When I was at school – Pluto was a planet.

January 18th, 2008 | Categories: Science | Tags:

Here’s one for pub quiz fans – Name the only planet that has not yet been visited by a man made probe. Some of you will say ‘Pluto‘ and this would have been the correct answer back on 19th January 2006 when the NASA space probe, New Horizons, was launched.

Two years later and, according to some astronomers, this is no longer true because the definition of a planet was altered in 2006 and Pluto no longer fits the bill. Pluto is now officially known as a dwarf planet along with the asteroid, Ceres, and the Kuiper belt object, Eris. From what I can gather there is still a lot of controversy about this ruling among the astronomical community with lots of people arguing over which balls of rock we should designate as planets and which we should not.

A wise man once said “You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird… So let’s look at the bird and see what it’s doing — that’s what counts. I learned very early the difference between knowing the name of something and knowing something.”

Damned right! Whatever you choose to designate Pluto as, it is something we know very little about and the New Horizons team are doing something about that – and THAT is what is important here. The probe won’t reach Pluto until July 2015 – over 9 years after it was launched and yet it is traveling very quickly. As it left Earth orbit it was doing something like 35,800 miles per hour and, thanks to the assistance of Jupiter, it is now going even faster at over 50,000 mph.

When it gets there it will do things like map the surface composition of Pluto and it’s largest moon Charon. It will also look at the composition of Pluto’s tenuous atmosphere, map the surface temperature, look for rings around Pluto along with various other things. Our level of knowledge about the Pluto-Charon system will have increased by orders of magnitude which will hopefully lead to even more interesting questions for future missions to work on.

For me it does not matter what you choose to call Pluto – what matters is that in a few years time we are going to know a LOT more about that enigmatic little ball of rock which is so far away that it ties my mind in knots just trying to visualize it. Happy birthday New Horizons – I wish you the best of luck.

A combination of 2 New Horizons images taken on March 2 2007 of the Jovian moons Io and Europa.

A combination of 2 New Horizons images taken on March 2 2007 of the Jovian moons Io and Europa. The original source is here.

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