Pluto: Why So Smooth?

Fantastic news, Science Fans! It took it's sweet time (about 4.5 hours at the speed of light) but we finally got the first data from the New Horizons spacecraft. And even better than that: there is already a genuine mystery to puzzle out. So far we have two great pictures and some data on methane density.

The first picture, below, is of Pluto itself; it is a close up of the now famous 'heart' region. For scale, some of these peaks are about 11,000 feet high, which is comparable with mountains here on earth. What is interesting is that there are hardly any craters at all in this picture. It's very unlikely that this is because Pluto hasn't been hit by any meteors so we have to conclude that it means this surface is a very new one, and when we say very new here we mean about 100 million years old. Therefore, in the recent geological past, a process must have occurred to create this new surface. Generally this could be achieved by the planet being geologically active, like the earth is, with earthquakes and volcanoes and such churning up the place and destroying any evidence of crater impacts; or, a very large mass nearby can literally cause tides in the rock that cause them to grind and move and create heat again destroying any impact craters that might be around. The problem is that Pluto is both too small and cold to be geologically active and there is nothing large enough nearby to create tidal forces. We have a mystery.

The next picture, below, is of Pluto's largest moon, Charon, and here we see the same puzzling phenomenon. It's surprisingly smooth, there aren't all that many obvious craters; conjure (or Google) an image of our pock marked moon for comparison and the lack of craters will be much more obvious. The same argument applies here as to Pluto and we simply don't yet have an explanation. I guess it's not completely impossible that just by chance the two bodies have avoided impacts for several billions of years, but given that we know the Kuiper belt, of which Pluto is a part, is chock full of rocks and potential meteors this really does seem extremely unlikely. Do not, however, be disheartened. If there's one thing that scientists like it's a mystery. If you ask a question and the answer doesn't throw up at least a dozen new questions then you're doing it wrong.

These images are just the first tranche of what will ultimately be a deluge of data, frustratingly most of that is still on the New Horizon's craft and it will take weeks or even months for it all to be beamed back home. These initial images will have to keep us busy for a little while but one thing is for certain; we have lots of new and exciting discoveries to make about our former planetary cousin.

Pluto Revealed

I, for one, am excited. 3,462 days ago a rocket was launched carrying the New Horizons spacecraft. Its mission was to conduct the first ever flyby of the planet Pluto. Yes, that's right, the planet pluto. Back then it was still a planet but as every 8 year old but few 38 year olds know Pluto was reclassified as a dwarf planet in 2006 and we now have a solar system with 8 planets in it. The problem was that we started to find a lot of other objects out there that were about the same size as Pluto so, if we were going to keep pluto, then we would have to make room for these other objects too and very soon we might have a solar system with a couple of dozen planets in it. Good luck getting the 8 years olds to memorise all those.

Anyhoo, Pluto being so very small (only a couple of thousand kilometres across) and receiving only about one thousandth of the sunlight we enjoy it is quite difficult to see. Even when we point the mighty Hubble space telescope at it we fail to get images with any great detail in them. The image on the right was the best we had until new Horizons started edging closer in the last few weeks.

Then last weekend, at a distance of about 1 million miles from Pluto, the image below was beamed back from 3 billion miles away. The increase in resolution is marked and will have the Geology, Geophysics and Imaging nerds at John Hopkins university very excited; as it will all of us interested in going boldly where no one has ever gone before. And the best part? It's only going to get better. The craft will pass within 8,000 miles of the planet's surface today and, asides, from all the cool science that will be done, should take some pretty awesome pictures before speeding off into the outer solar system at 50,000 miles per hour.

Images courtesy of NASA

365 Project: Photo 295

A night out with workmates inevitably ends with me going for a walk along the river. Conveniently, the theme was Dark. This was taken on my phone, when drunk, from the Millennium bridge. The bright star above the moon is, in fact, Jupiter.

365 Project: Photo 251

The crescent moon was wonderfully thin tonight; and, if you look carefully, up and to the left you will spy the planet Venus. The focus is a little soft but this was handheld so not too bad.