With a surface area less than that of Russia, and being 5.9 billion kilometers away, it is not surprising that we know so little about Pluto. Perhaps more amazing is that for being so distant and small, we know a fair amount. The only planet yet to have been paid a call by robotic emissaries from Earth, for the present, we have had to rely on telescopic data. Most recent revelations about Pluto come from the Hubble Space Telescope, whose images reveal intriguing variation in brightness across its surface (see figure). The north and south circum-polar regions are both dominated by bright areas, which are probably nitrogen frost polar caps. Like Earth's ice caps, they wax and wane with the seasons, some 62 Earth-years long there. The equatorial region is darker and redder, suggesting methane ice and tarry hydrocarbons. The brighter of the equatorial regions may be ordinary water ice, which at Pluto temperatures is as hard as rock.At a cool 40o above absolute zero (-233 oC), substances that we on Earth experience only as gases cannot remain gaseous, and condense out as solid ice on the surface. Physically and chemically, Pluto resembles the large icy moons of the outer solar system more than it resembles any other known planet. Therefore, we believe it to be very similar to Neptune's moon Triton. With an atmosphere and possible geologic activity (the brightness contrasts are greater than on Triton, suggesting some active process has been at work), Pluto may show some interesting features when we get a close look. Charon, Pluto's moon, is smaller and so harder to interpret, but having formed near Pluto, it is expected to have similar characteristics.