Chapter 5

Other planets


“The thing which has become big business now is planetary systems, finding them, seeing what they are. The difficulty for me is that I’m rather more interested in the insides of planets than what their atmospheres look like and it seems to me that most of what’s going to come from this certainly in the beginning is going to be concerned with the atmospheres.”

An unexpected astronomical discovery has been that tiny collapsed stars called white dwarfs preserve traces of the chemistry of their former planets, which have fallen into them. “Suddenly it looks as if we can actually see something of the composition of planets which have undergone fractionation,” says McKenzie. “By that I mean that they’ve separated the iron core from the mantle and probably the crust from the mantle as well. And suddenly the whole thing is opening up and again its completely governed by the observations.”

“The other thing which is obviously going to come is a great deal of information about how new planetary systems form. It’s going to depend on really big telescopes to actually resolve things and probably telescopes in space, I think. And it is going to be led by the observations. … Those observations will throw an unexpected light on ideas which are already around. They’re not in isolation, they can be worked into the general physical understanding of what’s going on. That working it in is going to be for me a really interesting enterprise. I suspect I’m now too old, I expect I’m not actually going to see much of this happen, but it looks to me as if that’s a really big thing that’s coming.”


Chart diagram of Venus from Dan McKenzie’s working file on Venus [?1994]