Our Milky Way galaxy came together nearly 14 billion years ago when enormous clouds of gas and dust coalesced under the force of gravity. Over time, two structures emerged: first, a vast spherical “halo,” and later, a dense, bright disk. Billions of years after that, our own solar system spun into being inside this disk, so that when we look out at night, we see the Milky Way.
The Earth is made of many layers. We live on the outer layer, a thin layer of rock and water floating on an ocean of molten rocks and metals.
Main Ideas The Earth’s crust is made of tectonic plates that are floating on the hot magma below. The tectonic plates are moving, and rub against each other. This movement causes earthquakes, volcanoes, mountain ranges, tsunamis, and even geysers. Scientists think that long ago there was one huge continent. We call it Pangaea. In time, Pangaea broke apart creating the continents we have now. The Ring of Fire is a ring of active volcanoes that surrounds the Pacific Plate.
Volcanoes have existed for a long time on Earth, and they deserve our greatest respect. They may have caused major planetary disasters, such as the Permian Mass Extinction about 250 million years ago, which may have been the greatest mass extinction on Earth.
Pele, the Hawaiian Goddess of Fire—like the volcanos she represents—deserves our greatest respect. Hew beauty is awe-inspiring, her moods fiery, and her fury immense.
Main Ideas Rocks travel through a Rock Cycle, usually from igneous, to sedimentary, to metamorphic, and finally back to igneous. There are three kinds of rocks, igneous, sedimentary, and metamorphic. Igneous rocks form out of magma that is pushed up to the surface of the Earth. Three examples of igneous rock are… Sedimentary rocks accumulate in layers when particles settle out of water or air. Sedimentary rocks often contain fossils.
“Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives... a mote of dust suspended in a sunbeam... To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.”
© Copyright 2024, Ron Liskey
