Formation of the Moon, Nebulae, Tectonics - SCI S2A Stage 9 Unit 6.3-6.5

TB DEFINITION: Nebulae are vast clouds of dust and gas in space.

A nebula is a vast, interstellar cloud of dust, hydrogen, helium, and other ionized gases located in space. Often referred to as "star nurseries" or "stellar graveyards," they are regions where new stars are born, or where dying stars have expelled their outer layers. These clouds can span hundreds of light-years and are visible due to light from nearby stars reflecting or emitting from the gas.

What are nebulae?

Tectonic plates are large, rigid slabs of solid rock composing the Earth's outer shell, known as the lithosphere (crust and upper mantle). Fitting together like a puzzle, these plates float on the semi-liquid asthenosphere below and move roughly 1–10 cm annually, creating earthquakes, volcanoes, and mountains at their boundaries.

What are tectonic plates?

The giant-impact hypothesis posits that the Moon formed approximately 4.5 billion years ago when a Mars-sized planet named Theia collided with the young Earth. The impact ejected vast amounts of debris into orbit, which coalesced (come together to form one mass or whole) to form the Moon, explaining its similar composition to Earth and its iron-poor composition.

What is the Collision Theory for the Formation of the Moon? (Or the Giant Impact)

Tectonic plates move primarily due to intense heat from Earth's core causing convective currents in the mantle, which rise and drag plates, along with gravity pulling dense plates down (slab pull) and pushing plates from mid-ocean ridges (ridge push). These forces, acting over millions of years, cause plates to converge, diverge, or slip past each other.

What causes tectonic plates to move?