- An international team of scientists have found that snowcaps discovered on Pluto's mountains differed the snowcaps on Earth's mountains.
- They first determined that the 'snow' on Pluto's mountains actually consists of frozen methane, with traces of the gas being present in Pluto's atmosphere, just like water vapour on Earth.
- Pluto's atmosphere is rich in gaseous methane at altitudes. As a result, it is only at the peaks of mountains high enough to reach this enriched zone that the air contains enough methane for it to condense. At lower altitudes, the air is too low in methane for ice to form.
- Earlier in 2015, the New Horizons space probe discovered spectacular snowcapped mountains on Pluto, which seemed strikingly similar to mountains on Earth.