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How the planet under our feet works, from its iron core to the deepest ocean trench. Start with what the Earth is made of, then follow the moving plates: each note answers one question and links to the ones it leads to.
12 notes from Graphite. Free to read, with no account. Nothing here is for sale.
Start here
The note that answers the topic’s biggest question, then the two it leads to most directly.
Start here
The Earth is made of a thin rocky crust, a thick mantle of hot rock and a metal core of iron and nickel, liquid outside and solid at the center. How scientists know without digging there.
Graphite8 min read
Then
Plate tectonics is the theory that Earth's rigid outer shell is broken into plates that move a few centimeters a year, opening oceans, raising mountains and causing most earthquakes.
Graphite7 min read
And then
Earthquakes happen when rock on either side of a fault slips suddenly after stress from moving plates builds up for years. How the slip works, what magnitude means, and why no one can predict one.
Graphite8 min read
Every note
The three above, then the rest. Each answers one question and links to the notes it leads to.
Pangaea was the supercontinent that joined almost all of Earth's land from about 335 to 200 million years ago. How Wegener argued for it, why he was doubted, and what proved him right.
Graphite7 min read
Volcanoes form where rock deep underground partly melts and the magma rises to the surface: at subduction zones, at rifts and ridges, and over hotspots. Why some ooze lava and others explode.
Graphite7 min read
The Ring of Fire is a 40,000 km horseshoe of volcanoes and earthquake zones around the Pacific, where ocean plates sink beneath others. Why it exists, and its great quakes and eruptions.
Graphite7 min read
Mount Everest formed when India collided with Asia about 50 million years ago and crumpled ancient seafloor up into the Himalayas. Why its summit holds marine fossils, and whether it still grows.
Graphite7 min read
The Mariana Trench reaches about 10,900 to 10,935 m at the Challenger Deep, deeper than Everest is tall. Why depth figures differ, the crushing pressure, how it formed and who has been down.
Graphite7 min read
The ocean is salty because rivers carry dissolved minerals from rock into it and evaporation takes away only the water. Where the salt comes from, and why rivers stay fresh.
Graphite6 min read
The Amazon rainforest matters because it makes much of South America's rain, stores 150–200 billion tonnes of carbon and holds about one in ten known species.
Graphite7 min read
In AD 79 Mount Vesuvius buried the Roman town of Pompeii, first under falling pumice, then under hot, fast currents of ash and gas that killed those still there.
Graphite7 min read
The Bermuda Triangle is a loosely defined patch of the western Atlantic where ships and planes are said to vanish mysteriously. The records show no more losses there than anywhere this busy.
Graphite7 min read
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