> > However, I can't comprehend most of it because I can't get over how big the universe is. Not that this is anything new, or anything. But this fascinates, and more than a little scares me.
>
> The universe is far too big for anyone to really comprehend. We can grasp its hugeness with examples, like "if this grapefruit were our galaxy then the next nearest one would be on Mars," but we can't really wrap our heads around the truly immense distances involved. We live on a planet on which you can't travel more than 16,000 miles. That is our upper limit, and it's quite a distance. In astronomical terms, of course, that's nothing.

True -- even when I tell myself something like "I'm a dot in an aerial view of my hometown, it's a dot in an aerial view of the Pacific Northwest, the Pacific Northwest is a dot in a view of the Earth-Moon neighborhood, the Earth-Moon neighborhood is a dot in a view of the solar system, the solar system is a dot in a view of the galaxy, which is a dot in a view of the Local Group of galaxies, which is a dot in a view of the universe" it doesn't quite help me comprehend it.

Even APOD doesn't help, and it's a ruling site. If I feel like it later, I might dig up some relevant photos.

> Magnetic, gravitational, strong nuclear (holding atoms together) and weak nuclear (holding atoms to atoms). Some of them (I forget which) have been "unified", meaning that we now have fewer basic forces. At best, a grand unified theory could reduce this down to one. That still makes one mysterious force govern the interaction of all matter.

Just for the record: The electromagnetic force and the weak force have been unified, and that particular unification theory is the only unification theory that has been experimentally confirmed. (A grand unified theory has been proposed, but I believe it has not been experimentally confirmed yet, so it's not yet official.)

Lucky "At least, that's the status of the unification theory last time I checked." Wizard