Sure depending how you measure- the slowest man made objects are travelling at >500k MPH, relative to the galactic core..
in practice it comes down to acceleration and deceleration, with no real theoretical limit other than light for the maximum speed reached, though there are some interesting possible work-arounds there also.
There seems to be a fair consensus around 10% light speed for the time being, though you could always contact NASA and tell them where their calculations are wrong
Geoffrey A. Landis of NASA's
Glenn Research Center states that a laser-powered interstellar sail ship could possibly be launched within 50 years, using new methods of space travel. "I think that ultimately we're going to do it, it's just a question of when and who," Landis said in an interview. Rockets are too slow to send humans on interstellar missions. Instead, he envisions interstellar craft with extensive sails, propelled by laser light to about
one-tenth the speed of light.
Mission Laser Power Vehicle Mass Acceleration Sail Diameter Maximum Velocity (% of the speed of light)
1. Flyby – Alpha Centauri, 40 years
outbound stage 65 GW 1 t 0.036 g 3.6 km 11% @ 0.17 ly
2. Rendezvous – Alpha Centauri, 41 years
outbound stage 7,200 GW 785 t 0.005 g 100 km 21% @ 4.29 ly[
dubious – discuss]
deceleration stage 26,000 GW 71 t 0.2 g 30 km 21% @ 4.29 ly
3. Manned – Epsilon Eridani, 51 years (including 5 years exploring star system)
outbound stage 75,000,000 GW 78,500 t 0.3 g 1000 km 50% @ 0.4 ly
deceleration stage 21,500,000 GW 7,850 t 0.3 g 320 km 50% @ 10.4 ly
return stage 710,000 GW 785 t 0.3 g 100 km 50% @ 10.4 ly
deceleration stage 60,000 GW 785 t 0.3 g 100 km 50% @ 0.4 ly
But again, we are discussing all this
<60 years since the very first manned space flight.... in a galaxy
billions of years old- if ETs exist, we have to assume at least some of them would have had a little more time to work on all this by now!!
i.e. The point is why none of them ever reached us given billions of years to do so, not why we haven't reached them in 60...