Bad Astronomy: Misconceptions and Misuses Revealed, from ...

24 BAD ASTRONOMY BEGINS AT HOME
After a solid hour of driving, that amounts to a deflection of only
10 meters (33 feet). You couldn’t possibly notice this.
Still, it is there. It’s subtle, but over long distances and large
amounts of time it adds up. That can be a mighty sum, given the
correct circumstances.
And those circumstances do arise. An area of low pressure in
the atmosphere is like a vacuum cleaner, drawing in the surrounding
air. Let’s take the simplified view that we are in the northern
hemisphere, and assume that the air is coming in only from due
north and due south. The air coming in from the south is moving
faster to the east than the air near the center of the low-pressure
system, so it bends to the east. Air moving from the north is moving
slower than the air in the center of the system, and deflects
west. These two deflections add up to a counterclockwise rotation
to the low-pressure system. This is called a cyclonic system.
The opposite is true in the southern hemisphere. A low-pressure
system will spin clockwise because air drawn in from the north will
be moving faster to the east, and air coming in from the south will
be moving slower. The spin is opposite from the northern hemisphere,
and is called an anticyclonic system.
If the system is stable for a long time, days or weeks, it can
grow massively in strength. Warm ocean water feeds the system,
making it stronger. As the air gets closer to the center it moves
faster, like an ice skater who spins faster when she draws in her
arms. If the winds can gain in strength and blow at a hundred or
more kilometers per hour, it becomes a hurricane (or a typhoon if
it’s in the Pacific ocean).
All that, from that tiny deflection you can’t even feel in a car!
Does this sound familiar? Sure! It’s the same idea that Peter
McLeary uses to explain why water swirls the way it does when he
gives his demonstration in Kenya.
But there’s a problem: as we already saw, the Coriolis effect
only produces a measurable effect over huge distances and long
periods of time. Even the most decadent of bathtubs is thousands
of times too small and drains way too quickly to ever be affected
by it. It can be shown mathematically that random motions in
your water are thousands of times stronger than the Coriolis effect,