3 ms·

I'm the one that made the original composite that set this whole thing off[1]! By "whole thing" I mean it's been this amazing meme-like recurring wave that's eb

by tombh 6y ago

I'm the one that made the original composite that set this whole thing off[1]! By "whole thing" I mean it's been this amazing meme-like recurring wave that's ebbed and flowed continuously in the 6 years since I made it. It's so wonderful to see. I'm not even an astronomer, I just used to like looking at Nasa's Astronomy Picture of the Day[2], which gave me the very simple idea to paste Andromeda into a picture of the moon. I'd seen a composite of the moon pasted next to Andromeda on APOD, and just wondered what it would be like the other way round. Of course my original image has been corrected many times since then by people with actual astronomy credentials. This is my favourite, corrected for both size and to be in the true colour spectrum: https://i.imgur.com/2pbfvJa.jpg https://i.imgur.com/2pbfvJa.jpg 1. https://www.reddit.com/r/spaceporn/comments/1u0dxs/andromedas_actual_size_if_it_was_brighter/ https://www.reddit.com/r/spaceporn/comments/1u0dxs/andromeda... 2. https://apod.nasa.gov/apod/astropix.html https://apod.nasa.gov/apod/astropix.html

adriand 6y ago
Beautiful. It was a great idea: congratulations on it spreading the way it has. My reaction on seeing this, probably like that of many other people, was, “wow, that would be so cool”. But of course if it looked like this normally we wouldn’t think much of it at all, just like all the other gorgeous sci-fi skies we see in movies or read about in books: multiple moons, two suns, close proximity to a ringed planet, etc. If these were our sky, they would be unremarkable. We are surrounded by incredible beauty and so rarely stop to contemplate it. But the beauty is there nonetheless. Your idea is a great reminder to pause and look up. There are deep lessons in the sky.
TheOtherHobbes 6y ago
I'm surprised no one has corrected for relative brightness. This photo would only be realistic if Andromeda was an incredibly unusual super-bright galaxy, or if we could see a lot more light. The former is physically unlikely although we'd see a very bright core if we lived next to a quasar. But the latter would turn the entire sky into a blaze of stellar glory. Far more stars would be visible, and we'd also see more nebulas between them. And other galaxies. So the entire sky would be much busier. The Moon would be blindingly bright, the Sun would be unbearable - unless we had HDR eyes and maybe protective membranes for daylight - and Andromeda wouldn't stand out as much among all the other sky candy.
- ggus 6y ago
  but we do have HDR eyes, don't we? we perceive light in a logarithmic way, we should just tune the exponent a bit more
tgb 6y ago
I also got thinking about this from APOD years ago. It's not just Andromeda that's visibly large (but too faint) to see, many famous nebulas are comparably big. The Orion nebula is over one degree across (The moon is about 1/2 degree). I'd love to a see a night sky full of all these at once and to imagine the mythologies that would have formed around them. A red-hued Mars became the god of war, what would Andromeda have been?

by tombh 6y ago

adriand 6y ago

Beautiful. It was a great idea: congratulations on it spreading the way it has. My reaction on seeing this, probably like that of many other people, was, “wow, that would be so cool”. But of course if it looked like this normally we wouldn’t think much of it at all, just like all the other gorgeous sci-fi skies we see in movies or read about in books: multiple moons, two suns, close proximity to a ringed planet, etc. If these were our sky, they would be unremarkable. We are surrounded by incredible beauty and so rarely stop to contemplate it. But the beauty is there nonetheless. Your idea is a great reminder to pause and look up. There are deep lessons in the sky.

TheOtherHobbes 6y ago

I'm surprised no one has corrected for relative brightness. This photo would only be realistic if Andromeda was an incredibly unusual super-bright galaxy, or if we could see a lot more light. The former is physically unlikely although we'd see a very bright core if we lived next to a quasar. But the latter would turn the entire sky into a blaze of stellar glory. Far more stars would be visible, and we'd also see more nebulas between them. And other galaxies. So the entire sky would be much busier. The Moon would be blindingly bright, the Sun would be unbearable - unless we had HDR eyes and maybe protective membranes for daylight - and Andromeda wouldn't stand out as much among all the other sky candy.

ggus 6y ago
but we do have HDR eyes, don't we? we perceive light in a logarithmic way, we should just tune the exponent a bit more

tgb 6y ago

I also got thinking about this from APOD years ago. It's not just Andromeda that's visibly large (but too faint) to see, many famous nebulas are comparably big. The Orion nebula is over one degree across (The moon is about 1/2 degree). I'd love to a see a night sky full of all these at once and to imagine the mythologies that would have formed around them. A red-hued Mars became the god of war, what would Andromeda have been?