Our planets History Cast in stone' for a south african travel Magazine
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Answer:
Dinosaurs roamed Earth at the peak of their population. Small mammals were spread throughout the world. The ancestors of birds and reptiles had split from their common dinosaur ancestor. The continents in the northern hemisphere had almost entirely taken the same shape as today, while Gondwana was still splitting up.
Earth gets hit by hundreds of meteorites every year. These strikes are spread all over the planet’s surface. As they rocket towards Earth, and begin to pass through our atmosphere, the larger ones always break down into smaller chunks thanks to the intense friction and heat during entry – while the smaller ones crumble into minuscule particles or dust. And in this phase, they put on a show of light. There’s either a blazing fireball or a meteor shower. Meteor showers are mostly regular events because a comet or an asteroid in space travels in a specific orbit. As it moves further away from the Sun, ice builds up on its surface. And as it returns, getting closer to the Sun, heat from the star whips the ice and dust into a tail left trailing the object. This trailing material either moves slowly in the rock’s wake or simply gets suspended in space. And when Earth reaches this suspended dust, they fall towards the surface while we get showers.
Meteorites are not hard to find if we know where to look and how to identify them. While most of them end up in the ocean – because our planet is covered with so much water – several do touch down on land. As they burn up on their way down, they acquire a black coating that makes what would otherwise have been a distinctly alien-looking thing appear like any other rock on Earth. Most people don’t even spot them for what they are when they do. However, they do stand out against landscapes that are lighter in colour. This is why meteorites are easily spotted in Antarctica or the Sahara desert.
We have a large quantity of meteorites from the moon and Mars. These were pieces of rock that were floating about in space after collisions with the larger bodies billions of years ago. We can positively identify the source and age of a meteorite by looking at its composition, structure and its weathering. As it happens, the greatest source of meteorites on Earth is the asteroid Vesta, less than a fifth the size of the moon.
Zooming around the Sun between the orbits of Mars and Jupiter, Vesta was once hit by a very large object that left it with a gigantic crater, called Rheasilvia, nearly spanning half its body. This impact didn’t just create the most prolific source of meteorites on Earth, it also melted off a large portion of the surface. The molten liquid was sent sloshing up over the crater’s edges. And when it fell back downwards, it froze midway, forming the Solar System’s tallest mountain.
Most meteorites we talk about are small, tiny stones, ranging from the sizes of raisins to pebbles. Sometimes, however, meteorite hunters may find a larger rock; even more rarely, they may stumble upon something the size of a boulder, a truly unique find for larger rocks are likelier to have disintegrated in the atmosphere or upon impact. The biggest we know about is the nine-metre-wide, nearly rectangular Hoba meteorite in Namibia. It is flat on two sides, so it might’ve skipped in the atmosphere like stones skipping on water. In fact, it had slowed down so much that it is thought to have fallen with a giant thunk and made no crater on the ground.
Explanation:
After some long years of discoveries of geologists, the rock formations in the Barberton Mountain of South Africa were concluded to be 3.2 to 3.57 billion years old. The discovery was formally known as “the history of our planet cast in stone”.
The Barberton Mountain is also known as Makhonjwa Mountains that stretches around 120 kilometers in South Africa. Many geological scientists around the world had made a trail on the mountain in search of old rocks to decrypt the history of our beloved planet. The mountain was designated as World Heritage site right after the discoveries of such rocks.
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