> and its mass is estimated to be 650 billion solar masses
One could also say this new galaxy's mass is estimated to be 0.565 Milky Way masses, but for some reason that unit of mass seems not to have caught on...
Isn't there a lot of uncertainty about the mass of the milky way? I think if you are going to use something as a unit you really need an accurate figure.
There is indeed lots of uncertainty, and all Milky Way mass estimates are model dependent. Also, the ~10^12 solar mass figure referred to above is an estimate of the total galaxy + dark matter halo mass. Stellar or baryonic mass estimates are closer to ~6 x 10^10 solar masses. I'm using "~" to mean uncertainty to within a factor of 2 or so.
"massive and compact" sounds like an oxymoron until you consider that "massive" is being used in its more techically correct meaning of "a lot of mass" rather than its more common/popular usage to mean "large" or "imposing".
The idea of light bending around gravitational fields is so fascinating. I wonder if there's a part of the night sky where some photons that bounced off the earth billions of years ago are being directed back at earth.
In my fever dreams these galaxies and their theoretical descendants the elliptical galaxies are the result of intelligent life engineering them in a way that is practically required by physics. A sort of natural outcome produced by the inevitable evolution of intelligent life in a galaxy of a certain size. (The evidence for this is essentially negative, fwiw. It’s just a day dream.)
You might like Count to the Eschaton (starting with Count to a Trillion) by John C. Wright. IFF I'm understanding you correctly, there's a great moment in it that is very much like this fancy.
Reality may be "boring" in that earth just may be super dooper lucky to have an accidental massive moon, a liquid iron core and a seasonal tilt to have made life. We also may be one of the first early conscious life in the universe (which would suck).
The really sad part is due to the laws of physics there is only a very limited bubble of time that we can ever see into the universe even if humans survive millions of years (unlikely).
I tend to think that one of the better results it that we are early. I think, given the evidence, the only other good scenario is that we just don't know what we're seeing.
My guesses are that either new physics makes civilizations invisible to us once discovered or the much more mundane intelligent life develops along a path as to not care to be visible or do the kinds of things we could see.
If individuals had billion year long lifespans, sightings might just be staggeringly rare.
Within the framework of falsifiable natural science, of the following three viewpoints two are hopelessly incoherent and one makes rational sense; can you spot which one that is?
A. “Per our understanding of the universe, which is now finally provably correct and complete, no intelligent life whatsoever could have been causally involved in the emergence of various stellar objects or humanity itself.”
B. “Since our understanding of the universe is most likely incorrect and/or incomplete, some kind of intelligent life we are not yet aware of may or may not have been causally involved in the emergence of various stellar objects or even humanity itself.”
C. “We were made by fantasy abstract creature(s) not subject to any physical laws of this universe. We should probably worship them.”
Well, sure, if you throw in something like "which is now finally provably correct and complete", you get to be right. Of course, that's not how science works, but I guess you have some audience you need to polish your anti-science creds to.
I merely defend the comment that claimed a perfectly scientifically valid (if far-fetched) possibility. With a sarcastic comment likening that idea (B) to creationism, you implicitly adopt A, and let me tell you—it is closer to actual creationism (C) than you might like.
Creationism is about creation. I’m talking about intelligent life spreading through a galaxy and manipulating it over the course of billions of years. Is an iphone creationism?
Creationism is LITERALLY the belief that the universe and was created by a supernatural and divine being(s). Supposition that intelligent life may have developed the technology to modify things at a galaxy scale in no way implies a divine being.
Well, we were keeping to science and physics mostly until now, and I don't see why it needs justification that hinduism is esoteric in that context. As in, too "magical". Not many [astro]physicists would apply hinduism in their work I imagine. Same for any religion I guess
Ah, I found it intellectually stimulating to draw the comparison to such an ancient and commonly followed school of philosophical thought so it felt worth sharing.
I'm not sure there's anything less "mystical" about Wolfram's postulations though. Is there a new scientific basis for these beliefs?
Interesting. To me Wolfram's writing seems following logic/reason from first principles more so than what I know about Hinduism, but I guess I don't know that much about it...
"More massive galaxies tend to form in more massive dark matter halos according to our best current theories." Many believe that MOND may better explain observations, and JWST continues to be a great source of data that may help us update our best models. I believe this commenter was indicating with their prediction that our current theories of dark matter are wrong.
Last time i looked into MOND it remains relatively unconvincing. The primary reason for this being that it is hard to make the universe look like it should with simulations. We are doing better so far with the lambda-CDM model so far.
If someone comes up with a MOND simulation that is better than our current ones it may gain more traction.
“Dark matter” is a number of observed phenomena that independently hint at presence of matter not visible by other means, and when estimate can be inferred from observations give roughly the same estimate for the mass of that matter. There is no conventionally accepted explanation of dark matter, but great thing about scientific method is that it aims to capture facts and observations without interpretation.
So I stand behind “dark matter is obviously correct”. Although I’m pretty sure that WIMPs are BS.
"Phlogiston"/"ether"/take-your-pick-of-fictitious-forces was a number of observed phenomena that independently hint at presence of an active force not visible by other means, and when estimates can be inferred from observations give roughly the same estimate for the existence of that force.
Except none of these things are properly said to exist.
Dark matter is and always has been "fitting gaps in our current model to observed data". It's retroactive by construction and almost the definition of begging the question. Explanations for material origins as "dark matter" have nothing to do with reality and everything to do with a lack of imagination and humility.
I could explain fire by positing and observing phlogiston by fitting the residuals of incomplete models to data and I would have just as much "evidence" to stand on as dark matter zealots.
It is extremely anti-scientific, indeed an offense to the process of science itself, to 1) ignore the basic facts above to inform the assertion of such baseless claims and 2) to assert those claims so strongly.
If several independent observation gave a similar estimation for the mass of “phlogiston” or density of “ether” that would be a very significant phenomena worth studying.
Phlogiston was a result of multiple independent observations: combustion, rusting, any number of exothermic reactions... it was still wrong.
As a bit of an aside, I've noticed a strong correlation with misuse of the singular and plural forms of the word "phenomenon" with non-physicists who want to sound like they know what they're talking about. By your standards, I have a pretty good theory that you're not a physicist. Are you comfortable applying your flavor of analysis and rigor to this observation, too...?
I have MS in Physics but didn’t pursue a PhD and went for job in programming for money. Not sure if it counts or not. English is not my native language and most of my papers were in my native language (except one in Physical Review Letters), so my ‘physics English’ is pretty bad.
I find this attitude against dark matter frankly baffling...without positing what it is your argument reads somewhat like "well night technically has all these things in it so dark nights don't exist".
Screams of tortured tautology, sure there are some "residuals", but unless you are shooting down a particular incorrect assertion there's nothing wrong with lumping a set of observations under some banner. I'm sure we won't call it dark matter at some point, just as we no longer think of atoms as being atomic...nevertheless dark matter serves a purpose in our current state of ignorance, being mad or upset at that to me makes no sense.
You know that meme about deep learning engineers saying "JuSt AdD lAyErS"? This feels like the "matter" version of that.
We don't call "ether" a precursor to modern theories, we call it a wrong theory, because there is no substance "ether" which exists. We don't say try to justify their use of the word "ether" because of some tenuous you-know-what-they-meant wink-and-nod, it was just wrong. Newtonian mechanics was at least right in the limit.
At least with the atoms example it's a useful abstraction (see: atomic physics, chemistry) but there's no use to positing matter exists if the mechanism is really completely different from invisible matter. We could just as easily call it "the galactic explanatory gap" and maybe name it after someone who did a lot of work on it, maybe "the Zwicky tension" or something, without asserting the nature of the issue so strongly.
Ok, I sort of get your objection, but "if the mechanism is really completely different from invisible matter", that doesn't seem to be true?
I'm not a physicist, but the explanation I'd heard was that something appears to have mass (due to patterns of gravitational objects seen through telescopes), but we can't see it.
So to be completely fair, we don't see any matter, we do see unexplained gravitational phenomena, which is optically invisible, but we do see something. Possibly, our model of gravitation is just completely wrong, and actually there are different forces which modulate the force of gravity.
Of the two, it seems dark matter is less controversial (matter that doesn't seem to reflect light) than positing new fundamental forces, as one involves a known set of theories (maybe its something like antimatter, or an alternative configuration of particles to the standard atomic ones at a quantum or particle physics level). I don't think ignoring it as a rounding error is a reasonable approach, unless you have some strong sources arguing that the physicists equipment is just bad (source, please), at least that's my impression.
Again, I can make anything "appear" to have invisible mass if I ignore the appropriate theories and fit mass in where it "ought to be" to recover the observed dynamics.
Theories besides dark matter don't posit new fundamental forces, they posit that our understanding of gravity is incomplete and only applies in the limit of high-mass-density spacetime regions. This kind of elaboration of our physical theories has significant precedent: Newtonian mechanics is recovered when considering general relativity in the limit of distance scales much smaller than light-seconds and time scales much longer than infinitesimal time. It could be as well that our current models are only applicable in the limit of regions of dense mass. When things thin out (say, near the edges of galaxies) the transition to a modified dynamics appears to have significant explanatory power (since the limit no longer applies) with the added benefit that there's actually a model that can be validated or falsified.
I'm not an armchair physicist, I'm actively working on my PhD in Physics.
Dark matter is the prevailing theory because it best explains our current observations. I'm aware that doesn't mean its right, and we don't have conclusive proof that it is.
There's definitely a problem with our current model looking at the Hubble tension, but the reason for that is still unknown.
So I love when armchair physicists come in and say dark matter is obviously wrong.
"Best explains our current observations" is tautological because you can imagine invisible mass for any system to explain arbitrary observations provided you are only modeling the system instantaneously (note galactic vs human timescales). Dark matter fanatics want to assert the supremacy of a system that is literally derived by fitting residuals using computational models, but anything can be explained that way using results of a simulation if you wanted.
I could elaborate a complicated system of invisible mass to explain geocentrism if I wanted. Doesn't make it a good model.
You will note I didn't actually say "dark matter is wrong" but rather "there is nothing to the very foundations of the model itself". I'm not arguing against dark matter so much as for a theory of substance.
Not paid enough to afford an armchair, you mean? :)
> it best explains our current observations
I always figured dark matter to be nonsense because nobody ever listed any said observations, but only ever parroted that line. Even xkcd is guilty of it https://xkcd.com/1758
So better start giving out examples or you won't ever convince anyone. I'll start. The one that convinced me is the Bullet Cluster collision where it seems that regular matter collided and slowed down but something else which contributes most to the overall mass passed right through without interacting at all: https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to...
So the galaxy itself is the orange ball in the middle, right? The ring around it is light from another galaxy way further behind being warped by the orange ball?
One could also say this new galaxy's mass is estimated to be 0.565 Milky Way masses, but for some reason that unit of mass seems not to have caught on...