Why do dwarf planets need moons

Five moons for a dwarf planet

Now moon number five has revealed itself on images from the Hubble space telescope. The fourth had been found a good year ago.

The new moon is likely to be ten to twenty kilometers tall and irregularly shaped. It moves its orbit at a distance of almost a hundred thousand kilometers from Pluto.

The astronomers are amazed that a body as small as Pluto has so many moons around it - and their orbits interlock as wonderfully as Russian dolls.

According to the most popular theory, Pluto's moons are the remnants of a massive collision between itself and another body billions of years ago.

Space engineers view the multitude of Pluto moons with mixed feelings. Because if so many moons can be discovered from Earth, there must also be many smaller, previously unknown fragments there.

The flight planners are currently investigating very carefully which orbit the NASA "New Horizons" probe will be able to fly past Pluto in 2015 - scientifically as productively as possible and at the same time as safe as possible.

The "New Horizons" have a speed of around 50,000 kilometers per hour - at this speed a piece of rubble the size of a cherry stone could destroy the probe.

Then the exploration of the outer reaches of the solar system would disappear far beyond the horizon ...

New Horizons Mission website

Comprehensive NASA information on Pluto