I can't get over my excitement at today's announcement by the LIGO (Laser Interferometer Gravitational Observatory) team. If, somehow, you've missed it: a century after gravitational waves were first predicted as a consequence of Einstein's Theory of General Relativity, gravitational waves have been detected. Adding to the wondrousness of the announcement is that this particular detection also provides the first-ever direct confirmation that black holes -- another implication of General Relativity -- also exist.
And let's not forget the source of those tiny ripples: a cataclysmic event that happened 1.3 billion light-years from us! Two colliding black holes that, in a trice, converted into energy the mass of three suns!