How many miles per second to cross the milky diameter way in one minute?

The distance across the Milky Way is about 100,000 light years.....thus......

You would need to travel at 100,000/60 = about 1667 light years per second to cross the Milky Way in one minute

And since a light year = about 5.9 x 10^12 miles.....then

1667 x 5.9 x 10^12  = 9,835,300,000,000,000   about 9.8 quadrillion miles per second  (US measure)

6968 miles per second

Yep just like he said

NASA hasn't created a rocket that travels that fast yet, so although that's kinda true it's impossible. So, the only way is by travelling at 6968 miles per second.