HEIC: Dark Matter Even Darker Than Once Thought

[bystander]

Dark Matter Even Darker Than Once Thought
ESA Hubble Science Release | 2015 Mar 26

[url=http://www.spacetelescope.org/images/heic1506h/][b][i]Collage of six cluster collisions, with dark-matter maps and X-ray data[/i][/b][/url] [b][i]Credit: X-ray: NASA/CXC/Ecole Polytechnique Federale de Lausanne, Switzerland/D.Harvey & NASA/CXC/Durham Univ/R.Massey; Optical & Lensing Map: NASA, ESA, D. Harvey (Ecole Polytechnique Federale de Lausanne, Switzerland) and R. Massey (Durham University, UK)[/i][/b]

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Astronomers using observations from the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory have studied how dark matter in clusters of galaxies behaves when the clusters collide. The results, published in the journal Science on 27 March 2015, show that dark matter interacts with itself even less than previously thought, and narrows down the options for what this mysterious substance might be.

Dark matter is a giant question mark looming over our knowledge of the Universe. There is more dark matter in the Universe than visible matter, but it is extremely elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible Universe (heic1215a).

To learn more about this mysterious substance, researchers can study it in a way similar to experiments on visible matter — by watching what happens when it bumps into things. For this reason, researchers look at vast collections of galaxies, called galaxy clusters, where collisions involving dark matter happen naturally and where it exists in vast enough quantities to see the effects of collisions. ...

Dark Matter Is Not as Sticky as Once Thought
NASA | STScI | HubbleSite | 2015 Mar 26

Dark Matter is Darker Than Once Thought
NASA | MSFC | SAO | Chandra | 2015 Mar 26

The nongravitational interactions of dark matter in colliding galaxy clusters - David Harvey et al

• Science 347(6229) 1462 (27 Mar 2015) DOI: 10.1126/science.1261381
  arXiv.org > astro-ph > arXiv:1503.07675 > 26 Mar 2015

[FloridaMike]

So, ... How ... dark .... is it!

[Ron-Astro Pharmacist]

So, ... How ... dark .... is it!

It's sooo dark, it doesn't matter!

[FloridaMike]

So, ... How ... dark .... is it!

It's sooo dark, it doesn't matter!

OH, It matters... It's just not something you can reflect on......

[Ron-Astro Pharmacist]

So, ... How ... dark .... is it!

It's sooo dark, it doesn't matter!

OH, It matters... It's just not something you can reflect on......

I rarely miss an opportunity to reflect on it - it's sooo interesting. I also rarely miss an opportunity to apostrophe those words that "matter" but I did post before last. I wish they could have foreseen the future when they named dark matter. Wonder what might be a better term?

Unseen matter?

Not matter sounds ungrammatical while no matter seems uncaring. I think where stuck with the dark stuff. I kind of wish it'll turn out to be "hyper" matter but wouldn't bet on some multi-dimensional imaginary material.

[Chris Peterson]

I wish they could have foreseen the future when they named dark matter. Wonder what might be a better term?

"Dark matter" is pretty good, since it is primarily categorized by its lack of interaction with the electromagnetic force, and electromagnetism is the thing that humans are predisposed to associate first and foremost with light.

[neufer]

I wish they could have foreseen the future when they named dark matter. Wonder what might be a better term?

"Dark matter" is pretty good, since it is primarily categorized by its lack of interaction with the electromagnetic force, and electromagnetism is the thing that humans are predisposed to associate first and foremost with light.

[b][color=#0000FF]Map of North America from 1566 showing Italian inscriptions, both Terra In Cognita and Mare In Cognito[/color][/b]

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<<It has been noted that the names "dark matter" and "dark energy" serve mainly as expressions of human ignorance, much like the marking of early maps with "terra incognita".>>

<<Terra incognita or terra ignota (Latin "unknown land"; incognita is stressed on its second syllable in Latin, but with variation in pronunciation in English) is a term used in cartography for regions that have not been mapped or documented. The expression is believed to be first seen in Ptolemy's Geography circa AD 150. The term was reintroduced in the fifteenth century from the rediscovery of Ptolemy’s work during the Age of Discovery. Similarly, uncharted or unknown seas would be labeled mare incognitum, Latin for "unknown sea".

An urban legend claims that cartographers labelled such regions with "Here be dragons". Although cartographers did claim that fantastic beasts (including large serpents) existed in remote corners of the world and depicted such as decoration on their maps, only one known surviving map, the Lenox Globe, in the collection of the New York Public Library, actually says "Here be dragons" (using the Latin form "HIC SVNT DRACONES"). However, ancient Roman and Medieval cartographers did use the phrase HIC SVNT LEONES (Here are lions) when denoting unknown territories on maps.>>

[Ron-Astro Pharmacist]

That it doesn't interact with electron-magnetism, hence light, is one of the reasons I potentially view dark matter as something extra-dimensional. I suppose that's from reading the fictional accounts of one and two beings unable to think of living in or with the next dimension "up". I can "see" electricity as one dimensional (points), magnetism as two dimensional (planes) with the addition of light (spherical from its source) extending the previous two to three dimensionality. If something were to exist in a 4th dimension it might influence the three dimensions, we can sense, in peculiar ways potentially explanatory. Purely conjecture at this point obviously.

I've tried watching videos of individuals who seem to think they can visualize a 4th dimension but it has not yet crept into my mind comprehensibly. Until then I might have to think of it as – that "darn" matter. It's just too tempting to think that a 4th dimension would explain some of the mysteries of quantum mechanics and the unusual characteristics of light acting both as a wave and a particle.

Art might be best describing my thoughts as the early map-makers trying to make a map of something best viewed in totality rather than from the pieces and parts. Maybe it's hopeless but you have to admit it keeps our interest and it drives me on my "learn-on-the go" scientific method. Think of a new concept then go back and review everything previous to that – and see if it fits. Talk about back-assward but it keeps me entertained for now.

Talk about being off topic. I'll have to claim I thought it meant "Destroying" Science News.

[Chris Peterson]

That it doesn't interact with electron-magnetism, hence light, is one of the reasons I potentially view dark matter as something extra-dimensional.

Do you look at neutrinos that way? Neutrinos interact only through the weak nuclear force and gravity, just like WIMPs, the most popular dark matter contender. The main difference between the two (in terms of interaction) is that the neutrino has an extremely low mass, while a WIMP has a high mass (similar to a neutron, perhaps), so its gravitational effects are much more apparent than that of neutrinos (which is too weak to be directly observable).

[Ann]

I'm sure I have read somewhere that there is speculation that the weakness of gravity itself compared with the other fundamental forces might be that gravity could be leaking into our universe from something or somewhere outside our universe.

Of course, just because I remember it doesn't mean I necessarily remember correctly. And even if I remember correctly doesn't mean the speculation itself is necessarily warranted.

Ann

[neufer]

I'm sure I have read somewhere that there is speculation that the weakness of gravity itself compared with the other fundamental forces might be that gravity could be leaking into our universe from something or somewhere outside our universe.

<<In particle physics, the ADD model, also known as the model with large extra dimensions (LED), is a model framework that attempts to explain the weakness of gravity relative to the other forces. This theory requires that the fields of the Standard Model are confined to a four-dimensional membrane, while gravity propagates in several additional spatial dimensions that are large compared to the Planck scale. The model was proposed by Nima Arkani-Hamed, Savas Dimopoulos, and Gia Dvali in 1998. Results from the Large Hadron Collider do not appear to support the model thus far. However the operation range of the LHC (4 TeV) covers only a small part of the predicted range in which evidence for LED would be recorded.>>

• http://home.web.cern.ch/about/physics/e ... lack-holes
  http://www.pbs.org/wgbh/nova/blogs/phys ... -weakling/

[Ron-Astro Pharmacist]

That it doesn't interact with electron-magnetism, hence light, is one of the reasons I potentially view dark matter as something extra-dimensional.

Do you look at neutrinos that way? Neutrinos interact only through the weak nuclear force and gravity, just like WIMPs, the most popular dark matter contender. The main difference between the two (in terms of interaction) is that the neutrino has an extremely low mass, while a WIMP has a high mass (similar to a neutron, perhaps), so its gravitational effects are much more apparent than that of neutrinos (which is too weak to be directly observable).

I have been listening to too many video lectures and not spent nearly enough time learning from actual professors that would squelch my view of "how" the universe is. One main point that does seem relevant is that chemists continued to use the term atoms when describing matter. While I was off yesterday, I was re-viewing Sean Carroll's "Beyond the Higgs Boson" which he was reiterating the fact atoms really don't exist. They are only the result of strongly interacting fields. He was claiming we really aren't viewing a world of atoms but merely a whole lot of interacting stable fields.

The weakly interacting particles such as neutrinos, I suppose, in my "hyperspace" universe would have fields that only very infrequently interact with stable fields. I couldn't begin to define how that would occur in a 4th dimension bit if you compare it to something on a 3 dimensional graph, it might only occasionally cross coordinates while stable particles frequently lie on or close to the coordinates. (if it is true our observable universe is only a patchwork of fields)

I still haven't given up the idea that gravity is a remnant of the expanding universe and we all sit on its outward boundary only seeing the universe as we do because everything is equa-distant from the moment of the big bang or whatever initiated the universe we see. Larger groups of particles interact with nearby smaller groups of particle only because size and expansion forces them to remain in proximity. And I still wonder if the Higgs field isn't a possible source of the expansion.

I'll never be able to prove any of this because I'm my math education ended with early calculus long ago and my physics is non-existent. I don't suppose you could derive each masses hyperspace as a function of its individual volume? The boundaries of its hyperspace would at least be definable. For instance the Earth's hyperspace based on its volume 4/3πr3 would be 4π4 + C if I remember the process correctly. Told you it was long ago.

I'm only left with woefully inadequate guessing but I am lucky enough to have found a place to imagine out loud. My condolences to all of you who choose to read this – you probably just rolled snake eyes but thanks for taking the time.

[geckzilla]

I'll never be able to prove any of this because I'm my math education ended with early calculus long ago and my physics is non-existent.

Why are you doing this? You know you need more education in order to understand all of the knowledge someone like Sean Carroll has accumulated in order to make the kind of statements he makes, but you insist on trying to intuit something as unintuitive as quantum physics.

[Ron-Astro Pharmacist]

I'll never be able to prove any of this because I'm my math education ended with early calculus long ago and my physics is non-existent.

Why are you doing this? You know you need more education in order to understand all of the knowledge someone like Sean Carroll has accumulated in order to make the kind of statements he makes, but you insist on trying to intuit something as unintuitive as quantum physics.

Thanks for your guidance Geck. As I said in my PM - your job is a tough one. To help the unenlightened navigate a sea of ignorance with a gale of over-enthusiasm blowing their minds. Well, I didn't say that but it's the truth. Ron

[Markus Schwarz]

One main point that does seem relevant is that chemists continued to use the term atoms when describing matter. While I was off yesterday, I was re-viewing Sean Carroll's "Beyond the Higgs Boson" which he was reiterating the fact atoms really don't exist. They are only the result of strongly interacting fields. He was claiming we really aren't viewing a world of atoms but merely a whole lot of interacting stable fields.

Such statements do more harm then good! Technically, what Sean says is correct. "Atoms" in the original 19th century sense, meaning parts that you can no longer break apart, don't exist, because we now know the constituents of atoms. But that does not make the concept of the atom obsolete. Chemistry works and is based on atoms. And for the record, physicist are still unable to calculate basic properties of atoms (e.g. energy levels) more complex than hydrogen. So, a physicist saying that "atoms don't exist" is highly confusing.

[Ron-Astro Pharmacist]

One main point that does seem relevant is that chemists continued to use the term atoms when describing matter. While I was off yesterday, I was re-viewing Sean Carroll's "Beyond the Higgs Boson" which he was reiterating the fact atoms really don't exist. They are only the result of strongly interacting fields. He was claiming we really aren't viewing a world of atoms but merely a whole lot of interacting stable fields.

Such statements do more harm then good! Technically, what Sean says is correct. "Atoms" in the original 19th century sense, meaning parts that you can no longer break apart, don't exist, because we now know the constituents of atoms. But that does not make the concept of the atom obsolete. Chemistry works and is based on atoms. And for the record, physicist are still unable to calculate basic properties of atoms (e.g. energy levels) more complex than hydrogen. So, a physicist saying that "atoms don't exist" is highly confusing.

Good point Markus. You have to consider the source too - me. Sean Carroll, in those videos I was referring to Democritus coming up with the term "atoms" and the 20th century chemists adopting the term. Carroll was just saying it was an unfortunate choice of terms – not that they don't exist. I believe he was trying to communicate a term like "particle" would have been a better choice to describe their complex and unintuitive makeup.

Always wise to refer to the original source though - especially when the secondary sorce claims his ignorance up front. Thank you for the clarification. Ron