Mingling with the masses [History of Physical Standards]

Would it be okay if I refer to mass as a weighty subject? And if I should do such a thing, would it give me gravitas? Well, weight and gravitas are much in the news these days, although weight seems to show up mainly in health stories and gravitas dominates the political scene. So let me be perfectly clear. Today, I want to discuss mass, weight, and gravity (the English equivalent of the Latin ??gravitas??).