Well if we look at this: {R_{\mu \nu }-{\tfrac {1}{2}}R\,g_{\mu \nu }+\Lambda g_{\mu \nu }={\frac {8\pi G}{c^{4}}}T_{\mu \nu }\,.} {T_{\mu \nu }^{\mathrm {(vac)} }=-{\frac {\Lambda c^{4}}{8\pi G}}g_{\mu \nu }\,.} {\rho _{\mathrm {vac} }={\frac {\Lambda c^{2}}{8\pi G}}} If the energy-momentum tensor Tμν is that of an electromagnetic field in free space, i.e. if the electromagnetic stress–energy tensor {T^{\alpha \beta }=\,-{\frac {1}{\mu _{0}}}\left({F^{\alpha }}^{\psi }{F_{\psi }}^{\beta }+{\tfrac {1}{4}}g^{\alpha \beta }F_{\psi \tau }F^{\psi \tau }\right)} -is used, then the Einstein field equations are called the Einstein–Maxwell equations (with cosmological constant Λ, taken to be zero in conventional relativity theory): Additionally, the covariant Maxwell equations are also applicable in free space: Fαβ;β=0 F[αβ;γ]=1/3(Fαβ;γ+Fβγ;α+Fγα;β)=1/3(Fαβ,γ+Fβγ,α+Fγ, β)=0 {{\begin{aligned}{F^{\alpha \beta }}_{;\beta }&=0\\F_{[\alpha \beta ;\gamma ]}&={\tfrac {1}{3}}\left(F_{\alpha \beta ;\gamma }+F_{\beta \gamma ;\alpha }+F_{\gamma \alpha ;\beta }\right)={\tfrac {1}{3}}\left(F_{\alpha \beta ,\gamma }+F_{\beta \gamma ,\alpha }+F_{\gamma \alpha ,\beta }\right)=0.\end{aligned}}} where the semicolon represents a covariant derivative, and the brackets denote anti-symmetrization. The first equation asserts that the 4-divergence of the two-form F is zero, and the second that its exterior derivative is zero. From the latter, it follows by the Poincaré lemma that in a coordinate chart it is possible to introduce an electromagnetic field potential Aα such that {{\begin{aligned}{F^{\alpha \beta }}_{;\beta }&=0\\F_{[\alpha \beta ;\gamma ]}&={\tfrac {1}{3}}\left(F_{\alpha \beta ;\gamma }+F_{\beta \gamma ;\alpha }+F_{\gamma \alpha ;\beta }\right)={\tfrac {1}{3}}\left(F_{\alpha \beta ,\gamma }+F_{\beta \gamma ,\alpha }+F_{\gamma \alpha ,\beta }\right)=0.\end{aligned}}} F αβ = A α ; β − A β ; α = A α , β − A β , α {F_{\alpha \beta }=A_{\alpha ;\beta }-A_{\beta ;\alpha }=A_{\alpha ,\beta }-A_{\beta ,\alpha }} in which the comma denotes a partial derivative. This is often taken as equivalent to the covariant Maxwell equation from which it is derived. However, there are global solutions of the equation which may lack a globally defined potential. First, the determinant of the metric in 4 dimensions can be written: det ( g ) = 1 24 ε α β γ δ ε κ λ μ ν g α κ g β λ g γ μ g δ ν {\displaystyle \det(g)={\tfrac {1}{24}}\varepsilon ^{\alpha \beta \gamma \delta }\varepsilon ^{\kappa \lambda \mu \nu }g_{\alpha \kappa }g_{\beta \lambda }g_{\gamma \mu }g_{\delta \nu }\,} using the Levi-Civita symbol; and the inverse of the metric in 4 dimensions can be written as: g α κ = 1 6 ε α β γ δ ε κ λ μ ν g β λ g γ μ g δ ν det ( g) . {\displaystyle g^{\alpha \kappa }={\frac {{\tfrac {1}{6}}\varepsilon ^{\alpha \beta \gamma \delta }\varepsilon ^{\kappa \lambda \mu \nu }g_{\beta \lambda }g_{\gamma \mu }g_{\delta \nu }}{\det(g)}}\,.} Substituting this definition of the inverse of the metric into the equations then multiplying both sides by det(g) until there are none left in the denominator results in polynomial equations in the metric tensor and its first and second derivatives. The action from which the equations are derived can also be written in polynomial form by suitable redefinitions of the fields. In differential geometry, the Einstein tensor (named after Albert Einstein; also known as the trace-reversed Ricci tensor) is used to express the curvature of a pseudo-Riemannian manifold. In general relativity, it occurs in the Einstein field equations for gravitation that describe spacetime curvature in a manner consistent with energy and momentum conservation. So, basically Space Magic.

let's get the obvious out of the way first: Video game logic: everything's okay as long as it facilitates the story. Don't think about it so hard. Now, that said let's see if we can make it make sense. First, numbers: The impression we had prior to D2 was that all of humanity (more or less) lived in that one City. D2 doesn't exactly dispute this, other than confirming that there are people living outside the City walls. If all of humanity is confined to one city, our numbers total.... what? New York City alone has a population of over 8 million people and the planet has a population of 7 billion. We know the Collapse pushed humanity to the brink of extinction. My guess is humanity probably totals no more than 5-10 million. With numbers that small, we're don't have the manpower to retake the system. Further, human lifespan might be shorter again after the collapse, without all the golden age tech to extend it. Second, resources: We're still scrounging for golden age tech, which means we're not back to that level of development yet. Have you ever seen a large Vanguard ship? I've not, just the small single-man jumpships. Seems to indicate we don't have the tech or resources to build ships any bigger. My guess is that we know how to fix golden age FTL drives, but we don't actually know how to build new ones. Which leads me to... Third, knowledge: There is a lot about the golden age that we still don't know. So much information and history was lost in the collapse. It's very similar to how the world regressed after the fall of Rome. It took Centuries to get back to that level of civilization. I think the city is surviving on a myriad of patched-up golden age equipment, along with maybe some reverse-engineered variants thereof. But every time Golden Age relics are brought up there's an almost reverential attitude about them. Like present-day people can't believe such marvels were once commonplace. Golden-age humanity created and controlled several warminds: City-age humanity cant even talk to one. We have the foundations for rebuilding our golden age, especially now that the traveler is awake again. But we likely dont have the time. The fallen have been united and they're still fighting us for resources in our own back yard. The Cabal have been dealt a huge blow with the death of Gaul, but Calus is still out there and could in theory assume control of the Empire again. Savathun's coming with her Taken (the fall expansion, likely), and the Pyramid ships are coming from outside the galaxy. We had something like 400 or 500 years of Golden Age to build up our tech, but lost it all when the Darkness came. We likely dont have that kind of time now, and we're worse off than before.

You gotta love Science (proper Science aka Physics). For instance, if the Sun was to disappear the Earth would continue in its circular orbit for 8 more minutes before flying off at a tangent because the gravitational information that the Sun is no longer there would only travel to us at the speed of light 👍

It’s actually pretty standard tech in destiny The nls (near light speed) drive we get really explains most of it [spoiler]for people who didn’t pay attention in d1 it’s what you get from killing the archon in mission 2[/spoiler] It bends reality do as to make the passage faster So if you take a price of paper and roll a marble across it then that is normal space with the marble being the radio waves Then fold the paper and the marble will get from one side to the other faster

A. It's The Future. B. Advanced Satilite Communication Technology C. Advanced Alien Technology From Slain Enemies and the Awoken. D. Use The Mcguffin With The Thing To Continue The Story.

Shh. Don’t tell the writers. They forgot about that little fact. [spoiler]just like they forgot about most of d1’s story. [/spoiler]

Don’t they communicate via ghost? Like your ghost is your walkie talkie or something?

Well yeah their all powered on light. Not light years not electromagnetic waves a (not real object giving unknown power) we don’t Bungie made this type of light. They can make it do whatever they want. That’s like saying your in a nightfall and you ya e to wait 8 (or however far away you are from earth) minutes to get to you if they didn’t hitch a ride with you. Technically your saying that in real life we should all have Void powers, Arc powers, and Solar powers. But we don’t. Cause the light from the sun doesn’t give us powers. It’s the light from the traveler All I’m trying to say is your talking about sunlight to reach earth. How about travelers light to reach earth? There 2 different type of light Traveler vs Sun

I'm happy to suspend my disbelief (because videogame) however I must say I've thought this too. Quite amazing that the warminds could do the same network across the solar system. I also thought it odd in D1 that, Golden Age notwithstanding, the Cosmodrome had very normal looking broken down cars in it. Shouldn't they have been hover cars or something? I mean, we have sparrows so... Anyone else ever find that weird?

[quote]gravity[/quote] I’m an Unreal Tournament player from back in the day. They had a mod that was low gravity. Made for a very interesting change in tactics. Could be amazingly fun in Destiny.