The Green Moon! So many questions!
1 - Wow, what are the odds that an astronomical event which lasts 90 minutes and happens only once every 420 years would fall directly on 4/20? I'm no mathemetician, but it has to be somewhere around the magnitude of "you gotta be fucking kidding me."
2 - I'm a little bit disappointed that it doesn't last for 80 (4x20) minutes. Come on, solar system, get your shit together.
3 - OK, obviously this is a semi-sophisticated bit of trolling, but is it being perpetrated by stoners? That would explain the green/420 references but man, isn't the whole point of being a stoner that you purposefully have other habits to occupy your time besides intesive-focus activities like photoshopping elaborate satirical memes? So, is it a non-stoner simultaneously trolling stoners and scientifically illiterate people who uncritically like and share dumb pseudo-science memes? Or a non-stoner who kind of weirdly wishes they could be a stoner, knows the shibboleths and thinks incorporating them is extra-hilarious?
4 - And perhaps the most important question of all: I saw this meme on Facebook because friends of mine were liking and sharing it. Are those friends in on the joke, and sharing it ironically? They must be, right? Right?