Comment by moring

Didn't even think of this, but yes: 5km/h ~ 1m/s, which is 1/10^8 the real c. This multiplies the sun's Schwarzschild radius (normally ca. 3km according to Wikipedia) by 10^16, making it 310^13 km, with 1AU = 15010^6 km.

It's yet another xkcd-level apocalypse.