qualities required of them as if they had come from a star-adjacent emiter) in the last few light-years, or indeed light-seconds, in the middle of space heading exactly in the right direction (in exactly the right configuration) to be seen by your telescope. But that's getting towards God-tier 'causality'-bending. 172.69.43.241 11:59, 24 March 2025 (UTC)
