If you look at the Grimoire card for Jupiter, the great Red Spot is visible. This is expected to disappear by 2030. This means that Destiny does not in fact take place in the future.

Let the speculation begin.

I speculate that it is a different spot than the current Great Red Spot. This spot, "The Son of The Great Red Spot", was whipped into shape by Jupiter's extreme winds some six hundred years after the demise of it's father spot. This is supported by the idea that "human lifespans tripled" (how would you know unless you measured over ~200 to 300 years?) and that your Ghost mentions that The City took "centuries" to build when you first get to The Tower.

Therefore, Destiny is, in fact, in the future. :p

This is expected to disappear by 2030.

Wait, what?!

This is expected to disappear by 2030.

Source?

It was supposed to be "extraterrestrial anticyclonic storm lifespan tripled," but the actor thought it sounded silly and changed the words.

The Grimoire could easily have been constructed out of past data. The fact that it displays today's Red Spot could mean as little as that the Tower has access to images from today's astronomers.

Not to mention how it could have easily been an oversight on Bungie's part.

No astronomer I know of actually thinks this will happen, just that it is possible.

We've been watching this thing since Kepler pretty much uninterrupted. While it is a mystery to us exactly why it continues, new research and computer modeling indicates it has something to do with vertical winds and gases keeping the storm stable. Initially, scientists thought it continued to gain energy by sucking up smaller vortices. This doesn't explain its current longevity, but the vertical winds keep it running in mathematical models potentially indefinitely. Because of this, many astronomers saw no reason to buy into the 2030 thing from 2014 that you're talking about.

Considering we know not what mechanism exactly keeps it going, we cannot predict anything. The idea that it will be gone by 2030 is due to extrapolation of trends found in very recent years using a straight linear regression best fit line on the data. We haven't really had very good measurements of the red spot for more than 70 years, and in its cartoonishly long lifespan, that is nothing. Right now, it's shrunken from times in living memory of many of our forumgoers. I show students every week the red spot, or bright pink spot, as I call it, and it is pretty small, much smaller than photos from around Pioneer's time...but this doesn't necessarily mean anything. See photos. Guess which is which.

This may be a normal ebb and flow of the red spot, or it might actually be leaving. We don't really know, and all the astronomers, even the ones mentioned in the press releases touting this attention grabbing headline, say they don't really know, just that it's possible.