The Problem As I See It (Score 1)

I have comparatively little understanding of Physics (especially when you look at who wrote the original article), so I likely don't know what I am talking about, but here is the problem with finding GUTs as I see it. So far, Gravity has truly refused to budge and allow itself to be combined with anything. Yes, it seems to fit with the EM force, but unlike EM, gravity has no none particle of transmition. Scientists have hunted for but found no such thing as a gravitron. Personally, I doubt they will; this particle must be able to penetrate any and every substance known to man, else we would be able to construct a permanent anti-gravity chamber with materials alone. Not even the more powerful (read: high frequency) EM waves/particles can do that, as far as I know.
Also, if I am not mistaken, EM, weak nuclear and strong nuclear forces have all been united, and all have particles of transmision. I don't pretend to understand that unificaton nor do I even know offhand what the weak and strong particles of transmission are.
From what I understand, in an Einsteinian (is that a word?) way of looking at things, gravity is caused by a depression in space-time. Think of matter as a marble on a thin, stretched surface. The greater the mass, the larger the marble. Large masses will make depressions in the surface, as there is nothing to support the stretched surface. When you have such a depression, other marbles, especially small nearby marbles, will roll towards the marble. Larger or further marbles don't feel the effect of the depression as much; far marbles are on a relatively 'flat' region, and large marbles are in a depression of their own (read: have a large mass and inertia) and are not likely to move towards another large marble. The closer those two marbles are, however, the better the likeliness of them falling together, as their depressions become closer until there is just one larger depression.
Okay, so my analogy is a bit hard to explain. If I had something to show you, I could do it much better than in words.
Light interacts and is affected by gravity because of these depressions in space-time. Consider light to be a very tiny, extremely fast moving marbles on the stretched sheet (a photon has an equivalent mass because of its speed... don't ask me to remember what it is, however; all I know is it's very tiny). As they roll past a depression at high speeds, they are indeed turned by the depression, but not drawn in either; their high speeds keep them right on going, in a very slightly bent path. Einstein theorized this, and it was proven during a solar eclipse back in the early 1920s or sooner, even (for some reason the year 1917 pops to mind, but that could be just a guess).
So now you might ask, where am I going with this? Well, my point is this: gravity, to the best of scientists knowledge, works differently than the other three fundemental forces of nature (should that be Forces, now that I think of it?) The other three work on enough of a related basis (particles of transmission and other things beyond my comprehension), and gravity, as far as we know, has nothing else related.
One last thing. Someone better at physics can perhaps answer this for me. What exactly defines a fundemental force? There is so much that we think we know, but who are we to say that these, and ONLY these, are the fundemental forces of nature? What if gravity is just different, and does not fall into place no matter what we do? And what if there is another force we're not aware of? As unlikely as it sounds, we cannot say we know anything. And that is why I do not believe we will see a GUT by 2050.

Appologies if the post was confusing or if I contained incorrect information. Like I said, I know comparatively very little about Physics, but I do "know" that we always think we know something, and hundreds of years down the row we find out, "Oh wait, we were wrong. This is what's really true." We can never say we know everything.
- Harukaze, a rambling moron:)