The Earth is one complicated place, and one of its many complexities is the Coriolis effect. National Geographic defines this effect as “the invisible force that appears to deflect wind” and influence the movement of “rotating objects.”Basically, because of the Earth’s rotation, the paths of objects moving in the air aren’t perfectly straight.
The Coriolis effect isn’t actually a physical force, but rather “just the ground moving at a different speed than an object in the air,” as National Geographic goes on to explain. With the Earth rotating as the object flies above it, it appears to move in relation to the ground.
Coriolis Effect Video
Coriolis Effect: The Science of Straight Shooting
How the Coriolis effect would influence a bullet traveling from the North Pole.
Coriolis Effect Sniper Shots
For example, the Coriolis effect influences the path of bullets. Snipers, whether in the military or hunting, have to consider it when firing their rifle long distances. When it comes to one hundred yards, there is not much affecting the bullet. However, if the shooter were one thousand yards from the target, the Coriolis effect (among other factors) would influence where the bullet lands.
Let’s say the person stood at the North Pole and shot their rifle. The bullet would lean toward the right from the shooter’s perspective. The opposite would occur at the South Pole: the bullet would lean toward the left.
Consequently, someone shooting at a distant target in the Northern Hemisphere may want to aim slightly to the left, and someone shooting at a distant target in the Southern Hemisphere may want to aim slightly to the right. Of course, factors such as the wind come into play as well.
Aiming Aircrafts and Satellites with the Coriolis Effect
The practical implications of the Coriolis effect are particularly clear when examining satellites. Just last December, a space transport company called SpaceX revealed that it wants to make a precise landing on an ocean platform. An article on its official website explains that the project only has a 50 percent chance of succeeding due to how difficult it is to factor in all the variables involved.
As you can assume, the Coriolis effect is one of those variables. It plays a major part in aircraft and spacecraft launching or landing. If an object is launched in the Northern Hemisphere, it will deviate to the west and if launched in the Southern Hemisphere, to the east. As SpaceFlight.esa.int explains, this is in part because the object is lagging behind Earth’s rotation after it leaves the ground—just like a bullet leaving a rifle. And, of course, in the case of a landing, the Earth’s rotation and gravitational pull have to be taken into account.
Whether or not SpaceX is successful in its landing, the data gathered will be very helpful in the future. The company announced that it has a dozen launches planned for the next year.
These are just a few things involved with the Coriolis effect. Even airplanes are affected and need to take it into account, or they will end up in another city entirely as the Earth rotates beneath them. But even if you’re not a pilot or a scientist, you can at least bring up the Coriolis effect in conversation and sound smart.