Going Lightly
The designation "dark energy" for the something that constitutes the bulk of the known universe is clearly a placeholder. A permanent name for this fifth force of nature may await the determination of what exactly it is. All that seems to be known about it thus far is that it has a repulsive effect that is in some sense "the opposite of gravity." Whether this will prove to be its most distinctive feature once its full nature becomes known is anybody's guess (and certainly not mine, since I'm not a physicist). Should it turn out to be so, however, I propose that it be named "levity." Not only would this be suitable in its literal meaning (as the opposite of gravity), but it would also serve to lighten things up a little in a universe which heretofore has been dominated by gravity. So ... let there be levity! (I've been promoting this idea for many years, as witness a letter to the editor in Natural History magazine, which you can see by clicki...