From the ME3 codex on Reaper Capabilities:
The Reapers' thrusters and FTL drives appear to propel them at more than twice the speed of Citadel ships. Estimates of their location in dark space suggest they can travel nearly 30 light-years in a 24-hour period.
There, in the most up-to-date source on FTL travel it states that maximum FTL speeds are less than 15 ly per day. Therefore even without stopping to discharge the drive core or pick up fuel and supplies it would take 19.5 to 23.5 years to cross the galaxy. For reference, it would only take about 2.5 years to travel around the earth at 20 miles per day and the earth was very isolated until only a few centuries ago.
Also of interest from the ME3 codex:The amount of eezo and power required for a drive increases exponentially to the mass being moved and the degree it is being lightened. Very massive ships or very high speeds are prohibitively expensive.
So while it seems higher speeds than ~14 ly/day are possible they quickly become prohibitively expensive. It also raises the question of whether large-scale intergalactic FTL travel is even feasible for any period of time. Eezo is stated to only form in the remnants of supernovae and is extremely rare otherwise. It is possible that more eezo would be consumed shipping it from mining facilities than would actually be mined depending on how far they are from settled planets.
This could also explain why the Normandy uses up fuel so quickly between stars. It's probably traveling much faster than normal which would exponentially increase its fuel consumption.
Modifié par Arcturus Shepard, 15 mars 2012 - 05:18 .