Dark Matter: a layperson's theory why 90% is unaccounted for

Dave Zak

Dark Matter: I am not very schooled in physics or cosmology and have not read much about dark matter but I do see that scientists are curious about the subject of dark matter. Perhaps the dark matter is just planets and other debris that does not produce light. By calculating the mass of all known planets, moons, asteroids, meteors and dust in our own solar system and comparing this to the mass of the sun, do you think that it may surpass the sun's mass by 90 percent? The articles that I have read state that approx 90% of the universe is unaccounted for (Hence the theory of dark matter) By using our own solar system as a microcosm to compare to the rest of the universe, we may find that this percentage holds true in our own system. Obviously I am a lay person with very little knowledge about the subject and I'm sure that Scientists have already looked at this, but it doesn't hurt to ask what the percentage of mass is in our solar system that does not produce light. If the percentage is much less than 90% than we can consider the possibility that black holes account for the rest (obviously there are no black holes in our solar system to add into the equation) Another Thing to consider is that stars, although very large, seem to me to be made of the lightest of materials(hydrogen and helium) and planets tend to be made of "HEAVIER" Matter such as seen in earth(our core made up largely of iron) If this is the case, stars would be what we see most often but would really only account for very little of what actually exists. Am I an idiot who hasn't done his homework? I just recently took up an interest in the big bang, black holes, and dark matter. If I am an idiot, please let me know politely. Thanks. WAIT!!! There's more... I viewed a 3D model of the milky way galaxy at the following address (http://lambda.gsfc.nasa.gov/product/cobe/milky_way.wrl)
and noticed that we (earth and our solar system) are located in the outermost region of the galaxy. Could it be that planets and other non luminous objects are more likely to be located on the outskirts of a galaxy as heavier matter would have more centrifical force and shy away from the center? My thought would be that the heavier materials would break away from the center and therefore the center of a galaxy would be mainly gasses and whatever unfortunate heavy metals that did not escape being engulfed by the numerous stars in the center. Therefore, in my train of thought, most planets would be located approximately in the same orbit as us around the galaxy or perhaps even further out. If Space is essentially a vacuum and light travels for infinity until it is absorbed by obstructing matter, wouldn't it make sense that the further the galaxy, the less liklihood that we would notice it. And if heavier, nonluminous matter, did in fact exist on the outskirts of a galaxy thereby blocking what we see, wouldn't it be sufficeable to say that many galaxies are not observable due to the planets and asteroids that suround them? Think about it. If you go to NASA' s website and view the hubble photographs of the most distant galaxies you will notice that galaxies which are seen as spirals (which are the minority--- many galaxies appear as a thin line due to their tilt) are perpendicular to us and very visable because galaxies tend to be flat. Those galaxies would have their heavier, non luminous materials on the outskirts like I theorized, but because we are viewing them perpendicularly, the matter that would normally dim our view does not get in the way. If my observations held true, than at least half of all galaxies would not even be observable to us because we are looking directly at their edge (the edge being primarily nonluminous matter that blocks the light from ever reaching us) Do you think this could explain why scientists have not been able to account for 90% of the theorized mass of the universe?

Philipum

Yes, it is true that at least part of the missing mass might consistof gazes, dust or other non-luminous bodies that we don't see between the galaxies: look at the link on the left: there is an article in nature about that!
http://www.keepmedia.com/pubs/AFP/2005/02/03/717689

Observe that our Sun is one thousand times heavier than Jupiter which in turn is three hundred times heavier than the Earth. Stars are much heavier than planets and that's why we use to believe that most of the mass in the galaxy should be visible; else we would need to have thousands times more planets than stars, and that remains to be observed! Scientists in the hunt of dark matter candidates try to obseve short occultation of star light, ovserving thousands of stars at the same time. If we see the light disappear and reappear for a short time, it means that some big planet (called "matcho") passed between the star and us: that way it is possible to put limits on how many of theses big planets there are in the galaxy.

But you say that you believe there would be planets at the edges of galaxies. Why not? We observe that there are belts of comets at the edges of the solar system; maybe the same thing happens around galaxies!

ma1999

A good one.

But the problem with stars are that they are so much bigger than anything else in their starsystems. Sure a rocky planet has a bigger average density (5-6 compared with 1.4 for the sun) but the Sun is almost 400.000 times heavier than earth.
In our solar system we would notice huge unaccounted for objects.
On the edge of galaxies, or in "empty" space. I dont really know. Huge masses must affect other masses with their gravity but since the effect is there who knows what amount of black holes there are out there.

absolutly

I am also a layman of these concepts and I do not claim to know everything there is know about what has already been discovered. However, after thinking about everything I have learned in my college classes and on the science channel, could it be that dark matter is not matter at all? Maybe it is just a force acting on neighboring galaxies around what we think of as dark matter? Let us take into account that it is possible that the center of our galaxy and every other galaxy in the universe is a black hole. I don't know how much of a stretch this is, but let us say that it is a given.

Black holes from what I understand have very very large gravitational fields. So large that not even light can escape. This force acts like a small but very heavy marble in the center of a very large trampoline. On the bottom (and upside down) of this trampoline you would see not a funnel, but a peak. It applies a force all the way to the peak of it which is what determines its shape. What if that peak is so large, that it applies its energy to anything in its way. Could it be that this energy is applied to neighboring galaxies, or maybe even across the universe? I don't remember who theorized this (Hawking?), but someone was quoted as saying the end of this funnel in the center of where blackholes lie may turn up some where else in the universe. If this is true, maybe that is what dark matter is, not matter as we know it but just a force that acts as all forces do. Since we cannot see force acting on an object, to me it seems that the dark matter is not an object (matter), but rather a force that is applied from an object we simply do not know the origin of.

Imagine a sphere that has points on it which represent bodies of mass like our galaxies. The sphere is there as a result of the big bang, and it is constantly expanding even though there is nothing in the center acting on it to make it larger. What if those bodies of mass (galaxies) are not attracted to each other, but rather they repel each other due to the nearly inifinite mass in the middle of them, maybe even on the other side of this "sphere" we call our universe? Its a hard concept to think about, but that could account for the "self-perpetuating" nature of the expansion of the universe. Plausible?

Philipum

I like your attitude. Everybody is trying to find some hypothetical dark matter while there is still so much we don't understand about what we call gravitation. Supposing unknown types of forces at large scales, as you do, makes sense to me! It makes at least as much sense as supposing new types of particles or interstellar objects.

I have my own (simplistic?) hypothesis for the dark matter problem. I believe the missing mass is in the gravitational field. In analogy, if you excite a nucleus, it becomes heavier because the excitation energy is equivalent to a mass; the same thing happens when you excite the electrons of an atom, but then the additional mass is negligible since the electromagnetic force is much weaker than the strong force. If this is valid for the strong and electromagnetic forces, why wouldn't it be the same for the gravitational force? I believe that the Earth-Moon system is slightly heavier than the sum of the Erath and Moon masses, because it is gravitationnaly excited: if the Moon falled down onto Earth, the energy gained could in principle be converted into mass, and what I am saying is that this mass is there all the time. For the objects inside the solar system, this additional mass is negligible (cannot even be detected), but I suspect that at a galactic scale, it plays a significant role.

Dark Matter: a layperson's theory why 90% is unaccounted for

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