That it's a mish-mash of old and new tech? We're so far into the future, now, but we can see from the grimoire cards that the golden age gave us an instantaneous jump in tech, courtesy of the traveller. So it is possible that the golden age occurred right about now in real world timeline. You can see in Old Russia that the planes are just like we have now. You can see cellphone towers. Street lights and building lighting is identical to today's. Even some computer terminals are pretty dated. There are even husks of cars that we have now. BUT, these are also on venus...as are regular office blocks. So here's where I'll posit another theory. We are all in a Vex simulated environment. Yes, many grimoire cards already hint at an artificial simulation. But I think a more physically crafted environment is closer to the truth. The reason we can see this mash up of dated through to advanced tech is because the Vex don't know what is dated or advanced to us. They span millenia, possibly to the beginning of time. You could forgive them for not discerning the difference between the mere hundred years that separated us from horses and swords, to computers and guns. They want to simulate that 'humans' were on the moon, venus and earth, and so have generated what they perceive to be typical 'human stuff'. To us though it should be jarring. Why are 90s cars on venus? Why was our mass exodus from earth done in 50s military transport aircraft? Furthermore, grimoire cards tell us that golden age humans were on venus until the vex came along and kicked us out. But that's impossible. Not even considering the atmosphere for a second; the pressure on venus is enough to make it all but impossible to even move. We can also see that there is vegetation on venus now, and we can move there now. So it's clear that the vex have physically altered the planet's orbit. And grimoire cards tell us they have exactly this sort of power anyway. And we know they have moved mars too, as you can see it clearly from the moon as a red sphere. This is not currently possible. So the vex have moved things to their preference, but this must also mean that humans couldn't have ever existed on venus until after the vex intervening. Given we know that we haven't been there, historically, post vex, then all the evidence of us there is faked. Which also accounts for the 90s office blocks, roads and cars. So what's up? There are more unanswered questions. Like the 'human' skeleton with the huge elongated jaw sat at the array terminal on earth. Also the fact that we have failed to make ships that would get to jupiter, and likewise that xur has to be constructed of millions of dead cells to even exist in the tower. The 'are we dead' theory is a whole other story though. Wherever we are though, we know it takes immense and special effort to even reach us. Refere Xur (read the grimoire), and reference the Stranger. ******UPDATE FOR OCTOBER 2015, SINCE THIS THREAD REMAINS POPULAR****** And then take note: - we have a grimoire card specifically covering guardians witnessing a vex simulation where the vex are running hundreds of copies of those guardians through the same situation to see what variants occur. - the opening trailer shows the guys coming to mars, but then the scenery background changes a little, and it then does this multiple times in quick succession, as if this moment had happened a hundred different ways, sightly different each time. - the stranger appears out of nowhere to assist us, and disappears just as easily, most likely back to the real world outside of our simulation. - the stranger makes numerous references to things repeating, and also knows details of our missions before we've even done them ourselves. - what is the in game reason for why we can go back doing the same content over and over, or why thousands of guardians can kill crota etc? - the traveller's "light". Really just space magic? Or does the traveller act as rogue malware through the vex simulations, hacking the programme to generate weapons, ammo, resurrect us when we should be deleted. Growing itself an army of sentient consciousnesses to overrun the simulation? - ever wondered why you haven't seen a single human being, ever, who is just a regular citizen and not part of this whole combat scenario?