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The big bang is how astronomers explain the way the universe began. It is the idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now—and it is still stretching! This happened around 13.8 billion years ago -
Solar system formation began approximately 4.5 billion years ago, when gravity pulled a cloud of dust and gas together to form our solar system. -
In a wide expanse of space, gravity drew dust and gas together to create the young solar system. The sun formed first from the vast material, with the planets close behind. It was created at the same time as our sun. -
Planet earth is 4.6 billion years old. It was formed the exact way the sun was. -
The moon was formed 200 million years ago. -
Unicellular life first appeared 558 million years ago. -
Multicellular life started around 400 million years ago. -
Dinosaurs started between 245 and 66 million years ago. -
Humans appeared around 300 thousand years ago.