our galaxy has around 300 billion stars and atleast around 180 billion star systems (most star systems have 2 suns), now the Milky Way is one of the larger galaxies in the observable space, so let's say an average galaxy has around 100 billion star systems

based on that number, how many of the games you suggested are anywhere near big enough to be called "open galaxy" ?

No Man's Sky reportedly has 2^64 planets and if we assume an average of 10 planets per star system (average should be waaay lower though, as by today's knowledge planets are expected to be extremely rare in binary star systems) that means there's about 1,800,000,000 billion(1.8 x 10^18) star systems in that game, extremely much bigger than our own galaxy and worthy of the title "open galaxy"

I have the feeling that No man´s Sky is going to be boring, all the videos i´ve seen (a lot) show just a contemplative game, something like an experience more than a game. it doesn´t matter how huge the game is if it´s empty and you have almost nothing to do.

They insist on all the things you will be able to do, and how amazing is the multiplayer. But all they are showing is just contemplative aesthetical pleasure. 

People are taking this as a mainstream game when is probably a very niche experience.

It's not really a 'game' in the traditional sense, but Space Engine is essentially an open universe and has been in development for about 10 years :p Here's a pic to give you an idea of how big it is:



The first pic shows a laughably tiny number of the galaxies in SE, and every one of them is filled with millions of stars, planets and moons that you can travel to. Makes you feel pretty small '-'

A video showing some of the cool places people have found: https://www.youtube.com/watch?v=b1O3XCsGnC8

Anyone else feel like their reading about the new game called Fable or Spore, when you hear people talk about No Man's Sky.

Lets be honest here, No Man's Sky is too big. Using procedual generation and the vast size of the galaxy there's no doubt that there's places that look almost identical, whether you visit two places that look the same or not is another matter entirely but it's over inflated numbers aren't necessarily impressive when they've been created with procedual generation. Other than they got the thing to run.

Elite Dangerous has 300 billion star systems that's enough.

Eve Online has over 5000 star systems which is more than enough aswell.

You get to a certain point where size becomes irrelevent because it's so big no one will ever visit the vast majority of it. I doubt I will ever vist more than 1800 systems in No Man's Sky (0.0001% of it's galaxy.)

Minecraft worlds on a pc have a size limit of 4,722,366,482,869,645 km2 that's 9,258,235 the size of the earth. Is that really so impressive? Making a vast world through procedual generation is very easy, let's just hope that No Man's Sky manages to fill it with something meaningful.

Ah, where is the good old Electronic Arts gone? These days there is a completely different company named EA, that shits all over the legacy.

It will be an honor buying no man's sky. People should support projects like this.