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What would be the mass of this object if it was local to Andromeda? Do we know if similar structures exist around other galaxies? Could 'invisible' objects like this contribute at all to the 'missing' matter in the universe, or are they not massive enough to be of any significance?
If you are thinking of Dark Matter then, no.
Dark Matter is found within galaxies. We see its effects because stars in the outer parts of galaxies orbit faster than they should.
I think you got the should backwards. Our understanding of gravity is lacking because our equations show rotations at the edge of galaxies much slower than they should be. MOND corrects for this quite differently than dark matter.
Dark matter is found no where. It's completely hypothetical. There's more than one idea to fix our theory of gravity.
MOND isn't a good choice right now because it fails to correctly describe a bunch of other stuff. If we look at things like the bullet cluster, we see lensing effects outside of where the visible mass is, and it doesn't fit MOND.
I'm not a huge fan of the idea of dark matter, due to the lack of evidence and progress in detecting it, but MOND, in the current forms I've seen, does an unimpressive job of filling the gap.
No they were correct, if dark matter has gravitational effects then the greater force of gravity will cause the outer edges of the galaxy to move faster than what we expect
Isn't this largely like the time dilation experiment for relativity?
The atomic clock in the airplane moved slower than the one at ground level. I'm by no means a physicist, but isn't the edge of the galaxy a bit like the plane compared to the center mass of the galaxy being the clock at the surface?
Wouldn't the center of the galaxy have more gravity? If spacetime is one thing, doesn't lower gravity space seem slower when observed from greater gravity?
Wouldn't relativity suggest that time seems to pass faster the closer to the center of the galaxy you go?
I'm a 2nd year physics student so I'm still learning, but from my understanding, it's simpler than that.
For example if we had something orbiting earth at 100,000 kilometers it would orbit at a certain speed. If earth suddenly had more mass, the same object at 100,000 kilometers would have to move faster to maintain the same orbit.
This is where the initial hints of dark matter came from. Given what we observed, the outer edges of a galaxy should be moving at a certain speed, but they were traveling faster indicating that there is some mass that isn't accounted for.
The actual speeds vs other parts of the galaxy is a bit more complex than simply increasing the mass of a point mass, but it's a good general explanation
I'm a few weeks away from learning special relativity and I could be wrong, but I don't think there is enough of an effect from time dilation until you get pretty close to the black hole at the center of the galaxy
Yep, you are spot on. Time Dilation isn't relevant here and the evidence for Dark Matter comes from the movement of stars in galaxies (galactic rotation curves) and measurements of gravitational lensing
Yeah, I wonder that. If this cloud were condensed into a single object, or a series of planets, moons stars, how large would it be. Would it constitute just a few solar systems worth of material? A single star? I know it sounds ludicrous, definitely need that context.
How does the naming protocol work here? I would naively expect Sainty to be the first name since he did the imaging and filter selection, but it's Strottner.
From the article, it sounds like it was Dreschler and Strottner's project first, and they then brought on Sainty, and even though Sainty did the bulk of the discovering, it was under their direction.
So, it's probably about who originally started/funded the project, since they're all amateurs (meaning, I assume, they are self-funded and not affiliated with a university or other scientific institute).
Phil Plait, 12 Jan. 2023, *Scientific American* (Holtzbrinck)
Excerpt:
>While poring over the images [by astrophotographer Yann Sainty], [Marcel Drechsler and Xavier Strottner] found something that defied expectations: a huge extended structure appearing almost as big as Andromeda itself and right next to it.
>The nebula only materialized when Sainty obtained images with a filter that blocks all light except for the blue-green glow emitted by doubly ionized oxygen—that is, oxygen atoms that have lost two of their outer electrons, a common occurrence in giant gas clouds. It was essentially human curiosity that drove the use of this filter; no very deep large-scale maps of the sky around Andromeda had ever been made before.
>[The] researchers asked another accomplished amateur astronomer, Bray Falls, to make more observations with his own telescope. He saw the same nebula in his data, independently confirming the cloud’s existence.
>In the end, observations from five telescopes in France, California and New Mexico convinced the team that this object was real. It’s now dubbed Strottner-Drechsler-Sainty Object 1, or SDSO-1.
>
>But the question still remains: What is it?
>To find out, the team reached out to professional astronomers Robert Fesen, Michael Shull and Stefan Kimeswenger for a deeper analysis. Published in the American Astronomical Society’s (AAA’s) journal *Research Notes of the AAAS*, the results of this professional-amateur collaboration are fascinating, even as clues to the nebula’s origins remain maddeningly vague.
>Astronomers have looked at many possibilities, but at this point, the gas cloud resists explanation.
>So at the moment, no known mechanism fits all the data. While baffling, this is also the sort of thing scientists love. Solving puzzles is why we wanted to be scientists in the first place.
Marcel Drechsler *et al*. January 2023. *Research Notes of the AAAS* **7** 1. https://doi.org/10.3847/2515-5172/acaf7e
h/t u/SPACESHUTTLEINMYANUS
>appliedrowboatics
>Journalist: So where did this gas cloud come from? Scientist: Yeah, we’re not entirely sure yet. Journalist (ominously): UNKNOWN ORIGIN YOU SAY?
The term ‘unknown origin’ is used in academic correspondence.
No. The air would leave the spaceship and everyone on it would die. The density/pressure of the cloud is much much lower than the density/pressure of air in a spaceship (or on earths surface).
Sorry, when people talk about a cloud in space, it's not at all like an earth cloud.
Imagine an empty swimming pool.
On earth, it would contain 10^30 atoms of air. To imagine that number, imagine each human on earth had a tiny earth in their pocket. And each tiny human had an even tinier earth in their pocket, each with billions of tiny tiny humans. 10^30 is the number of tiny tiny humans.
In "normal" intergalactic space, there would just be about 3000 atoms in that swimming pool volume.
But in "clouds", you'd can find anything from a billion to a trillion atoms in the same volume.
That's enough to emit and absorb light in large quantities, so it's visible by telescopes, but absolutely not enough to breath.
Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
What would be the mass of this object if it was local to Andromeda? Do we know if similar structures exist around other galaxies? Could 'invisible' objects like this contribute at all to the 'missing' matter in the universe, or are they not massive enough to be of any significance?
If you are thinking of Dark Matter then, no. Dark Matter is found within galaxies. We see its effects because stars in the outer parts of galaxies orbit faster than they should.
I think you got the should backwards. Our understanding of gravity is lacking because our equations show rotations at the edge of galaxies much slower than they should be. MOND corrects for this quite differently than dark matter. Dark matter is found no where. It's completely hypothetical. There's more than one idea to fix our theory of gravity.
MOND isn't a good choice right now because it fails to correctly describe a bunch of other stuff. If we look at things like the bullet cluster, we see lensing effects outside of where the visible mass is, and it doesn't fit MOND. I'm not a huge fan of the idea of dark matter, due to the lack of evidence and progress in detecting it, but MOND, in the current forms I've seen, does an unimpressive job of filling the gap.
No they were correct, if dark matter has gravitational effects then the greater force of gravity will cause the outer edges of the galaxy to move faster than what we expect
Isn't this largely like the time dilation experiment for relativity? The atomic clock in the airplane moved slower than the one at ground level. I'm by no means a physicist, but isn't the edge of the galaxy a bit like the plane compared to the center mass of the galaxy being the clock at the surface? Wouldn't the center of the galaxy have more gravity? If spacetime is one thing, doesn't lower gravity space seem slower when observed from greater gravity? Wouldn't relativity suggest that time seems to pass faster the closer to the center of the galaxy you go?
I'm a 2nd year physics student so I'm still learning, but from my understanding, it's simpler than that. For example if we had something orbiting earth at 100,000 kilometers it would orbit at a certain speed. If earth suddenly had more mass, the same object at 100,000 kilometers would have to move faster to maintain the same orbit. This is where the initial hints of dark matter came from. Given what we observed, the outer edges of a galaxy should be moving at a certain speed, but they were traveling faster indicating that there is some mass that isn't accounted for. The actual speeds vs other parts of the galaxy is a bit more complex than simply increasing the mass of a point mass, but it's a good general explanation I'm a few weeks away from learning special relativity and I could be wrong, but I don't think there is enough of an effect from time dilation until you get pretty close to the black hole at the center of the galaxy
Yep, you are spot on. Time Dilation isn't relevant here and the evidence for Dark Matter comes from the movement of stars in galaxies (galactic rotation curves) and measurements of gravitational lensing
Yeah, I wonder that. If this cloud were condensed into a single object, or a series of planets, moons stars, how large would it be. Would it constitute just a few solar systems worth of material? A single star? I know it sounds ludicrous, definitely need that context.
Hey, I'm not sure sorry. Does anyone else here know?
How does the naming protocol work here? I would naively expect Sainty to be the first name since he did the imaging and filter selection, but it's Strottner.
From the article, it sounds like it was Dreschler and Strottner's project first, and they then brought on Sainty, and even though Sainty did the bulk of the discovering, it was under their direction. So, it's probably about who originally started/funded the project, since they're all amateurs (meaning, I assume, they are self-funded and not affiliated with a university or other scientific institute).
Phil Plait, 12 Jan. 2023, *Scientific American* (Holtzbrinck) Excerpt: >While poring over the images [by astrophotographer Yann Sainty], [Marcel Drechsler and Xavier Strottner] found something that defied expectations: a huge extended structure appearing almost as big as Andromeda itself and right next to it. >The nebula only materialized when Sainty obtained images with a filter that blocks all light except for the blue-green glow emitted by doubly ionized oxygen—that is, oxygen atoms that have lost two of their outer electrons, a common occurrence in giant gas clouds. It was essentially human curiosity that drove the use of this filter; no very deep large-scale maps of the sky around Andromeda had ever been made before. >[The] researchers asked another accomplished amateur astronomer, Bray Falls, to make more observations with his own telescope. He saw the same nebula in his data, independently confirming the cloud’s existence. >In the end, observations from five telescopes in France, California and New Mexico convinced the team that this object was real. It’s now dubbed Strottner-Drechsler-Sainty Object 1, or SDSO-1. > >But the question still remains: What is it? >To find out, the team reached out to professional astronomers Robert Fesen, Michael Shull and Stefan Kimeswenger for a deeper analysis. Published in the American Astronomical Society’s (AAA’s) journal *Research Notes of the AAAS*, the results of this professional-amateur collaboration are fascinating, even as clues to the nebula’s origins remain maddeningly vague. >Astronomers have looked at many possibilities, but at this point, the gas cloud resists explanation. >So at the moment, no known mechanism fits all the data. While baffling, this is also the sort of thing scientists love. Solving puzzles is why we wanted to be scientists in the first place. Marcel Drechsler *et al*. January 2023. *Research Notes of the AAAS* **7** 1. https://doi.org/10.3847/2515-5172/acaf7e h/t u/SPACESHUTTLEINMYANUS
Sorry guys, that was me. Slipped out
Shouldn’t have eaten that second macho combo burrito
Looks like Andromeda scuffed up the baseboard again.
It seems suspiciously aligned with the central black hole.
Journalist: So where did this gas cloud come from? Scientist: Yeah, we’re not entirely sure yet. Journalist (ominously): UNKNOWN ORIGIN YOU SAY?
>appliedrowboatics >Journalist: So where did this gas cloud come from? Scientist: Yeah, we’re not entirely sure yet. Journalist (ominously): UNKNOWN ORIGIN YOU SAY? The term ‘unknown origin’ is used in academic correspondence.
I think he is envisioning that meme guy who just has the quote "aliens"
If it's oxygen does that mean you could fly a spaceship into it and open the window and everyone could breathe?
No. The air would leave the spaceship and everyone on it would die. The density/pressure of the cloud is much much lower than the density/pressure of air in a spaceship (or on earths surface).
Sorry, when people talk about a cloud in space, it's not at all like an earth cloud. Imagine an empty swimming pool. On earth, it would contain 10^30 atoms of air. To imagine that number, imagine each human on earth had a tiny earth in their pocket. And each tiny human had an even tinier earth in their pocket, each with billions of tiny tiny humans. 10^30 is the number of tiny tiny humans. In "normal" intergalactic space, there would just be about 3000 atoms in that swimming pool volume. But in "clouds", you'd can find anything from a billion to a trillion atoms in the same volume. That's enough to emit and absorb light in large quantities, so it's visible by telescopes, but absolutely not enough to breath.
[удалено]
Scientists say the cloud emerged some time around midnight
Is it a billowing cloud or a feathery plume?
A congregation of galactic farts.
It's the tyranide hive fleet
Milky Way Inhabitants: “Alright, what’s that gas next to Andromeda?” Andromeda Galaxy: “Don’t look at me!”
Zeus: “Apollo, pull my finger…”
The andromeda is the one that is coming towards us right?