In this episode of Richard Garriott's miniseries, he shows us how Earth formed, how remnants of that formation still wander the solar system and how our planet came to be covered by oceans.
Next week: Life on Earth Begins
Hi. I’m Richard Garriott. And we’re standing before our Cabinet of Curiosities about the history of the universe.
Our sun came into existence—it first turned on its nuclear furnace—about five billion years ago. About 4.6 billion years ago planets like our Earth formed out of the ever-growing clumps of debris that were in the accretion disk around it. And a lot of those clumps of debris still exist and are orbiting the sun as asteroids, and some of those fall to the Earth as meteorites.
Well, here is a meteorite that fell to the Earth some years ago. We can tell that this came from space both because of the fusion crust you can see that formed from entering the Earth’s atmosphere at something like 30,000 miles per hour.
But there is another way as well. If you slice these meteorites and polish up the surface, you can often see these crystalline structures in iron. If you were to melt this here on Earth at one gravity and re-cool it again, you wouldn’t grow these crystals. Much the same way as you can grow complex snowflakes with moisture floating in the air, you rarely see such complexity when you freeze ice in the ice tray at your home.
Collisions that occur between asteroids and planetary bodies continue to this day. And sometimes collisions are big enough to knock debris off of things like our moon, Mercury and Mars, throw them into space, where they come down on the Earth as meteorites.
For example, this is a slice of a meteorite that fell to Earth that we know came from the surface of the moon. Similarly we can find meteorites that have come from the planet Mars. And there are even some that are now believed to come from the planet Mercury.
So, as the Earth cooled from being this complete ball of molten lava, fairly soon, the moisture that was on the surface of the Earth began to condense into water, came down as rain and ultimately formed oceans. So this is what the early Earth looked like when there was really land and water—but no life.
Previous episode: The Big Bang
Next episode: How Early Life Turned Earth into a Giant Snowball
