Free Astronomy Magazine September-October 2015

SEPTEMBER-OCTOBER 2015 and the shades of the northern polar caps of the two globes, which are in high con- trast with the rest of the visible surfaces. The darker brown shaded areas indicate the presence of simple hydrocarbons (such as methane) and more complex molecules of the tholins class (already found some- where else in the solar system), which are formed through the action of the Sun’s ul- traviolet radiation. of its endless journey, back on Earth the Ralph imaging instrument team presents a shot of Pluto and Charon with exaggerated colour, emphasizing the complex chemical- mineralogical compositional diversities of the two surfaces (still largely to be interpre- ted). The differences that first stand out are the sharp dichotomy between the two lobes forming the “heart” (of which the easternmost appears considerably darker) 14 July, LORRI takes this shot of a geologi- cally interesting region of Hillary Montes. [NASA/ Johns Hopkins University Applied Physics Laborato- ry/Southwest Re- search Institute]