Earth and Theia
Charles Dickens wrote, in 1859, A Tale of Two Cities. The two cities were Paris and London.
It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way....
That was Dickens’s description of the duality of life for residents of those two cities. This article addresses a tale of two planets. Before I explain the story of two planets, I want to get all my cards on the table so my readers know about my astrophysics background. In four years of college, three years in graduate school, and four years of post-graduate work, I took only one science class, which wasn’t astrophysics. It was a ten-hour geology class. Nonetheless, astrophysics fascinates me, along with tens of millions of others who took Carl Sagan’s course on TV in the early 80s called Cosmos.
My guess is that all my readers also don’t have any degrees in astrophysics or even took a class in it. Therefore, let me share what I stumbled across on the Internet. Our solar system was created 4.6 billion years ago when our Sun, called a protostar, exploded debris into space, creating what we call today our solar system. Around 4.59 billion years ago, the giant planets, Jupiter, Saturn, Uranus, and Neptune, were formed. 4.5 billion years ago, Mercury, Venus, Earth, and Mars experienced their naissance.
The newer planets, especially the Earth and Venus, gobbled up other planets. Over millions of years, many planets have exploded when impacting other planets, reducing many planets to the 8 that we know today.
For example, Venus was hit by an extremely large planet so directly that its rotation was reversed. Our Earth was hit by a Theia, a planet the size of Mars or possibly bigger. Theia, in Greek mythology, was the mother of the goddess of the Moon. To explain the name Theia, one needs to know that Theia, the planet, crashed into the Earth. A large part of Theia\'s impact resulted in two major deposits of large low-shear velocity provinces (LLVP) below the mantle of the Earth.
Theia breaks through the Earth’s mantle.
These blobs are located deep below the surface of the Earth.
The red areas are the LLVP / blobs.
The other part of the explosion wound up in space above the Earth and coalesced into our Moon. Some experts believe the formation of the Moon took only several hours! They also know that up to 70-90% of the total mass of the Moon is from Theia. This is NASA’s simulation showing the massive collision of Theia and the Earth.
A tale of two planets parallels A Tale of Two Cities.
It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way....
Visit the On Seeing the Light page to read more about this topic.
Visit the Connecting the Dots page to read more about this topic.
Visit the Darkest Before Dawn page to read more about this topic.
Visit the Best and Worst of Times page to read more about this topic.
12/09/24