No guarantees on spelling, I heard this mentioned in a video game, when you are attempting to snipe someone from a very far distance with a .50 cal sniper.

I would like to know what it is, if it even exists.

If you shoot towards north, Coriolis force makes the bullet bend towards East (and towards west if you shoot towards south), if you are in the northern emisphere, the opposite in the southern emisphere. The formula is:

**F**_{c} = -2m

**ω** X

**V**_{r}**F**_{c} = Coriolis force

m = bullet's mass

**ω** = Eart's angular velocity (of spin)

X = vectorial product

**V**_{r} = bullet's velocity

At

**45°** latitude, considering a total bullet's straight trajectory of

**8 km**, travelling at an average speed of

**800 m/s** (just invented data, not sure how that distance and average speed could be realistic for such distance) then the total bullet's shift towards east is about

**4m**.

If the average speed is proportionally smaller or greater, the shift will be

*inversely *proportional smaller or greater, that is the shift is doubled if the speed is halved (with the same distance travelled); if the total distance travelled is proportionally smaller or greater, then the shift will be

*square* proportionally smaller or greater (with the same average speed); for example for half distance the shift will be (1/2)

^{2} = 1/4 --> 1m; for 3 times the distance the shift will be (3)

^{2} = 9 --> 36m; the effect becomes more and more significant for long distances.

You can enjoy evaluating the shift with different values of speeds and distances.

This computation is very approximate because the trajectory can't be straight at all in this case (and I'm not referring to Earth's curvature only, but mainly on bullet's parabola).

Note that it's not a real force but an "apparent" force, as centrifugal force, due to the fact Earth is a non-inertial frame of reference. Another effect of that force is the more consumption of the right rails for trains travelling towards North (in the northern emisphere, ecc.)