Earth beneath our feet

What Lies Beneath Our Feet?

So far, humanity has only managed to explore about 12 kilometres into the Earth’s crust, and even that took us 20 years! But science never rests. Researchers continue to investigate how seismic waves travel through the Earth, and how their speed and behaviour change as they pass through different densities within the Earth’s layers.

At the Earth's core lies a solid, dense sphere of metal about 1,220 kilometers in diameter, composed primarily of iron and nickel. It’s as hot as the surface of the sun.

Surrounding this is the outer core, also made up of iron and nickel, along with elements like uranium and thorium. This outer core is where Earth's magnetic field is generated.

Above this is the mantle, which starts about 30 kilometers below the Earth's surface. The mantle is composed mostly of iron, magnesium, and silicon. It contains precious gems like diamonds, as well as rock formations.

Some of the world’s most famous diamonds, like the renowned Cullinan Diamond, 

were formed deep within the mantle, about 360 to 750 kilometres below the surface.

Next, we have the Earth’s crust, which can be compared to the hard shell of a boiled egg. The crust varies in thickness from 5 to 70 kilometers. This part of the Earth is cool and fragile, and can be easily broken. The crust is divided into several pieces called tectonic plates, which move slowly—about 3 to 5 centimeters (1.2 to 2 inches) per year. These movements are responsible for earthquakes and volcanic eruptions.

The Composition of the Earth:

• Iron – 32.1%
• Oxygen – 30.1%
• Silicon – 15.1%
• Magnesium – 13.9%
• Sulfur – 2.9%
• Nickel – 1.8%
• Calcium – 1.5%
• Aluminum – 1.4%
• Other elements – 1.2%

The concept of the Earth’s rotation and its spherical shape was first proposed by Greek philosophers. Later, the great Muslim scholar Al-Biruni, during the Ottoman Caliphate, accurately measured the Earth’s circumference. He claimed that the Earth is not flat, but spherical, and revolves around the sun. Using only mathematics and algebra, Al-Biruni’s measurement was so precise that it differed from today’s scientific measurement by only 2%.

حوالہ جات؛ 

زمین ہمیشہ سے گول نہیں تھی، سائنس دانوں کا دعویٰ