From Rosetta, with love

Philae touched down on a comet back in 2014 but what has this revealed about the Kuiper Belt?
25 August 2015

Interview with 

Professor Ian Wright, Open University


It would be extremely exciting to know why we have rocky planets in our solar system and it just so happens that there was a mission - the first of its kind - late last year that touched down on a comet to answer just this question. Ian Wright is one of the scientists involved with Rosetta, the probe that dropped Philae on to the surface of the comet 67P, and he spoke to Graihagh Jackson to discuss how the mission has progressed from its roots back in 2006...

Ian - The reason you want to go to a comet is that these are the bits of debris and God knows what else that are left behind from that process 4.5 billion years ago when the sun formed and the planets formed, and all the rest of it.

Graihagh - That's Ian Wright from the Open University. He's one of the scientists involved with Rosetta, a probe that dropped Philae onto the surface of a comet called 67P.

Ian - It was an object that would've come from the Kuiper belt at some point. These bodies stay in Kuiper belt for billions of years before they get kicked out. That happens because of a chance interaction of two bodies or a body getting too close to something else and then they get put on a trajectory that takes them in towards the sun and has been going around the sun for a few times ever since.

Graihagh - So, tell me the story of how this mission was dreamed up in first place and the journey of Rosetta because it's taken - well, it left back in 2004, didn't it? So, it's taken 10 years to get there.

Ian - Yeah. ESA had this very successful mission to comet Halley in 1986. Pretty much straight after that, people started thinking about what should we do next. And so, Rosetta was born as a comet Nucleus sample return mission. So, this was not merely going to go to a comet. It was going to drill down, collect the core, and bring it back to Earth. It turned out that this was technologically quite challenging. So the question was, "well, if you can't bring the sample to the instruments, can you take the instrument to the sample?" that's ultimately what we had to do.

Graihagh - When it finally did touch down, how did you feel? It must have been an incredible result.

Ian - Yeah. I was actually out at ESOC which is where the press event was. And of course, the champagne was flowing quite nicely.

Graihagh - I can imagine.

Ian - But during the course of that evening, we actually learned that the thing had finally landed. So, it was a very nerve wrecking time, very strange mix of emotions. For us, even though it was that fairly bumpy landing, we actually got our first data back.

Graihagh - What was the data?

Ian - Almost as soon as we touched down, we were going to switch the instrument on and the idea was, we'd have a sniff around what was coming up around the spacecraft whether those would be gases or dust, or volatiles or whatever. And then we spent the next few weeks and months, trying to understand what it all meant.

Graihagh - And what did it mean?

Ian - Well, straightaway, you can see some regularity in the results. We get something called a mass spectrum and it measures the masses of compounds and the amount of each mass. You can see a regularity in this spectrum which sort of straightaway leaps out. So, there's an organic polymer that we analysed which is, we believe is a formaldehyde polymer. It's very interesting in its own right because formaldehyde is implicated in various processes around the origin of life. And also, formaldehyde is detected in interstellar space. So, it looks like we've been analysing materials from before the birth of the Solar System and it's slightly humbling to sort of be doing that.

Graihagh - Yes, I can imagine quite. I suppose the whole organic and building blocks of life leads into the whole idea of panspermia, that life perhaps was brought to us from comets rather than forming on Earth itself.

Ian - Well, there's not really anything on the Rosetta spacecraft that is there to address the issue of there being life in the comet. These are relatively primitive organic compounds. These are the building blocks of the more complex molecules from which life ultimately evolved. In a way, it's far more exciting because this is what life looked like before life got going. In terms of trying to understand the origin of life, it's tremendous to have that sort of insight and information into what would've been there at the time when it happened.

Graihagh - So, 67P has been a bit of a time machine almost for us.

Ian - Absolutely. That's one of the reasons why we went to the comet and it is absolutely like looking back in time. It's tremendous.

Graihagh - If we zoom out a little bit from 67P and look at the Kuiper belt more as a whole, what can we infer, what we have learned about 67P and apply across the Kuiper belt? Is it likely that we're going to have these formaldehydes and these building blocks there too?

Ian - We can say as a starting assumption that it is, but of course, we won't know for certain until we go and visit others and study them in this kind of detail. I think the other interesting thing is to see what kind of crossovers and tie-ins that there are between the data from the New Horizons mission with what we've got from Rosetta. Certainly for youngsters, people coming in to the subject to work on those kinds of things, this is kind of work that will easily take 5 or 10 years now to accomplish.


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