Cornwallis said:

A good orbital bombardment would shut those hairless apes up pretty quick, I think. Who's going to argue with someone who can kill a billion people in an afternoon? Hell, I'd macrocannon New York, London, and Tokyo just to show I mean business before even talking to anyone. I get the impression from WH 40k that fusion reactors are tiny suns encased in metal; the stresses incurred in such a device and its peripherals could easily withstand any terrestrial nuclear detonations, yet alone armor. Maybe there are weapons in secret development that could do more than scratch paint on a void ship?

I think you also overestimate how many of "we" actually understand the technology we use every day. Most Americans, for instance, probably couldn't explain how a internal combustion engine works other than saying something like,  "I put gas in the tank here and it goes to the engine and explodes and that turns some gears or something and moves the tires . . ."

Warmaster Picklehauber said:

Here I strongly agree. Many people don't even know how to send an email if they don't do it step-by-step beginning by opening web browser. Almost like it is a 'send an email ritual' which cannot be interrupted in any place or it has to be repeated from scratch. Any likeness to AdMech?

ShadowRay said:

Yep. I have helped put together a couple of desktop computers, from components, and this still hasn't helped me understand how they work at all. I certainly couldn't build one from scratch, even with access to a Lathe World manufactorum. I just don't have the knowledge. Also, I'm sure not a lot of people can explain how the internet works either; other than a facile comparison it to the telephone (how do those work?) or something like that.

Certainly, in the Western World we use all sorts of technology in which we are only passingly familiar with even the basic elements, but don't fully understand at all. The only people I know who can really explain this sort of stuff are engineers and they aren't exactly a majority of the American population. Furthermore, they receive far more education than most. A lot of this information is freely available too; via internet or at a library. People are hardly going in droves to the local branch to find out how a internal combustion engine works, how to build a processing chip or even how to wire a house for electricity. I would say that even with all this freedom people are not concerned with how things work and merely that they do. Now couple that with a culture where it is considered unneccessary for all but a tiny minority (those with the opportunity to receive engineering-based college degree) to know this information and most of us only have a rudimentary understanding of what they are able to do. That's a pretty technologically ignorant culture. For some I know, saying computers are just magic or active "machine spirits" would hardly be  a step down from their level of understanding.

I've been thinking a lot about this lately because I am converting the sidewalk in front of my home to a brick pathway. Undertaking this project has made me realize just how ignorant I am of civil engineering and similar technology. Brick roads have been around for over 2000 years.

Given that the Emperor has been around since prehistory, it's very likely that the incursion would warrent his direct intervention and at that point you'd basically end up doing whatever he told you or get pulped. 

But hey, he had to get the Void Dragon to Mars somehow. Who's up for fighting a C'tan?

Warmaster Picklehauber said:

Actually from the description of 'Atomics' under ship upgrades, i'd wager that 20th century Earth 'nukes' are comparable to Poor or Common Craftsmanship Atomics. Good or Best being the realms of superior Martian engineering.

The shielding and plating on the inside of a reactor is superior to that of the hull most starships in 40k, but then space is a vacum with 0 Atmospheres of pressure and on average a temperature of outer space is -270 degrees celsius (metric, as the RP uses metric and faranheit is a stupid system anyway!).  
Of course that is entirely neutral conditions. Getting some solar radiation from a star? Well most of it will be absorbed by the ships shielding, or else everyone on board would be killed.

Now plasma fusion reactors are a thing of fiction currently (the science is solid but the practicality has yet to be found) but fusion takes place at roughly 10⁹ K (or 1 billion degrees celsius). You can take this to mean that internal reactor shielding is far superior to ship shielding, but on a far smaller scale. 

Plynkes said:

Nazis? In 1980? Sorry?

BTW, in their essence, most of humanity in the 41st millenium is essentially composed of Nazis (with respect to their mind set, albeit on a larger scale), and the Space Marines are among the worst of them, really.

Aajz_Solari said:

Entirely depends on the Astartes in question. Some chapters are ridiculously militant (Black Templars, Dark Angels etc) whilst others are rather more gregarious when it comes to their interactions with the Imperium and regular humans (Salamanders, Ultramarines and even Space Wolves to some degree). I'd say the attitude of the Astartes ranges from militant fascism through to limited socialism and brotherhood.