Prof. Denyse Lemaire
1. What are the relationships among Earth's mantle, crust, asthenosphere, and lithosphere?
The core is divided into three major compositional layers. The crust on Earth’s surface, the rocky mantle beneath the crust and the metallic core which is the center of the Earth. While distinct and separate parts of Earth, they are all interconnected. The metallic inner core is solid, surrounded by a liquid (molten) outer core. Most of the mantle is solid, except for a layer very close to the crust boundary: the asthenosphere. The asthenosphere is plastic-like and partially molten. On top of the asthenosphere there is a rigid layer of solid rocks called the lithosphere, formed by the uppermost mantle and the crust.
In addition to the Earth’s mantle, crust, asthenosphere and lithosphere there are also hot spots that seem to be rooted in the mantle and do not move with the plates. The movement of lithospheric plates over hot spots have created long chains of old extinct volcanos which end in an active one, in the location of the plate currently over the hot spot. These hot spots show the interconnectivity of the different regions of our Earth.
2.By what processes did the planets form from the clouds of gas and dust? What are some of the main differences between the Earth-like planets and the giant outer planets such as Jupiter and Saturn?
Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star. This explosion made waves in space which squeezed the cloud of gas and dust. Squeezing made the cloud start to collapse, as gravity pulled the gas and dust together, forming a solar nebula. Like an ice skater that spins faster as she pulls in her arms, the cloud began to spin as it collapsed. As the cloud grew hotter and denser in the center, with a disk of gas and dust surrounding it that was hot in the center but...