Oh, thanks, I totally forgot about the Slashdot bitchslap.
And I'm not claiming the tr0lls weren't clever and occasionally hysterical. I'm just saying that the continual repost of "BSD is dying, Netcraft confirms it" on every single story had long degenerated from trolling to nothing more than protoplasmic copypasta spam, right down there in the sewage with the casino links. (And yes, there were many funny on-topic variants of the BSD meme that brightened up lots of different comment threads.)
I don't need to stand by the rotation theory. However, the 2.5 degrees that the Earth rotates are about equivalent to the downrange distance.
The first stage is going about 1/5 of the target LEO orbital velocity at separation. While you might well model the trajectory as a parabola over flat ground, given the lack of fuel I would expect that SpaceX puts a lot more care into their trajectory. So far I've failed to attract the attention of the person responsible for Flight Club, the most trusted modeling of SpaceX flights, but I'll message him directly.
Well, Alastair, you should probably not get snotty and ad-hominem, unless you want me to comment on how a one-time sci-fi author and the Unix guy at Dish doesn't really have more authority than the random person one might find in the SpaceX group on Reddit.
It happens there are a few people over there who are rocketry professionals, have the math, and have followed SpaceX long enough. So, sure, their opinion can indeed be trusted.
So far, we have a suggestion from one of the lesser folks there that raising the apogee takes advantage of the Earth's rotation. We'll see if we get the attention of the right people.
Here's an illustration of the boost-back to RTLS trajectory. You can see that it very definitely goes up. And to prove from observation, you can actually see where the two trajectories separate in photos from yesterday's launch. It's a rather dim curl up, and another continuing East, in Jason Ruck's photo and John Kraus's photo.
At the speed of stage separation, they rocket isn't going fast enough to stay in orbit, but it is definitely in the regime where orbital mechanics has a macroscopic effect. If you think about it, this is going to be the case at some reasonable fraction of orbital velocity.
This is just like the way people whined that color film had ruined the medium, and the ones before them who whined about talkies and yearned for the days of silent films.
I started at the NYIT Computer Graphics Laboratory in 1981 and left Pixar in 2000. These days I produce or am on screen once in a while.
While I was at NYIT they weren't story oriented, and thus all you see of them is demos. Pixar, on the other hand, always put story first. We knew that we could not make a film stand up on effects alone.
Today, a good 3D animation house can make absolutely any scene they like. And thus there isn't anything special about doing so. It's there if it needs to be there to tell the story, and not otherwise.
To return to landing site it goes UP, back, and down. Orbital mechanics.
East takes you out, out takes you west, west takes you in, in takes you east, port and starboard bring you home.
[Apologies for the l33t sp33k, but the lameness filter is actually pretty effective at blocking even the discussion of the older common tr0lls.]
Tr0lling originally started out as posting something on-topic but factually wrong in order to get reactions from people. Tr0lling was elevated by some to become its own art form; the best tr0lls could get pedants to crawl out of the woodwork like termites fleeing a flood. And the resulting posts and reactions were genuinely funny -- anyone who understood what was going on got a good laugh. But that kind of tr0lling peaked over a decade ago.
Other garbage has since cycled through Slashdot like ugly fashions on a New York runway. First came the memes: sites confirming the passing of various operating systems, etc., which at least often tried to stay on topic. They were inoffensive, but showed little real effort; they quickly stopped being amusing. Then came the nonsensical randomness, such as a certain movie starlet known for Star Wars and a lap full of hot breakfast food (I never quite understood that one). They were perhaps attempting to be absurd but mostly came off as stupid; again, they were reasonably inoffensive. But the current rash of copy-paste has become the new nadir, where cud-chewing morons too stupid to create their own original racism have figured out enough of the clipboard to re-vomit someone else's puke in the comments.
( In a huge burst of irony, some of the tr0lls themselves got pedantic, claiming the garbage posts did not qualify as "tr0lling" under their definition. Thus ended the reign of the major tr0lls, whose posts were quickly modded down into the -1 muck along with the rest of the bile. )
Throughout all of this, anonymous cowards and other low-lifes have always posted hate speech, political screeds, and offensive, racist crap. Browsing at -1, however briefly, will expose you to the words of horrible, useless human beings. Don't do it -- just click "no".
Slashdot has fought back, of course. The lameness filter has long kept out garbage like ASCII art, and certain phrases that I couldn't quote in this post. The remarkable bottom line is that Slashdot's moderation system, flawed as it may be, has kept the comments mostly readable for a very long time. Sites that failed to emulate it have come and gone, mostly forgotten by all but the Wayback Machine. Sites that still allow comments have almost nothing usable in them (youtube is a prime example of a site with unusable comments.) Meanwhile, Slashdot's community has managed to keep some semblance of order together. That's quite an achievement, especially over the nearly two decades of its existence.
The earth is like a tiny grain of sand, only much, much heavier.