Engineering News

Seems to me this could also be caused by unknown black holes...

Assuming for a moment this were the case, their mass-distribution would have be extraordinarily homogeneous as compared to that observed in other types of (baryonic) matter throughout the same given volume of space. And whilst black holes are themselves 'dark', any infalling matter is not and such would betray their presence in, say, regions rich in dust and gas such as galactic arms and stellar nurseries. These would be seen as being bathed in a background of hard x-rays (assuming the black holes were numerous and small), but this has not been observed generally. Explaining the required mass distribution is most problematic and would raise its own issues; possibly even greater ones than "what is dark matter?"

Could you possibly say nothing with zero words, please.

Well, in that case, have you tried Facebook?

No doubt.

Jan,

Why would you make such a statement? What is someone were crazy enough to believe you were holding extremely valuable information?

What would keep a group like that from picking you up in South Fork to extract the information? What if they assumed you would be a tough cookie, so also picked up Tina, not too far from you, and also Buddy and Debbie (whle they were out on a motorcycle ride in Georgia)? Even if you are still mad at Gregory, his well being might motivate you to disclose information...

.

...and what then? What if your captors were unconvinced that what you told them was valuable or true?

.

Aside from reckless endangerment of yourself and loved ones, isn't your boastful and prideful action (proclaiming you have received special knowledge) a sin in your religion?

.

'Better to keep your mouth shut and be thought a fool, than to open it and remove all doubt'.

Thanks for this advice

"'Better to keep your mouth shut and be thought a fool, than to open it and remove all doubt'."

It may be 50 some posts too late.

Thanks for this info and your both absolutely correct! And again many thanks!

Sorry, I think you have a slight typo.

I think you meant "absurdly correct". :)

Sounds like a plan. Mum's the word.

Try switching to decaf.

You keep saying that you tease monkey you!

No surprise but the article mentions nothing about why other theories have been proposed. The glaring unsolved complication to dark matter and dark energy theory is that about 70% of the universe must be dark energy, 25% must be dark matter and the 5% remaining is the only part we can directly detect to match our distant observations. (SE black holes are part of the 5%) Dark matter and energy are just as directly detectable as angels and fairies. The alternate theories of MOND and others try to explain observed distant phenomena utilizing known observable matter and forces. One of the MOND proposals is that gravitational forces asymptotically approach a tiny finite value and not zero as the distance reaches infinity.

All of these theories fall apart and do not explain one phenomena or another. That is why new research happens. Nobody knows which existing theory if any will ultimately be the last word.

I have 2 problems with this article.

The first is the general statement that 'One graph' makes the entire case for one point of view. C'mon, anyone who has made a graph -- you know, like astrophysicists and other scientists -- know that graphs can lead to one conclusion or another, depend how the person chooses to plot the data. Here's a dummy graph to illustrate the point. The same data is plotted in 2 different graphs, but by choosing the scale of the graph it can be made to look like the RMS slope is 1 or 0.3. (Gee, data can be manipulated to enhance one point of view -- who knew?!)

The other problem with this is the flawed logic that because a previous problem with an earlier version of the law of gravity was 'fixed' by finding a missing mass, i.e., a 'real' visible mass - the planet Neptune, therefore the same fix will work by invoking another missing mass, in this case dark matter - except this mass isn't visible. It's also not 'real' in the same sense that Neptune was real. Neptune was just another planet that hadn't yet been spotted; dark matter is not simply another galaxy or two that haven't yet been spotted. If the observations are right, then dark matter is a HUGE chunk of matter many times larger than the stuff we do see, that we've overlooked. [By his analogy, Neptune was a black planet 5 times the size of the Sun.]

One graph may not prove a claim, but it is all that you need to disprove a theory, if that evidence is valid.

Dark, unobservable, but gravity producing this or that is undistinguishable from black magic that shows up at opportune times to save the bacon of some halfbaked ideas.

At this time - I for one - fail to see any difference.

Now, if any measurements would show up.....

In the meantime, if properly uninhibited, I can throw some ideas on paper.

???

I was talking allegorically, or was it something else only Shakespeare would appreciate?

Actually, I miss the good old, almost discovered and shunned, 5th and 6th forces from the new theories.

As an aside. Recently I read a note stating, that measuring 400 individual star's speeds there was no deviation from classical movements. Hence: would it be possible, that bulk measurements have built-in bias? Nah, bias? Only my mind in overtime.

Ah.

Cool! Using the motion of the planets in our solar system to definitively establish the existence of Dark Matter! Yea!

..

...wait a minute. I don't see anything in here detailing the gravitational effects of Dark Matter on the motion of the planets. Real matter is supposed to comprise only a small fraction of the universe, certainly there must be some dark matter around here somewhere. Shouldn't it be affecting the motion of the planets/solar system?

It is, actually - the Solar System is not adrift in intergalactic space along with every other star system in the Universe. Instead, we're all largely bound up into galaxies and whatnot. As for our Solar System, it is also bobbing up and down through the Galactic Plane a bit faster than seems proper, given the *observable* distribution of mass in the neighborhood. Funny thing about dark matter is that it doesn't seem to clump together like ordinary matter. No dark matter planets, stars (bye bye dark mystique!) etc., etc. Weird, huh? Lots of it there, evidently, but not concentrated to the point where it perturbs orbits to much degree. Weird stuff - if it exists at all and isn't really some other, large-scale-only feature of spacetime that we haven't guessed yet. The Universe is "mostly" dark matter, but when you consider how empty space really is - even with the addition of dark matter - you can appreciate why the planets aren't affected to any observable degree. To get an Earthly-scale idea of this vast emptiness, consider that if you placed three grains of sand in the Notre Dame Cathedral, the N.D. would be more densely packed with sand than space is with stars, in our stellar neighborhood. Add seven more grains and you've accounted for the density of dark matter in same.

Nice analogy in the volumes of space. I like it. Another analogy I remember from long ago on the known mass of just the solar system is like this. Take a bag of 1000 marbles for all of the known mass of the solar system. Take one marble out of the bag for the mass of Jupiter and all of the Jovian satellites. Take another marble out of the bag. The second marble is the rest of the solar system and the bag is the mass of the sun.

Getting back to the topic of dark matter. I heard a few ideas floated for discussion why we who manipulate and measure the universe with baryonic matter cannot directly detect dark matter.

Dark matter can only apply a force only with the matter being changed into energy. Thus only the stars themselves (the 99.8% of our solar system) are influenced by dark matter. This concept implies a large force on far fewer particles for only a tiny percentage of the sun is being converted to energy at any moment in time.

Another idea is the bubble idea that our solar system happens to be in a dark matter void. To apply your cathedral analogy, the seven grains of dark matter are dust particles in the hall evenly dispersed while our solar system is a grain in the hall. This bubble condition could be purely a coincidence of time and one day a dust particle may float by or through us. It may even be that this bubble is some how an established attribute of our local, thus dark matter cannot exist in our corner of space to be directly detected.

Both of these ideas and the ones I haven't presented all have problems. The existence and total attributes of dark matter are far from certain. At the same time dark matter is our best explanation of how the universe works. This is how we grope for Schroedinger's cat in a dark room. Unlike Schroedinger's binary state problem of alive or dead for this cat; we don't know if a cat exists, if it is willing to be touched, or even how large is the dark room.

Why would a theory single-out only baryonic matter that is being converted to energy? In the Sun's case that amounts to only a few-to-five million tons per second, requiring such a force to be enormous indeed! Five million tons per second is practically zip by stellar-mass standards. What is their thinking?

For my part I'm wondering if we're not really dealing with far more ordinary, albeit hard-to-detect variant(s) of neutrinos. Practically massless, yet nearly every nuclear process produces them, some copiously. 13.75 billion years of *that*, plus those produced in the BB, and three generations of stars later you can bet there's gunna be a huge buttload of 'em everywhere. Nor would they clump, but WOULD tend to be associated with higher concentrations of baryonic matter like we're ascribing to the presence of dark matter.

Another thought just struck me - consider the photons making up the CMB. How did they start out? Not microwaves to be sure! Gamma rays, X-rays, etc. Short-wave Stuff, yes? What about particles of matter making this same trek? Neutrinos. Gobs of 'em. Protons, electrons, you name it, blasted throughout space along with everything else, but neutrinos especially. Zipping along only slightly behind their photonic brethren, interacting with nothing essentially, with the fabric of spacetime being stretched out from under their little neutrino feet. Stretched photons? Sure. Stretched neutrinos? Why not? It's all mass-energy. What does the Universe care? Hey, what's good for the goose is good for the gander. What would a stretched elementary particle be like? Matter whose own wavelength, like that of those CMB photons, 'smeared' over spacetime itself? Like anything we've ever seen?

I too like the idea that neutrinos constitute the majority of dark matter and that most of them come from the vast number of nuclear processes that happen in the formation and continuation of our universe. The point of the theory singling out matter transforming to energy is that it explains why planet trajectories and terrestrial experimentation cannot reveal what and where is 3/4 of the matter in the universe. The mysterious force directly imparts onto the light producing part of a solar system. This does answer the question of if it is hard to directly detect then how can it be a dominant effect on stellar motion?

Thank you Europium. I often find your comments to be helpful/thought provoking. This is no exception.

Europium:

It seems like something that acts on mass in a way that causes mass to be more clumpy, while at the same time, is itself not caused to be clumpy; suggests some very strange physics...

...doesn't this situation imply action without equal and opposite reaction?

I appreciate your thoughts on the subject.

Molto apprezzamento! Grazie!

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Oh! I remember; you prefer Kannada!

ಮೆಚ್ಚುಗೆಯನ್ನು ಹೆಚ್ಚು. ಧನ್ಯವಾದಗಳು!

First I have much to say about nearly nothing and inevitably it would definitely and miraculously open many, many locked doors for sure. As of now one just wouldn't believe? Not only this but it would save an immense amount of valuable time in heading towards the correct direction. Also From your brief synopsis of wee hrs in the morning (Am) (but also night time) and pointing southward at the sun I'm going to chance it and make the statement your either nearer the South Pole or the North (More than likely North). Also given the fact of your title europium one must be from thereabouts somewheres as well in given locations?

Andromeda. Earth's coincidental transit across the face of your star merely made the example convenient. That it was dark here at the time (and in what might be called our 'Northern Hemisphere by your reckoning - but you wouldn't know merely by looking, given our dense ammonia/methane atmosphere) was true by virtue of our our three suns having just set - another convenient coincidence which merely gave the *appearance* of my writing from your world. Your left shoe is slightly untied, by the way...

Which left foot?

The Other One. :-)

Not as untied as one would have another believe regarding anyones left shoe! Even as protectioms of a sort must remain in place!

Those, too, have been noted and duly logged. Verily.

Excellent post!

This explains the dark matter at the bottom of my pool and why it just blows right through my filter.

As stated in #6, #8, I for one are amused by, and little use of less than halfbaked ideas, that are not distinguishable from black magic.

I came accross a few, not needing sleight of hand. These are measurements, proveable or disproveable. As it should be.

A study measured 400 individual stars in other galaxies too(I think), and came up with good old Newton standing alone.

Another study used radio interferometry -and was published a few years ago in Scientific American too, I think - took an unprecented close look at the center of our own galaxy. In a tiny area stars were accelerated to relativistic speeds, and spun around an invisible point = black hole. Newton + relativity stood alone.

Another study, somewhat speculative, found some reason to invoke a huge halo, 1000x - 1million times larger that its host around galaxies. Very, very thin by any standard, extremely energetic (high temperature) normal particles. Their total mass influencing gravity in the galaxy. Earth telescopes cannot detect them thru the filter of the air. The satellites already built do not look for them. OK, so far. At least they propose something testable. No black magic invoked.

Considering, how much new was learned in a lifetime or two, that was real, I have little use of convenient sleigh of hands.

Discoveries do not come always fast or linear. In the 1930's Wolfgang Pauli proposed the existence an unseen particle, Neutrino, to satisfy energy conservation laws. It did fit there well, but for decades, it, now they were not seen. Even today there is an ongoing debate about their attributes. Some are spooky, but not magical, as of yet.

I always wonder if Dark Matter/Energy is just today's version of the Luminiferous Aether.

Luminiferous Aether was a convenient way of describing how light waves can propagate through a vacuum. This is necessary because waves must have a medium and Aether provided a convenient explanation.

Dark Matter theory produces an equation for a line which fits the observed data, but that doesn't prove anything. Math may be used to describe reality, but it is not reality. (A. Einstein "As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.") I am sure there are an infinite number of equations which may be found to fit the data, but they are just equations.

Dark Matter may yet fall to its Michelson-Morley analog.

Dustin Hoffman, at his graduation party, when an obscure Cosmologist walks up, drink in hand, and gives him a word of advice: "Phlogiston"

I agree. This is why I like MOND and other theories because it tells me that sharp minds are not blindly accepting any doctrine.

When people get become fixated on the math that "proves" something, I always remember two examples which keep my skepticism healthy. First is that Einstein quote. The second is from a Math professor I had in college.

One time, the class somehow turned into a discussion of standardized tests which ask you choose (multiple choice; A,B,C,D) which is the next number in the sequence of the four numbers given. The Prof scoffed. "There is no right answer." He demonstrated this by asking the class to give him four numbers (try this next Improve night at the Comedy Club). He then listed out A, B, C, D and put a number by each and ask the class which was the right answer. Then he'd show us the formula he used for each number. That is, every number was the next number in a sequence, depending on which formula you chose to use.

"...sharp minds are not blindly accepting any doctrine."

Do you find it really, really annoying when you meet one who does? I do.

Years ago I was under contract to develop the data-acquisition software for a new kind of ion detector used on mass spectrometers. A researcher at MIT's Scripps Center for Mass Spectrometry had come up with the idea and it was a good one - very sensitive and fast, allowing mass spectrograms to be taken of extremely minute samples: ten femto moles (roughly what sticks on the outside of a mosquito's snout after she bites you). Thing was, there was a screen over the active area to catch the low-energy electrons which 'splashed' up when the ions struck the detector. If these weren't caught and removed, they'd fall back onto the detector, manifesting in the spectrogram as 'shoulders' on either side of peaks and obscuring what might otherwise be seen there. The screen was the solution - except that, where the screen's wires crossed the detector, there were shadows. The wires were tiny, but to ions (even the 60,000-dalton monsters we were studying) they were like a superhighway compared to a BB. I offered to remove the screen, leaving only the retaining ring (also at the screen voltage) to capture the electrons. They wouldn't have it. This was the famous _________'s design from MIT! How dare I consider such a thing? How? Easy. It was a problem, and it needed fixed, and fast. We were under a deadline.

Solution: wait until the buggers went home, opened the thing up, pulled out the screen and put everything back. Next day, no shadows. They were thunderstruck (I love that word, thunderstruck?). "How'd you do that?" they asked. "Took out the screen." "What?! What'll ______ say?" "Stop kissing that bloke's arse and start thinking on your own for change, k? It's a really bad habit you know? Not thinking? You want your shadows back? Ten minutes."

(sigh)

I've been on the other side of your story. We developed a sweeping monochromator from a collection of spare parts. This included a servo loop controlled motor that was a little undersized for the driver. It was intended to be just a proof of concept so I never did a full mechanical analysis in all positions. The experimenters were so pleased that they could do quick catalysis of intermediate reactant stages that they ran the experiment as is. Eventually a post-doc that had never heard of control theory decided he wanted this sweep to be wider and faster. The first couple of unauthorized tweaks were successful. Eventually he put a couple of poles somewhere in the right hand plane... whrrr, clunk, pop, smoke. Thank goodness the beam line had a beryllium window. Got my funding for a real upgrade.

Sweet!

At MIT's AI lab for years there was a little robot they called Shaky. One day it was decided that Shaky had earned their trust to where he could handle the responsibility of an RF link. Shaky's tether was removed, allowing him to move more freely through the lab. Free! Free at last! Thing was, nobody changed Shaky's software to reflect the fact. Puzzled students finally complained that their code seemed to work fine except that, every so often, Shaky would inexplicably drive to the middle of the lab and spin around a few times, then resume executing their instructions, as before. They pored over their code, looking for the problem, but to no avail.

Seems Shaky didn't quite understand that RF links didn't need to be untwisted after so many turns, but nobody bothered to explain that to him. And besides, after doing that for so many years, it had become a bad habit.

Everyone is just trying to explain an observation.

Dark matter was simply a mechanism to hang one's hat until an explanation for what is observed is accounted for.

It isn't much different than dark energy in that regard. The same goes for supersymmetry, although, supersymmetry appears to now have some major chinks in its armor after the discovery of the Higgs.

Not quite. Super-symmetry is the application of some purely theoretical set theory mathematics (I cannot think of a way around that redundancy) to originally observed and now fabricated collection of fundamental physics particles. The consistent ability of this unexplained mathematics relationship to predict particles prior to detection does beg the question why does this mathematical theory relate so well to particle physics? One underlying theory proposed is string theory. Unfortunately for string theory (depending on who you talk to) the mathematics is so complicated and convoluted that testable predictions are hard to agree on the prediction, let alone a test for the prediction. Super-symmetry is apparently a solution set of string theory but clearly not a unique solution.

At least this is the concepts I get of Super-symmetry and string theory from reading "Not Even Wrong" by Peter Woit.

"All models are wrong, but some are useful"

-George Box

Thing about George, he never thought outside the Box. (groan)

...except when he was out of his mind. (double groan)