Here you can see how India (to the left) is much greener than Tibet (right).
You can tell where the mountains stop the water from the wind
In India, this happens across hundreds of kms
And what causes the mountains? The Indo-Australian Tectonic Plate hitting the Eurasian Plate
But why is the Ganges valley so flat when it's just next to the Himalayas, the tallest mountain range in the world?
It's *because* of the Himalayas: They're so heavy that gravity crushes down the region around it! The same thing happens in the Indus valley nearby
Now we know why:
• It's flat
• Humid winds discharge their water there
But hold on, why are there humid winds to begin with?
They're not supposed to be there! Every other part of the world at the same latitude is a desert!
Why is the Sahara a desert but India a garden?
The equator is the warmest part of the world, hit directly by the Sun
Hot air, full of humidity, goes up, hits colder air, water condensates, and rains down.
But air keeps going, and falls down farther north, completely dry. Hence the Sahara.
So why not India?
The monsoon
In Indian summers, winds come from the sea, full of water.
What force pushing the monsoon is so huge that it predominates over the normal circulation of wind on Earth?
The sheer size of the Eurasian Plate being north of the only southern ocean on Earth
In summer, the air above the Indian ocean gets hot and fills with water.
But lands warms up faster than water
Eurasia gets much hotter
Air goes up above it
It creates a vacuum
And the hot, humid water from the Indian ocean invades India
And rains down at the Himalayas
This brings water across all of India, not just the Himalayas, making all of it fertile—even if the Ganges river basin is the most fertile.
In summary, in India:
Fertile soil ➡️ Population
Why?
• Hot (tropical)
• Lots of rain
➡️Rivers➡️irrigation & fertilizer
But ALL these conditions exist thanks to an ancient accident: The Indo-Australian Plate hitting the Eurasian one!
1. In summer, the Eurasian plate heats up north of the Indo-Australian plate (Indian ocean)➡️monsoon 2. These plates hit and create the Himalayas➡️stop the waters and rain it down to the Ganges valley 3. The weight of the Himalayas flattens the Ganges basin➡️best for crops
I hope you enjoyed this thread. If you did, follow for more. I write one of these every week or so.
The West Coast has many more Spanish names (like California, Oregon, SF, or LA) than the East Coast. Why?
Because of China and the rotation of the Earth:
You'll say: "It's because Spain colonized the West Coast of the US, but not the East Coast".
Sure but why?
The Spaniards visited the San Diego Bay 80 years BEFORE the Mayflower landed in the East Coast!
They didn't colonize the US East Coast because *they didn't care*
Why?
The Spanish wanted America for its $$
1st, they carried the silver from Mexican and Bolivian mines back to Spain. Then, plantation crops. On their way, they tried to convert as many souls to Catholicism
Anybody aiming at colonizing Mars should realize that the Earth's oceans are
• Easier to reach
• Easier to colonize
• More fertile
Oh, and there's nearly 3x land in the Earth's oceans (140M sqm) than in all of Mars (56M sqm)
The end goal might be to survive an earth 🌍 catastrophe but:
• It’s been around for a long time. Delaying this a bit is not risky
• Many 21st century techs will be crucial to colonize Mars: mainly fusion and AI for automation
• We still have much to learn re living in Mars
• The one likely catastrophe of the 21st century is an AI takeover, which Mars habitation wouldn’t save us from
So postponing Mars colonization for a few decades has no cost but the huge benefit of learning more
The Q becomes: how do you learn fastest how to survive in mars
The tiny island of Java has more population than all of Russia
More than all of Japan
Why?
More than the other 18,000 Indonesian islands together
151M ppl in an island smaller than Uruguay (3M)
Is it because of its strategic position?
No, the island of Sumatra and the Malay Peninsula to its north have always been better positioned around the Strait of Malacca
The size of empires is determined by transportation technology: The borders can't be beyond 1 month of travel from the capital
1. The Roman Empire
Left: Roman conquests over time
Right: The time it took to travel from Rome to different places
2. Egypt
• Deserts were impenetrable
• Not enough forests (wood) for a Mediterranean fleet
• Only the Nile could be traveled
• Nile travel was stopped by the 1st cataract
➡️the Egyptian kingdom was just the Nile between the Med and the 1st cataract
As kingdoms reduced the time to pass cataracts, they could expand a bit further.
Egypt eventually reached the 2nd cataract, while Kerma was between the 2nd and 4th