Both the lithosphere and asthenosphere are part of Earth and are made of similar material. Lithosphere is made up of Earth's outermost layer, the crust, and the uppermost portion of the mantle. In comparison, the asthenosphere is the upper portion of Earth's mantle (which is also the middle layer of Earth). The lithosphere lies over the asthenosphere. In fact, if any material from the asthenosphere were to solidify, it would become part of the lithosphere.
Being closer to the Earth's core, the asthenosphere is a higher temperature as compared to the lithosphere and hence its rocks are plastic and can flow. In comparison, the lithosphere's rocks are more rigid. The asthenosphere is more dense and viscous in comparison to the lithosphere. The lithosphere is comprised of a large number of fragments, each of which is known as the tectonic plate. These tectonic plates are in constant motion and are floating over the plastic material underneath.
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