When Rosetta finally caught up with and went into orbit around Comet 67P, an intensive imaging campaign began. Rosetta Mission engineer Warwick Holmes explains some of the powerful imaging technology that is on board Rosetta.
Point of interest
While images of Comet 67P were able to give scientists a glimpse of the surface features, they were also important for planning the landing spot for the Philae lander on board Rosetta (see video Landing Philae)
We went into orbit, and we started a very intensive imaging campaign where we were looking for all these new features we’ve never seen before on a comet. This was the first comet that anyone has ever gone into an orbit around or got this close to.
One thing I have to emphasise is that this image shows a nice bright white comet, OK. Well, in reality, the surface of this comet is blacker than coal dust. It’s like the toner cartridge powder you get in a photocopier. We’ve got extremely powerful and very, very sensitive cameras, which can enhance the brightness and the contrast to actually see this thing. Only 6% of the light reflects off the surface of this comet, which is absolutely invisible. If it was standing right here beside us, we wouldn’t see it – it’d be just a black nothing – so these images are truly incredible.
What we’ve done here is use coloured filters to find out what the true colour looks like. Again, we’re having to enhance it to even show it to you, but this is what the true colour of a comet looks like.
The important thing to realise too, not only is this surface jet black – blacker than coal dust – everything you’re looking at does not exist on Earth. These are not boulders. It’s frozen chunks of gaseous ice together with, maybe, amino acids. We haven’t found that out yet – we’re still looking.
So there’s a lot of carbon chemistry – a lot of polyaromatic hydrocarbons they’re called. It’s like soot, sooty chemistry and frozen gases. Even though it looks like a hard surface or it looks like it could be somewhere in Switzerland, it certainly isn’t. None of this surface, none of this chemistry corresponds to anything on Planet Earth.
And everywhere we looked, we’re seeing unusual things. There’s a very rough surface – you can see it’s very old, you know, there’s been a lot of ageing on this poor old comet. It’s 4.5 billion years old, and yes indeed, it is old.
The Science Learning Hub would like to acknowledge the following for their contribution to this resource:
Lecture video footage courtesy of the University of Waikato
Images and footage of Comet 67P courtesy of ESA – European Space Agency