Mercury's is formed from sodium atoms being blasted free of its 'exosphere' (like an atmosphere, but too thin to behave like gases), and then fluorescing, due to cosmic radiation (like our polar auroras).
www.sciencealert.com/the-tail-of-...
Mercury's is formed from sodium atoms being blasted free of its 'exosphere' (like an atmosphere, but too thin to behave like gases), and then fluorescing, due to cosmic radiation (like our polar auroras).
www.sciencealert.com/the-tail-of-...