Structure of the Earth easily than does the upper mantle (chemical changes within the mantle may also be important). The viscosity of the mantle ranges between 10 and 10 Pa·s, depending on depth. In comparison, the viscosity of water is approximately 10 Pa·s and that of pitch is 10 Pa·s. The source of heat that drives plate tectonics is the primordial heat left over from the planet’s formation as well as the radioactive decay of uranium, thorium, and potassium in Earth’s crust and mantle. The average density of Earth is . Because the average density of surface material is only around , we must
Evacuate Earth propose that colonists will eat insects and algae, which are easily replenished and space efficient. The ark ship launches and quickly speeds away, a few days later the neutron star is close enough that its tidal force begins to deform the Earth's core and the crust, which causes massive earthquakes and volcanism. Next, the gravity from the neutron star tears away the surface, causing the crust to shatter and the hot interior of Earth to spill out into the vacuum of space, destroying the Earth, but only the colonists on the ark can witness this event, as the rest of