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1️⃣ How old is the Earth?

• Earth is about 4.5 billion years old.
• That means 4,500,000,000 years — a very, very long time!

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2️⃣ How do scientists know this?

Scientists use rocks to find Earth’s age.

• Some rocks are as old as the Earth itself.
• Scientists study radioactive elements in rocks.
• These elements change very slowly over time, like a natural clock.

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3️⃣ What is radioactive dating?

• Certain elements slowly change into other elements.
• By measuring this change, scientists can tell how old a rock is.
• This method is called radiometric dating.

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4️⃣ Earth was very different at the beginning

• Early Earth was hot and molten.
• There were no oceans, plants, animals, or people.
• Volcanoes and meteor impacts were common.

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5️⃣ Life appeared much later

• First life forms appeared about 3.5 billion years ago.
• These were tiny single-celled organisms.
• Plants, animals, and humans came much later.

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6️⃣ Humans are very new!

• Modern humans appeared only about 300,000 years ago.
• Compared to Earth’s age, humans are newcomers.

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7️⃣ Easy comparison to understand time ⏳

If Earth’s history were 1 year:

• Life appears in March
• Dinosaurs appear in December
• Humans appear in the last few minutes of December 31

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🧠 Key takeaway

Earth is 4.5 billion years old, and scientists know this by studying ancient rocks and natural clocks inside them.

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