My view about the "A", Conchita clearly connects it to the sky, although the example with two stars colliding is an example. Whether it is an Asteroid, or something else, I don't know (I don't know Spanish). It is obvious it cannot be Annunciation or anything similar. We do not know what exactly will make or consist the Great Warning (I can't find the correct word, sorry), while we are told of its effects on the consciences. It is clear from the interview Conchita does not deem it necessary to say it. Maybe because it won't be accepted by otherwise devote people who are not prepared for it? Just a guess. While the danger of "scientific explanation" exists (mostly for the secular people), the danger of denial of something obvious (as the example of two stars) also exists. I am not afraid of an Astronomical event connected to the Great Warning, it will certainly Not shake my faith in God the Creator of everything, including of all stars etc. It is a pity there aren't more sermons on that. So many angels are painted together with stars in the churches.