Dark matter Definition and 935 Threads

"What the theory of dark matter predicted is not what we see," said Case Western Reserve astrophysicist Stacy McGaugh, whose paper (12.11.24) describes structure formation in the early universe. McGaugh, professor and director of astronomy at Case Western Reserve, said instead of dark matter...

The second half of 2024 has seen the results from 3 years of data from the Lux Zeplin experiment in South Dakota, USA. Despite their attempts to put a positive spin on this, the bottom line is - no dark matter. Just three months before that the ATLAS experiment from CERN in Geneva, Switzerland...

Hello, I'm Sofia and new here! I'm working on a project in which I'm trying to show that dark matter exists. It's about an elliptical galaxy with a rotating gas disk. What I'm doing is comparing the theoretical calculation of the rotation curve with the actual measured rotation curve. It...

"... the gas between the galaxies collided, becoming turbulent and superheated. While both dark and normal matter are influenced by gravity, the normal matter also interacts via electromagnetism, which slowed it down during the collision. Consequently, the dark matter moved ahead, decoupling...

Hey guys! I'm excited to be a part of this community and can't wait to answer some questions and of course , ask some as well. I'm in the final year of my master's degree and currently working on primordial black holes and their candidacy for dark matter. Ad Astra per Aspera!

Is it correct to say that the reason why stars at the periphery of galaxies are observed to orbit faster than can be accounted for by Newtonian physics is because they are gravitationally bound to relatively high density distributed matter also present at the periphery that must be attributed to...

If this post should be in another forum, please advise so I can post there instead. I hope I got the right prefix. Thank you. 1) Is it possible for Hawking Radiation to be dark matter, at least in part? Do the equations rule out this possibility? 2) Are Black Holes actually spinning or is our...

hobbyist, passionate studing of issues such as the nature of gravity, the LamdaCDM model, the dark matter, the dark energy, and the prevalence of ordinary matter over antimatter (baryogenesis)

The existence of dark matter was initially proposed to address discrepancies between observed galaxy rotation curves and the expected behavior dictated by our current understanding of gravity. Typically, it's argued that stars at the edges of galaxies rotate faster than expected, leading to...

Here is the article titled "In a ‘Dark Dimension,’ Physicists Search for the Universe’s Missing Matter" by Quanta Magazine https://www.quantamagazine.org/in-a-dark-dimension-physicists-search-for-missing-matter-20240201/

If dark matter really lives up to it's name and truly is some form of matter, then wouldn't it feed black holes given extreme gravitational regime in a black hole?

Does the astrophysics community really think dark energy/matter is real, or that we just haven't figured out the actual physics of what is happening and this just makes it work out (to our current understanding).

i am working on an alternate explanation of dark matter i am looking for data sets of rotational and the apperant mass for the same galaxy multiple data sets would be helpfull.

Regarding the following statement: "It would appear Dark matter and dark energy are what existed BEFORE the visible universe as we know it came into being. When you look at galaxies what you're seeing could be described as "displacements" in dark matter where ordinary matter formed and took...

Hello, I have asked a similar question before, but this time I want to ask it a bit differently to be understood better. I am a physics student at a university and this semester I am going to make a term project about Dark Matter Density Distribution by using rotation curves. However, I am a...

This problem builds on my previous post, where we calculated that core's mass is ##M_1=\frac{{v_0}^2r_1}{G}##. So if we consider mass of dark matter dependent on distance ##r## to be ##M_2(r)##, we can calculated it from ##G\frac{(M_2(r)+M_1)m}{r^2}=m\frac{{v_0}^2}{r}.## So...

It is clear that the speed is constant because dark matter hasa gravitational effect on stars, so when a star is further from the core, gravitational force of it is smaller, but the net gravitational force of dark matter is bigger. So the net force acting on each star has to be the same. So...

Is the basic idea behind the CDM theory regarding the production of the Universe's large scale structure simply that dark matter, being dark, doesn't interact with photons, and thus was able to coalesce gravitationally soon after the Big Bang, forming the scaffolding toward which regular matter...

Hello! I am a highschooler looking to learn more about physics and looking to hear a lot of feedback on my thoughts about physics.

How do we distinguish between the effect of dark matter and MOND with respect to flat rotation curves in galaxies? How would the shape of the rotation curve differ between the two?

I am looking for examples of Modified Gravity theories that have been developed with the aim of dispensing dark matter, besides Milgrom's [MOND][1], Bekenstein's [TeVeS][2], and the recent relativistic version of MOND ([RMOND][3]) by Skordis and Zlosnik. Are there any other examples of similar...

A collaborative effort is yielding a Dark Matter picture of the universe from microwave (CMB) data collected by the Atacama Cosmology Telescope. Major sections of the sky have already been imaged. Those are shown in the image below as the red/blue speckled regions (from a University of Toronto...

"Superfluid dark matter in tension with weak gravitational lensing data" (Mistele, McGaugh, Hossenfelder) Regarding this paper, Sabine Hossenfelder tweets One comment summarizes this as

I am by no means an expert in physics, but I have a question. We have recently found the particle that cause attraction (Bos-Higgs) would it not be reasonable to think the there is a particle that cause repulsion? That would lead to cluster of attraction surrounded by fields of expansion. Would...

I'm after some raw data for testing theories of dark matter in galaxies. Basically what I want is table showing visible mass vs total mass within different radii (or, observed rotational velocity vs expected rotational velocity without dark matter). Plus error percentages. And ideally, for...

I was thinking about how the dark matter theory was proposed due to inconsistencies with observed mass vs the calculated required mass for a galaxy to exist. Just wondering how we know its not just stray exoplanets or possibly even smaller collapsed stars, really any kind of mass that wouldn't...

When dark matter is called collisionless, does it only mean that they do not collide and scatter, or does it also mean that there is no other significant non-contact interaction?

We do not seem to have any unexplained orbital/gravitational anomalies within the solar system. What does that imply for the local dark matter distribution?

It is said that CMBR indicates that dark matter is non-baryonic. How so?

Direct Observation of Whim (The warm–hot intergalactic medium) has known a lot progress recently. Does whim could be enough to amount to the quantity of dark matters in the universe, therefore solving the dark matter problem? If not, why?

Quote from NASA: My understanding of dark energy is based on NASA's report: https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy; were NASA state as follows: "It turns out that roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest - everything on...

could this explains the 3rd peak of the CMB and dark matter cold Primordial neutron star High Energy Physics - Phenomenology [Submitted on 7 Sep 2022 (v1), last revised 12 Sep 2022 (this version, v2)] Primordial neutron star; a new candidate of dark matter M. Yoshimura Z-boson exchange...

I was reading a thread on my phone that was reviewing a paper about DM being explainable by gravitomagnetic effects. Now I can't find it in any search. It was on its fourth page - so at least 80 posts over at least two years. Anyway, what I wanted to ask was for a description that a layperson...

How do we know that cold neutrinos do not make up 100% or a large percentage of the dark matter content in the universe? In my mind, the only way to prove that dark matter is not simply cold neutrinos would be to measure the density of cold neutrinos in the universe and then calculate the...

Is it possible to identify a volume of space, observationally/statistically, that represents the 85:15 % ratio of dark matter and matter?

Do all galaxies with dark matter halo have flat rotation curve?

The article is pop but there is a paper Pop article https://www.vice.com/en/article/g5vvjw/the-universes-oldest-light-reveals-unprecedented-dark-matter-patterns Paper. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.061301 The language is a little bit click bate, I just wanted...

How are related these 3 concepts?

Is the bullet cluster evidence for or against dark matter? I understand the explanation that it is evidence in favor of the existence of dark matter, and it convinces me. However, some argue that it is evidence against its existence? Why?

A new group of investigators are attempting something similar to Deur's work, which seeks to explain dark matter phenomena with general relativity corrections to Newtonian gravity is systems like galaxies. Deur's most similar publication to this one along these lines was: One thing that makes...

Today 16:00 UTC, in ~7.5 hours. Announcement, Link to Zoom meeting (why is this just an image on the website, not a link?) LUX-ZEPLIN (LZ) uses several tonnes of xenon to search for signals of dark matter interacting with it. It started taking data last year and it should easily set better...

Is it possible that galaxies are spinning faster than expected due to a particular configuration of the moving mass and not due to dark matter?

what about Modified Newtonian Dynamics + dark matter both right and both correct Are sterile neutrinos consistent with clusters, the CMB and MOND? Garry W. Angus arXiv:0805.4014 [ If no sterile neutrinos then Modified Newtonian Dynamics + primordial black holes Primordial Black Holes...

Summary:We propose a search for low mass dark matter particles through momentum recoils caused by their scattering from trapped, nanometer-scale objects. The Paper linked details a novel concept for detecting WIMPs. I hope to see more work performed on the idea in the future...

Does dark matter(DM) fall into black holes(BHs)? IMHO it should... ...as it does interact with normal matter gravitationally. Once it's done so, does it add to the BH's mass? Again, IMHO it should. AFAIK it does have mass... Would that "quasi-convert" it to normal matter? ...after all, this...

Unsurprisingly the Milky Way seems to have been studied a lot. We have really good luminous mass profiles (e.g. McMillan 2011) and increasingly accurate circular velocity observations for stars at various radiuses (e.g. Eilers 2019) meaning we can confidently infer dark matter models. So the...

This thought surprisingly came from thinking about the definition of temperature and the symmetry breaking that separated time from temperature. Which led to thoughts about symmetry breaking that separated QM from GR. Which led to to the symmetry breaking that separated dark energy from baryonic...

Originally Answered: If light reaches the Earth from the sun, why is the space between the sun and the Earth dark? Because light illuminates surfaces, objects. Space is not an object, is the lack of matter. If you turn on a flashlight in a dark room you will illuminate the floors and the walls...

I have read that almost 80 to 90% of our space is made of dark matter or Dark Energy. But what is the function of this Dark matter or energy? Is this something that binds stars, galaxies, etc? If not then what is the actual matter with Dark energy?

I've been reading up a little on IC1101, the largest known galaxy and there is not a lot of info on it, but it seems to have an unusually large mass to light ratio according to this popular article (see half way down): According to this article at 20kpc it's got 12:1 mass to light, at 200kpc...