Why in the prologue people are astonished by "floating rocks"? Why do they point it out?

Outstanding! Thank you.

Thank you. I was off-target. Now I'm back on. You're absolutely right.

My line of imagination comes from Star Trek. Seeing Kirk or Picard sit in their ultra-conservative EasyBoy and look at the IMAX-sized window in front.

The more I talk, the more ignorant I sound. Derp.

Thank you, though. At least I feel smarter now.

Why move the ship at all if sensors are scrambled? You might hit something... like a Scourge.

they were in it before the ships sensors were scrambled. ME ship sensor  sense less the then the range of a solar system. the scourge range is as far as the cluster. even being so unwieldy to hide Aya  form the kett for decades. It even make's planet fall from time to time. 

Look at the intro. The Hyperion hit the Scourge while moving near Habitat 7, not while in FTL transit, and at least for some time after the Hyperion came out of FTL and the pathfinder crew was being urgently awoken.

And I read it. that's an argument on details not world building. that's a lack of exploration issue not a world building issue. i agree the worlds themselves don't allow for any in depth detail exploration but that's not the only way to do that. that can be done by talking to characters. It true that Shepard in ME2 never sees the day to day life of npc in ME2 but that's true with ME1 as well.

That don't counter what I said. I did not say they were moving too fast to sense it. I said their sensor were too scramble to sense it and sensor ranges are less the range of a solar system which we should know from ME1 and have that concept hammer in out heads in ME3.

And that's explains Ryder....Now for alec.

Well that could just be due to the low oxygen composition. Did you read the first part? Anything below 16% causes people to faint. It may not happen right away either, as the build up of CO2 in the blood is generally what kills people. A defacto panic attack + lack of oxygen for ryder could explain why they pass out even with the helmet on. Alec not hyperventilating allowed him to stay consciousness longer. As someone else said nitrogen can displace oxygen especially at high levels. We have lots of nitrogen in out atmosphere, but we also have 21% oxygen. Humans need at least 18% oxygen to remain alive and preferably higher as we exhale some oxygen when we breathe.

Though to be honest I am thinking that they want the "passing out of ryder" to be more in reference to the SAM connection. It actually still makes biological sense why both would have passed out and why alec died. Build up of CO2 is deadly and doesn't take long if you are without oxygen. Here on earth we pass out and then out autonomous system begins breathing again immediately. This controls our intake of oxygen and allows us to regain consciousness with no ill effects, but alec wouldn't have had that. His autonomous system would begin his breathing, but it wouldn't have made a difference lack of oxygen = fast build of CO2 = dead. Same reason people die in fires quickly, the build up of CO2 is what kills them. 

Not saying that bioware knows science well, but they aren't far off base with this one. If anything the space traveling science is way more out there and iffy then this.

that's if they breath it in. A person holding their breath don't pass out as quickly. I'm you don't pass up whey you go under water for a min. That normally happen with gas exchange.

1. i did not say osmosis creates a vacuum. that was someone else who brought that up.
2. what I stated creates a partial vacuum. A vacuum is created when you bring an area close to a total vacuum aka a state of nothingness. In that state something is pulled to fill it. it's a temporary partial vacuum. Boyle's law can do that based on volume and presser. 

Remember, a total vacuum does not exist.(you can't get dark energy out of an area.) All statement of a vacuum are references to bringing a location closer to a total vacuum.

dude, the human eye does not see a system way. Hell we can't even see mars from earth with out instruments. Take some consents of proportion. The parts the scourge we can see from the ship is far away and miles long. We would not see it in detail from a distance.that why ship sensor are  used.  The scourge covers systems. We would be in it before we sensed it. In Me3 we are given an Idea  how far ships sensor go...

And that is with a ship more advance then the ships in MEA.

My point is that the scourge is so big that by the time we can sense it we are in it. Saying that we should see it from a distance misses the point that our eyes can't see farther then planet side with out help. We don't even see the scourge off the planet we are on in mea.