Today, NASA’s New Horizon mission made its closest approach to the dwarf planet Pluto, a journey that has been almost 10 years in the making. Launched on January 19th 2006, New Horizons has been speeding towards Pluto ever since, and at 60,000km/h it is the fastest man made craft ever built. Its mission is to investigate the Kuiper Belt at the outer edge of the solar system, which contains Pluto and its five moons but also thousands of other smaller objects. The solar system itself contains three distinct sections: the inner rocky planets, the outer gas giants, and finally the Kuiper belt – and it is this last area that has not been explored until now.
Contained within the Kuiper belt are ice dwarf planets, ancient bodies that were formed almost 4 billion years ago, but which stopped growing at a size much smaller than the main planets of the solar system. It is believed though that the 8 planets of our solar system were formed out of these planet embryos, so there is a great deal to be learned for investigating them, particularly the two largest objects in the Kuiper Belt – Pluto and its largest moon Charon.
Charon is half the size of Pluto, and the pair together can be described as a binary planet, which means they are both orbiting the same centre of gravity at a point between the two. Binary planets are believed to be common in the Milky Way, but this is the first opportunity to investigate one up close.
The Kuiper Belt is also believed to be the source of comets that have the potential to impact with the Earth, and possibly the origin of the comet which wiped out the dinosaurs. There is a theory that life on Earth may have come about as a result of one of these impacts, as the comets contain organic molecules and water ice – the building blocks for life. Through investigating Pluto, it’s moons and other objects in the Kuiper Belt NASA are hoping to learn more about comet impacts.
Before the launch of New Horizon, the best images of Pluto were taken using the Hubble Space Telescope, but since Pluto is 4.67 billion miles away the resulting picture weren’t exactly in HD.
For the past few months New Horizons has been constantly taking new images of Pluto and its moons, from distances of millions of miles rather than billions, and with each passing day the images have been getting clearer and clearer as Pluto comes into focus. When the space craft makes it closest pass, it will be able to map the surface of Pluto and provide us more information about its atmosphere, which is also believed to be slowly escaping into space.
From tomorrow, July 15th, New Horizons will start to send back its first set of data to Earth and will continue to do so until January 2016 when the Pluto encounter will officially end. In the following year it will then be decided whether New Horizons will then be used to investigate further objects in the Kuiper Belt. But no matter what information it discovers, it will be a defining moment for human space exploration.