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How Did The Earth Form?

Scientists theorize on how rocks and minerals stuck together with enough force to actually form planets.

Earth from Space

Photo: NASA Goddard Space Flight Center (Flickr)

From NASA: "This composite image of southern Africa and the surrounding oceans was captured by six orbits of the NASA/NOAA Suomi National Polar-orbiting Partnership spacecraft on April 9, 2015, by the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument."

Dear A Moment of Science,
How did our planet form? I mean, I know it had something to do with rocks and dust and stuff orbiting the sun and clumping together at some point … but is that it? Seems kinda random.
How Did We Get Here?

Our Answer:

The main theory about planet formation is pretty much what you write. Billions of years ago, the sun’s gravity drew matter to orbit around it.

And the gravity of that material caused it to join together to form not only Earth but all the other rocky planets and objects in our solar system.

Mineral Stickiness

But there’s some doubt about how rocks and minerals could have stuck together with enough force to actually form planets. Kind of like how dry sand on a beach doesn’t naturally stick together.

So, some scientists, such as Alexander Hubbard at the American Museum of Natural History, have come up with another theory.

Basically, the idea is that before the Earth formed, the sun experienced a volatile period where it toasted most of the matter around it, including the material that would form the Earth.

Softened by the sun’s extra burst of heat, the rocky matter could have been the right consistency to clump up and form Earth and other rocky planets, including Mercury, Venus, and Mars.

Other stars have been observed going through a brightening phase, so the same could have happened to our star. And that might be how our planet came to be.

Thank you to Alexander Hubbard, American Museum of Natural History for reviewing this episode’s script.

Sources And Further Reading:

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