If you’re shooting past, say, 1,000 yards, you should be aware of how the rotation of the earth affects your bullet’s trajectory. This is called the Coriolis Effect and I tried my darndest in the video above to explain how it works and how to avoid missing that long shot.
TL:DR version:
- If you’re on the equator, you’re moving East at about 1,040 MPH while the Earth completes a full rotation in 24 hours. As you get farther from the equator and closer toward the North or South Pole, you slow down (smaller and smaller diameter circle, still 24 hours to go around it)
- If you’re shooting North or South, either you or your target is moving faster (if you’re in the Northern Hemisphere shooting South, your target is moving faster than you are).
- The difference in speed between you and your target causes point of impact drift.
- If you’re shooting East or West, your target is rotating around the curvature of the Earth (so are you, but once your bullet’s in the air it’s no longer connected to the Earth) and you miss high or low because of it.
- How do you know if your compass heading will make you miss left, right, up, or down? Watch the video above and find out!
And the thing you think is stationary, is also in motion, in several axis at the same time, like the orbit around the sun, the orbit of our solar system in the milky way galaxy, and maybe others.
Your actual track through the universe is a cork-screw spiral motion…
“If you’re shooting East or West, your target is rotating around the curvature of the Earth (so are you, but once your bullet’s in the air it’s no longer connected to the Earth) and you miss high or low because of it.”
Hmmm no.
This is the Eötvös effect not the Coriolis effect:
The Eötvös effect (yes its a real thing) is related to the Coriolis effect and sometimes they get jumbled together in explaining this but they are not the same. You are mixing the two here.
The Eötvös effect involves the change in perceived gravitational force due to the motion of an object traveling with or against the Earth’s rotation. It affects the vertical deflection of a bullet’s trajectory, especially when firing east or west. When shooting east, the bullet tends to (miss or) hit higher than aimed, while shooting west causes it to (miss or) hit lower than aimed.
“If you’re shooting North or South, either you or your target is moving faster (if you’re in the Northern Hemisphere shooting South, your target is moving faster than you are).”
Hmmm, no, not exactly.
relativity is actually a thing in science.
Relative to your speed the target might be faster than you, but it has nothing to do with “you’re in the Northern Hemisphere shooting South”.
For example; 10 MPH is still 10 MPH no matter where you are on earth.
You are confusing the earths speed with the target speed. If the target is standing still the target is moving at the speed of the earth at the point where the target is standing still, but if the target is moving then the target is still moving at what ever speed its moving no matter the point on the earth the target is at. If at the poles. the Earths speed is 0 MPH but the target speed is still what ever speed the target is traveling.
In other words, the target speed is relative to your speed and not the direction from you north or south.