Eise Posted April 21, 2019 Share Posted April 21, 2019 (edited) Comment not needed... The article is here. Do not forget to follow this link (from the article) for the zoomable version. What are all these ring structures? I thought planetary nebulae do not exist that long, so to see so many seems impossible. But what else are they? Edited April 21, 2019 by Eise 2 Link to comment Share on other sites More sharing options...
beecee Posted April 21, 2019 Share Posted April 21, 2019 3 hours ago, Eise said: Comment not needed... The article is here. Do not forget to follow this link (from the article) for the zoomable version. What are all these ring structures? I thought planetary nebulae do not exist that long, so to see so many seems impossible. But what else are they? Perhaps the tidal interactions with the Milky Way galaxy and the SMC have prompted in the past, a period of stellar formation and we now see that with the result of supernova or red giants that have become White Dwarfs after blowing off their outer layers. Link to comment Share on other sites More sharing options...
Eise Posted April 22, 2019 Author Share Posted April 22, 2019 13 hours ago, beecee said: Perhaps the tidal interactions with the Milky Way galaxy and the SMC have prompted in the past, a period of stellar formation and we now see that with the result of supernova or red giants that have become White Dwarfs after blowing off their outer layers. From Wikipedia: Quote They are a relatively short-lived phenomenon, lasting perhaps a few tens of thousands of years, compared to a considerably longer phases of stellar evolution. Even if you are right, if there once was a star burst time, several billions of years ago, were there so many stars with about the same lifetime (~ starting mass), that happened to blow up alltogether right now? Maybe, but it seems a bit unlikely to me. I would be happy to hear some more (scientifically based!) speculations that explain this multitude of planetary nebulae, or a complete different explanation of what these rings are. Link to comment Share on other sites More sharing options...
MigL Posted April 22, 2019 Share Posted April 22, 2019 I don't have a clue, Eise. But that is a lovely photo. Link to comment Share on other sites More sharing options...
koti Posted April 22, 2019 Share Posted April 22, 2019 I was ready to complain that they took the photo with a crappy sensor untill I zoomed in and discovered that the grain is actually more stars and galaxies. Stunning. Link to comment Share on other sites More sharing options...
michel123456 Posted April 22, 2019 Share Posted April 22, 2019 On 4/21/2019 at 8:56 PM, Eise said: What are all these ring structures? I thought planetary nebulae do not exist that long, so to see so many seems impossible. But what else are they? What is your problem with that? what do you mean with "do not exist that long"? Link to comment Share on other sites More sharing options...
koti Posted April 22, 2019 Share Posted April 22, 2019 (edited) 35 minutes ago, michel123456 said: What is your problem with that? what do you mean with "do not exist that long"? Distance and the speed of light. If we see something from Earth and its a million light years away, we see that thing how it was a million years ago. If things exist only for a few hundred thousand years and they are hundreds of million light years appart in distance from each other you shouldn’t be able to see them at the same time on Earth. Edited April 22, 2019 by koti Link to comment Share on other sites More sharing options...
michel123456 Posted April 22, 2019 Share Posted April 22, 2019 3 minutes ago, koti said: Distance and the speed of light. If we see something from Earth and its a million light years away, we see that thing how it was a million years ago. If things exist only for a few hundred thousand years and they are hundreds of million light years appart in distance from each other you shouldn’t be able to see them at the same time on Earth. Right, but I read that the Large Magellanic Cloud is ≈163,000 light-years away. That leaves plenty of time. Link to comment Share on other sites More sharing options...
Janus Posted April 22, 2019 Share Posted April 22, 2019 1 hour ago, koti said: Distance and the speed of light. If we see something from Earth and its a million light years away, we see that thing how it was a million years ago. If things exist only for a few hundred thousand years and they are hundreds of million light years appart in distance from each other you shouldn’t be able to see them at the same time on Earth. The LMC is ~ 14,000 ly across, so even if we were viewing it along its longest dimension ( which I don't think is the case), 14,000 years is the most time separation we would see. Planetary Nebula last for 10's of thousands of years. That being said, I don't think those rings are planetary nebula. Link to comment Share on other sites More sharing options...
Eise Posted April 23, 2019 Author Share Posted April 23, 2019 10 hours ago, Janus said: The LMC is ~ 14,000 ly across, so even if we were viewing it along its longest dimension ( which I don't think is the case), 14,000 years is the most time separation we would see. Planetary Nebula last for 10's of thousands of years. That being said, I don't think those rings are planetary nebula. My thought too. But if they are not planetary nebulae, what are they? Link to comment Share on other sites More sharing options...
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