[jwalsh07]

Also, I've read recently where the Big Bang can be explained using higher-dimensional physics (something like 11 dimensions in this particular branch of physics). The explanation was fascinating, but way above my paygrade and I'd make a fool of myself trying to reproduce them here.

Perhaps an explanation of dark matter which by Cosmologists estimates accounts for 70 to 90% of the Universe would be a better place to start.

Is there dark matter in our galaxy? Has any ever been observed??

[Doctor Stochastic]

Not directly observed. This has happened before. The neutron was hypothesized to explain atomic weights (inter alia) and the neutrino to explain beta decay (if my memory is correct.) At that time (late 1920s), there were two unobserved, but hypothesized, particles.