2. Cold interstellar molecular clouds often contain the molecule cyanogen (CN), whose first rotational excited states have an energy of 4.7x10^-4 eV above the ground state. Three such excited states share the same energy. It is known that for every 10 CN on the ground state, about 3 are in the three excited state. To account for the data, astronomers suggested that the molecules might be in thermal equilibrium with some "reservoir" with a well- defined temperature. What is that temperature