How the Universe Works (Today)

A 'Zero-Sum' Game of Cutting Edge Breakthroughs in Physics and Cosmology

While our best understanding of the cosmos is constantly evolving, there is a lot that we've managed to pin down. These things may be revised, or replaced, as our knowledge continues to advance; none of us can say for certain what the future will bring. For today, though, we will take a look at what we 'know' at this moment.

By definition, the universe is all that exists. It is the sum of all the matter, energy, and the lack thereof for as far as our best telescopes can see, and far beyond. It is all the stars, all the galaxies, all the light, and all the rest. It is the totality of everything.

Based on our best measurements, the universe is infinite in scope and scale. We know today that space can be bent and curved by the presence of matter (an effect called gravitational dialation), but that the universe as a whole shows no evidence of a general curvature. In fact, every test has yielded a result of zero, within the limits of experimental error, for the net curvature of the universe. This means that while planets, stars, solar systems, and even galaxies are held together by gravity's 'dent' in space (not 'Gravitons', as was previously believed: those don't exist), the universe has no such limitation.

To better understand, one might think of standing on the rim of the galaxy and throwing a baseball in a straight line along the edge. If such a person waited long enough, the baseball would slowly traverse the entire circumference of the galaxy, and return to the thrower from the other direction.

That happens because gravity, often mistakenly thought to be a direct 'pulling' force, actually reshapes space. Just like rolling a ball into a bowl, everything within its sphere of influence acts as if it were on a slope. Even light is affected.

This is not true of the universe in general. If one were to try the same experiment, one could wait forever, and the baseball would never return, because the universe has no such curvature.