I see there are a few similar topics in this subforum so I guess this is the best place for this topic... Unless there's a dedicated exo/astrobiology subforum. Keeping it very simple: a) we are sentient multicellular organism on a random planet in a random galaxy. True or false... b) we are the only ones everywhere. True or false... If a and b are true then we are the rarest thing in the universe. If a is true and b false then we contemplate c) c) a vehicle coasting at considerable fractions of c ( v/c ), then according to relativity the t' (traveler time increment) to t (observed time increment) is: v/c ---- t'/t 0.0 ---- 1 0.866 ---- 0.5 0.900 ---- 0.436 0.990 ---- 0.141 0.999 ---- 0.0447 0.9999 ---- 0.01414 0.99999 ---- 0.00447 0.999999 ---- 0.00141 1 ---- 0 Ignoring 1c and 0, the last line of the table for obvious energy requirements, if vehicle is traveling at 0.866c it will traverse 1 light year in 0.5 years... aka vehicle appears to travel for 1 real earth clock year, but inside occupant clock only measures 0.5 year of elapsed time, 6 months. If it's 0.999999 then 1 light year will effectively last 0.00141 years or 12.5 hours onboard, while the destination wait 1 actual year for vehicle to arrive. If these calculations are correct then I don't see why distances are a problem for interstellar travel as long as the traveler has no intention of ever returning home to find every loved one has aged... If exploration is the ultimate objective then then onboard time is obviously insignificant. edit: I've inserted some lines in that "table" cause I'm not sure how it looks in desktop, on my Android it doesn't allow desktop mode for the forum.