If the planets in the conjunction also happen to be in the same part of the sky where the Sun is -- as was the case with Jupiter and Saturn 400 years ago -- then nobody can see the conjunction (without special equipment anyway). This time, those two planets are about 30 degrees east of the Sun, so are still above the horizon after the Sun sets. So everyone gets to see them together on the evening of conjunction day (even if most places won't see them at the exact minute of closest approach).

Hey, reddit's good enough for President Obama...
http://www.reddit.com/r/IAmA/comments/z1c9z/i_am_barack_obama_president_of_the_united_states/

Are you sure that's a "focused shock wave"? It looks to me like the roof of the building flying upwards (while presumably shattering, so you don't see a large object falling back down again. I'd expect the roof to be lighter and less reinforced than the walls of the building, so more likely to be flung away by the force of the explosion. By the way, though this has been called a "hydrogen explosion", I'm not convinced that there was any combustion, since I don't see any flames. I think it was just a violent gas release (hydrogen, I guess?), as pressure inside built up too high.