this post was submitted on 09 Mar 2025
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[–] [email protected] 11 points 1 week ago (4 children)

really interesting. what's the reason why?

[–] [email protected] 7 points 1 week ago

If you've ever heard of sailors talking about 'the doldrums' the calm bit is the doldrums.

[–] [email protected] 2 points 1 week ago

I'm going to say the Coriolis effect but... I don't know?

[–] [email protected] 81 points 1 week ago (1 children)

Stole explanation from r/ELI5:

When you stand on the north pole how fast are you moving relative to the earth’s core?

Zero, you just spin around in place once every 24 hours.

When you stand on the equator how fast are you moving?

1000mph, you have to circumnavigate the earth in a day.

This difference doesn’t matter much when you throw a baseball, but it absolutely matters when you’re a storm the size of a country. > This disparity in relative speed rotates the storm since the equatorial side is moving faster than the polar side, and it provides the swirling structure of the hurricane.

But here’s the problem - storms in the north spin counter-clockwise and storms in the south spin clockwise.

That means to cross the equator you have to stop and reverse direction. That’s not happening, and hurricanes never track near the equator because neither the storm itself nor the prevailing winds that push it around can approach this reversal boundary.

[–] [email protected] 36 points 1 week ago (1 children)

The equator itself is associated with very low wind speeds, aka the doldrums.

[–] [email protected] 9 points 1 week ago

Ah, the calm belt.

[–] [email protected] 14 points 1 week ago (2 children)

Probably Coriolis effect? I’m not a professional meteorologist but I am an amateur meteorologist. I live in New Orleans and hurricanes follow somewhat predictable patterns. (Maybe not always where you can pinpoint exactly where they’re going but they tend to turn north in the northern hemisphere and south in the southern hemisphere.)

[–] [email protected] -5 points 1 week ago* (last edited 1 week ago) (1 children)

The coriolis effect is a fictitious force, it's just an artifact of not doing measurements in an inertial reference frame.

Edit: If I were to attribute it to anything, I'd attribute it to the actual rotation of the earth.

[–] [email protected] 2 points 1 week ago (1 children)

As the highs lows are part of the earth's atmosphere and thus trapped in a non-inertial frame of reference, they indeed experience the fictitious forces, such as the Coriolis and the centrifugal force.

[–] [email protected] -3 points 1 week ago (1 children)

The coriolis effect is not an actual force, that's all I'm saying.

[–] [email protected] 2 points 1 week ago

Which is why we call it the Coriolis effect rather than the Coriolis force

[–] [email protected] 6 points 1 week ago

You can also look at some of the coastlines and see the millions of years of erosion from the same patterns once the continents moved more into what we have now.