That is, if you observe the spectrum of a star and can determine the wavelength where the emission peaks (Î»max), you can calculate that starâs temperature. Here is another copy of the plot that we studied in Lesson 3: Figure 4.1: Two-dimensional plot of the spectrum of a blackbody with different temperatures.
Igneous rocks usually contain the most crystals. The longer it takes the magma to cool, the larger the crystals.
Examples: granite, gabbro, diorite, peridotite. Extrusive rocks are formed from magma at or above the surface of the planet, and generally display smaller mineral crystals, or no crystals at all, because of the rapid cooling environment in which they form.