Hi, this is David from Minute Earth,
and here’s something really strange.
When certain spots in Australia and Russia
have the same concentrations of a particular atom in the air,
we know that it will start to rain at a certain spot in India 52 days later.
That seems both random and absurd.
After all, Australia and Russia are both 8000 kilometers away from India.
And while the atom in question beryllium-7
appears to make it rain,
it doesn’t actually have that power.
In fact, it just seems to hang out in the air.
The connection doesn’t seem to make any sense.
But, hundreds of years ago,
no one knew what connected a full moon to a super high tide,
or what connected hat making to insanity.
These bewildering connections only made sense
once we figured out the invisible mechanisms responsible for them:
gravity and mercury poisoning.
And what ties beryllium-7 and the far-off rains together
is an invisible mechanism called a Hadley Cell.
Hadley Cells are giant cyclical air patterns
that form as hot air rises from the equator 15 kilometers straight up
and then splits and flows North and South toward the poles,
before cooling, colliding with air coming the other way,
falling back down to earth
and heading back towards the equator.
As Hadley Cells cycle,
they drive all sorts of large-scale moisture patterns around our planet,
including the Asian monsoon,
during which 70% of the Indian subcontinent’s annual rain falls.
And Hadley Cells also drive around random atoms called beryllium-7,
which may not do anything special,
but they form somewhere special, 15 kilometers above the earth,
as cosmic ray particles smash into nitrogen and oxygen atoms
to create the beryllium-7 atoms.
The beryllium then hitches a ride on the Hadley express to the earth’s surface.
As the sun moves over the course of the year,
the Hadley Cells move with it,
which means that during warmer months in the Northern hemisphere,
there’s usually a higher concentration of beryllium in the air over Dubna,
while during warmer months in the Southern hemisphere,
there’s usually a higher concentration of beryllium in the air over Melbourne.
But at a certain date, usually in April,
the Hadley Cells are lined up such that they deposit
equal concentrations of beryllium at the surface in both Dubna and Melbourne.
When that happens,
we know that almost exactly seven and a half weeks later,
they will drag the monsoon rains across India.
And sure, maybe this weird predictive power
seems like just a fun party trick.
But just like we were able to use our understanding of gravitational pull
to predict the rise and fall of the ocean,
and use our understanding of mercury toxicity
to make hats and lots of other stuff safer,
we can actually put our understanding of Hadley Cells to use, too.
By being able to use the knowledge of Hadley Cell movement
to precisely predict the onset of the rainy season,
farmers in the Indian subcontinent—
and there are a lot of farmers there,
can know precisely when they should plant their crops
to grow as much food as possible.
And by doing so,
they can feed almost a beryllium, I mean, billion people.
We’re able to measure beryllium-7 concentrations in the air around the world
thanks to the Comprehensive Nuclear Test Ban Treaty Organization, or CTBTO.
In order to monitor for illicit nuclear tests,
they’ve set up a series of sensors in locations around the world
that detect all sorts of radioactive atoms,
including naturally occurring ones like beryllium-7.
This work has been mandated by more than 180 nations,
and the data that is collected worldwide is available to researchers
who want to further expand our knowledge about our planet.
If you’re interested, please contact ctbto.org.
Thanks to CTBTO for sponsoring this video,
and for helping keep the world safe from nuclear weapons.
Also, congrats to our latest caption contest winner.
The next image is ready for awesome caption suggestions
from all levels of Patreons at Patreon.com/MinuteEarth.
Hi, this is David from Minute Earth,