In this diagram, the red lines represent the edges of the tectonic plates that make up the Earth's crust. For example, iron is mined from the Earth's crust in quarries. It is a finite resource ...

When an electric current passes through a metal wire, a magnetic field forms around that wire (see diagram at right ... and generators to operate. In the Earth (see image below right), the ...

Figure caption, Lower diagram shows spectrum of light redshifted from a distant galaxy moving away from the Earth The upper diagram shows the absorption spectrum from a stationary galaxy with one ...