- the quotes around image in the title
- the commenter believes image is the correct word in a more literal sense
the lowest mass dark object currently measured
one million times the mass of the Sun
Sometimes you read things that remind you how vast and untamable our universe really is.There's no reason to think that our senses encompass the vast majority of understanding everything in reality and current evidence that they, in fact, do not, via dark matter as a primary source.
I suspect our senses encompass a meaningless fraction of the noumenon.
To elaborate, the noumenon can have properties that are unknown to us and outside the purview of certain senses (if not all) but still have partial phenomenal effects such as gravitational effects.
Given partial overlap, we could, and likely should, surmise that overlap, if partial, can also be zero. In fact, partial overlap with certain things (such as the gravitational field) but no sensory experience is exactly what we'd predict if this were true.
The mistake is thinking I'm asserting that things are phenomenon or noumenon when that's not quite right. Mostly, the supposition is that things can exist and have either 'full' (unlikely I think), partial, or zero overlap with our sensory experience. Things that demonstrably have partial overlap suggest a wider world of things. I simply find the idea that our evolved sensory experience encompass even a sizable fraction of reality to lack epistemic humility.
This is obviously speculative.
This is at the heart of the Allegory of The Cave: https://en.wikipedia.org/wiki/Allegory_of_the_cave. What we're discussing is a kind of "Natural Philosophy" or Physics, the study of that which is.
We are surrounded by dark objects, a rock is a dark object, exoplanets are dark objects, and so are black holes. Pretty much everything but stars are dark objects. They are all dark because they don't emit light.
Here, I think they mean stuff (whatever it is) that can only be detected by gravitational lensing, and it makes sense that it has to be extremely heavy, because gravity is so weak.
Actually, dark matter does interact with electromagnetic radiation -- it can deflect it, as in the case of gravitational lensing. But dark matter doesn't either emit nor absorb electromagnetic radiation directly.
We only know about dark matter because of its gravitational effects.
They are much lighter than 1 million solar masses and we know a few of them, with a variety of ways to detect them, including companion stars orbiting around them and gravitational waves during mergers.
Black holes fit the definition of dark matter, as they neither emit nor absorb electromagnetic radiation, not in a way that could be detected anyways. This is the "MACHO" theory of dark matter, which is not the favorite, but it is still taken seriously. Stellar mass black holes have been ruled out, I think, but it doesn't mean dark matter can't be made of black holes. In fact, primordial black holes are a rather hot theory.
Dark matter seems more ghostly , like gravitational shadow of matter
They're explicitly looking for "Dark Matter", which doesn't "interact" with normal ("baryonic") matter or electromagnetic radiation (e.g. light). So it's not a black hole for sure, as those are composed of regular ol' matter.
RE:"dark star", that's really up in the air, I'd say! AFAICT the only academic reference to that term is for normal stars influenced by dark matter[1], but kinda the whole problem here is that we don't know much about what dark matter is composed of or into. Certainly it's not going to be a star in the traditional sense as it can't emit light, but I'm not aware of any reason this object can't end up being a giant sphere.
FWIW, Wikipedia says "One of the most massive stars known is Eta Carinae, with 100–200 [solar masses]", whereas this object "has a mass that is a million times greater than that of our Sun". If we're going to use metaphors, I think "dark dwarf galaxy" might be more appropriate?
https://en.wikipedia.org/wiki/List_of_most_massive_stars#Lis...
Dust clouds have those mass ranges. It’s not a galaxy-scale mass by any measure.
This thread has a lot of CS people being confident about physics.
But it's really so---according to GR, black holes don't have global charges. So even if you see a star made out of baryons collapse into a black hole, once the BH settles down into a steady state you can't say it's "really" got baryons inside: the baryon number gets destroyed.
(Of course, a different model of gravity that preserves unitarity might upset this understanding.)
I think you mean it doesn't interact electromagnetically with either matter or radiation. It does interact with normal matter via gravity -- that's pretty much the strongest (only?) argument for its existence.
I'm not aware of any reason this object can't end up being a giant sphere
AIUI, most theories posit that solid spheres of dark matter are very unlikely because matter accretion is governed by electromagnetism in addition to gravity, and dark matter is not supposed to obey the former. Most models assume that dark matter is organized in gaseous clouds (halos); strictly speaking that's still a giant sphere, just not in the same way that Jupiter or the Sun or even the Oort Cloud is.
The paper is more about the technical achievement of detecting it, IIUC. It’s not the first dark matter inference we’ve had, and doesn’t really tell us anything new about the stuff.
The research team detected it only through its gravitational lensing effect — the way it slightly distorted the light from a more distant galaxy. There’s no emission at any wavelength (optical, infrared, or radio), and its gravitational signature matches a million-solar-mass clump of invisible mass rather than a compact point source like a black hole.
They specifically interpret it as a dark matter subhalo — one of the small, dense lumps that simulations of “cold dark matter” predict should pepper the universe’s larger halos. It’s too massive to be a single star, far too diffuse to be a stellar remnant, and not luminous enough to be a faint galaxy.
So “dark” here isn’t just shorthand for “too dim to see at this distance” — it’s used in the literal physical sense: matter that doesn’t emit or absorb light at all, detectable only via gravity.
Eventually, all the dark matter clumps into rings around galaxies, but since this one is so distant, ~10B light years, so we are seeing that clump as it was that long ago before it difused into it's ring shape we can see in the galaxies around us.
From the abstract: “This is the lowest-mass object known to us, by two orders of magnitude, to be detected at a cosmological distance by its gravitational effect. This work demonstrates the observational feasibility of using gravitational imaging to probe the million-solar-mass regime far beyond our local Universe.”
Assuming this is repeatable, it will take a while to contextualize.
This is cool as heck, and now I’m going to go back to my computer job and try not to think about how ridiculously tiny and fragile my little life is.
> This is cool as heck, and now I’m going to go back to my computer job and try not to think about how ridiculously tiny and fragile my little life is.
There could be an alternative take here: we really lucked out that life as we know it exists at all. So we kinda won the lottery already.
That being said... I'd love to if I were terminally ill yet capable enough to understand what was happening -- to be yeeted into a super super massive blackhole that was not feeding such that I would not be torn to shreds or vaporized by the accretion disk and ultimately understand what lies at the center of my now time horizon...
The title reads like astronomers found a mysterious dark object in another universe. Like a distant solar system or a distant galaxy.
Or am I misunderstanding the findings here?
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https://www.youtube.com/watch?v=t_XqHWx-v_Y