I have a couple of questions around the Lore of Eve, which I haven’t been able to find the answers for.
Roughly how long has the eve gate been closed for, thousands of years? more, less?
Depending on the answer from the above question and how long the dark times were do New Eden people still even remember earth?
Thousands of years yes I am not sure exactly how many wether is 3-4000 or over 10000 years and yes they all but forgot about their origins.
Earth is basicly more like a myth to most people.There is also extremely few information to be gathered or artifacts of the old first civilisations that came from the milky way into new eden due to few factors:
Some of the old civilisations left very little tangible evidence behind them as they migrated or it got erroded with time or destroyed by rogue drones and scavengers.
Another aspect is the old Jovian Directorate deliberately cloaked artifacts and other ancient technology so they wouldnt fall into the hands of power hungry tyrants and lunatics
The collapse of the gate was a little under 15300 years ago. First contact between the Amarr and the other empires, excluding the Jove is only 175 years ago or so. https://community.eveonline.com/backstory/races/amarr/timeline/
Earth beyond the Gate is a legend that not everyone even believes in; even the idea that all people originated from one world is sometimes debated.
First contact between Amarr and Minmatar was about one thousand years ago.
First Amarrian star gate is 2000 years ago. Aside from the Minmatar the Amarr don’t expand that fast really. The Minmatar had only just started to expand when the Amarr jumped on them. Its bit of a stretch to really call them an Empire at that point.
Considering we have had “empires” on this single planet of ours, and by that time the Minmatar were a space-faring nation with habitation on several planetary bodies in three different systems, I beg to differ. 
Anyways, when people (OOC) talk about ‘the empires’ they generally mean the four nation-states of EVE, so I assumed your comment meant them, originally.
Technically, I agree that you could view Amarr/Minmatar as one “block”, of course, them having a much longer shared history than the others and being pretty much one nation (the Amarr Empire) with a number of slaves at that point. There’s probably still people in the State and Federation who think about it that way.
The state and federation claim to be free but in reality they are the same as the Amarr, slave states using the masses as cheap labour. Worse yet the federation claim democracy; but us intaki know different!
Can we not ic propaganda spin in an ooc thread please…
The Intergalactic Summit is thataway. This forum section is the place we go for discussing the lore; the IGS is (one of the places) for living it. 
You know, I wondered about this too. Like, could one make a reference to something “of the old world” without people being like “Huh? The eff are you even talking about?”
Not really, its a long forgotten myth.
As I recall, the Earth and even what the Eve Gate is forgotten - possibly subject to some religious nonsense by the Sisters, but basically the “gate” if that is what it is is a shattered giant something. With EVE written on it.
There’s a difference between what we know as players and what characters know. And a lot of the early history is still unknown and subject to exploration. So yes, forgotten not even myth.
There’s quite a lot of known unknown in the back stories. Even where stuff is “known” it may be specialist knowledge - for example could you be expected to know the details of the latest archeological discoveries of sites in, say, Central Asia? Personally I couldn’t give even an overview of the subject. But someone who has spent a lifetime studying it will know it.
Knowledge isn’t universal.
So make a reference to the “old world” and people won’t know what or where you are talking about. It’d be like talking about “the old 'ole” and meaning a cave in the Rift Valley. Except we’ve more evidence of that cave than a citizen of New Eden has of Earth.
The only concept is that we probably have a common ancestor since we are all human, but where that common ancestor was from, no one knows
There’s a lot in being a simple person from the backwaters…
We are part of an interstellar civilization. Our scientific community knows that the fossil record does not support the spontaneous appearance of humans on multiple worlds. Said scientific community has dated the spread of colonies, and it knows that the EVE Gate was the origin of our presence.
The “it’s all a legend” nonsense is fine for what specific individuals might think, but those individuals are the equivalent of “flat Earthers.”
Also worth noting, as an aside, that the name of the gate on the Milky Way side of the wormhole was ADAM, and was located in the system of Canopus.
Its all to do with time. Presumably the original settlers were 6,000 years or so more advanced than ourselves. Projecting from current technologies they probably didn’t even use writing that often. Talk to device, device records and marks for any future reference. From the collapse of the Eve Gate to people heading into space again is maybe 12,000 years or more. That realistically means that the people who settled New Eden spoke nothing like we do today, possibly even down to a radically different conceptual framework. They then have to invent writing, from scratch, in a number of different and isolated environments. Given the circumstances its virtually impossible for anything to survive that. There are currently huge problems interpreting the everyday writing of people a few hundred years ago, let alone over 18,000 years of splintered history.
The language is completely different and the word used for Earth is not literally “Earth.” Neither are the residents of EVE literally saying “station” or “star.” However, deliciously ironic-under-the-circumstances mitochondrial “eve-adam” does not depend on language.
With the technology at their disposal, EVE’s organic chemists, physicists, and evolutionary biologists know more about our genetic heritage than we do. They know planets have been terraformed, which organisms were introduced to what environment and when, yadda yadda yadda.
But “mold theory” and other fluff.
Yes, life will evolve to solve similar problems in similar ways. Like legs. It will not evolve identical sequences of protein blobs into a single genome several billion protein blobs long. Humans came from one planet. Fact. EVE’s scientific community has figured that out, and has even described that planet in great detail despite having never seen it.
The only thing that would save “Earth Denial” as a valid premise is a retcon that flatly states: there was no Earth and we’re actually playing Star Wars: The Knights of the very very very very very Old Republic.
Fun facts about languages and translators: https://community.eveonline.com/backstory/chronicles/language-translators/
It is very probably that with respect to whatever anything is called New Eden, the only thing for certain is that the Gallente have passed laws that require calling it two things.