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.
Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental plates approximately 335 million years ago, and it began to break apart about 175 million years ago. Pangaea was centred on the Equator and surrounded by a huge ocean. Pangaea is the most recent supercontinent to have existed and the first to be reconstructed by geologists.
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.
There are three main types of rocks: igneous, sedimentary, and metamorphic. Each of these rocks are formed by physical changes—such as melting, cooling, eroding, compacting, or deforming—that are part of the rock cycle.
Create a supersaturated solution. As the solution becomes unstable, salt crystals will form.
Fossils are part of the cycle of life. All living being are made of matter, and when they die the matter in their bodies returns to the material world.
A fossil is any evidence of prehistoric life (plant or animal) that is at least 10,000 years old. The most commonly found fossils are bones and teeth, but fossils of footprints and skin impressions exist as well.
Fossils are excavated from many environments, including ancient riverbeds, lakes, caves, volcanic ash falls, and tar pits.
