John O'Keefe, planet scientist

I've received a wonderfully evocative comment, which deserves a post of its own, on an earlier piece I wrote here about the YORP effect.

I ended that post with these words: "I still want to know more about Yarkovsky, O'Keefe, Radzievskii and Paddack."

Well this morning that request was answered when I got this from Mary:

“O’Keefe was my father. He was also responsible for discovering that the earth is (slightly) pear shaped, for which reason, we received many lugs of pears for Christmas for several years. He figured out how to map China when going from flat to round was unusual (during WWII) and he figured out that a satellite would help us to map the earth. He said tektites were from the Moon, and when nobody would listen, we put it on his funeral program so he’d have one more chance. He liked Wyeth and always talked about his appreciation of how light looks red when it comes through smoke or fog, but looks blue if it bounces off. I found his earliest comments about this in a letter to my mother before they married; he had read Goethe’s Farbenlehre.

“He believed very strongly that, as a civil servant, he was in the employ of the citizens of the US, who had a claim on his attention. Therefore those who wrote to him always received polite answers, even the little old ladies who wanted him to repent of his belief that the earth is round, or that it circuits the sun.

“He always wanted to be an astronomer; now he has an asteroid and an astral effect named after him. Good.”

Trident Times

Real science is about people too.

As Des Browne strides up to me and demands to know who I am, the answer momentarily escapes me. It is on the tip of my tongue and will come to me in a minute, I am sure. But whoever I am, I suddenly realise, this close to Britain's combative Minister of Defence is not where I would like to be.

The occasion is a debate about the morality of replacing Trident, organised by one of Browne’s constituents, Father Joe Boland of St Matthew’s, Kilmarnock.

In opening the debate the priest had done a fine job of demolishing the pro-nuclear arguments. “The government says we don’t know what the world will be like in 30 years’ time, so we need nuclear weapons to keep us secure. But if nuclear weapons equal security, then every country in the world should have them.

“If Iran cannot have nuclear weapons when faced with an immediate threat from nuclear powers, what right have we, based on some future threat? It is sheer hypocrisy.”

Deterrence is doomed to failure, he points out, because it must work without error until the end of time. “We have been incredibly lucky so far.”

When Browne stands up he looks edgy but determined. The politics are complex, he says, and the morality unclear. We must resist more countries getting nuclear weapons, while those that already possess them disarm gradually and multi-laterally.

“That is the answer to the charge of hypocrisy. That is how we will achieve a nuclear-free world.”

In the meantime, deterrence is no more complicated than self-defence, he says. “I learned when I was young that if I didn’t want to fight I had to carry myself in a particular way. I had to generate a sense, on the streets of Scotland, that I could look after myself.”

He still does, I realise, after he has lost the vote and sees me taking notes of a conversation with one of his constituents, Sarah McKee. On the topic of hypocrisy, she is challenging him on accepting the minister of defence post, after attending a rally against the invasion of Iraq.

“I wasn’t there. You are wrong about that,” he tells her.

She starts to ask about his youthful support for CND, when he sees my notebook and strides purposefully towards me. I identify myself and ask him a question – not the best question to ask a man who already feels under attack.

“I didn’t realise until today that you were brought up as a Catholic …” I begin. But he interrupts, moving closer.

“What's that got to do with anything?” he demands.

“I was wondering about Father Boland’s closing remarks,” I explain. “That in the end his opposition to replacing Trident springs from his Christianity. Jesus taught us to turn the other cheek, to love our neighbour. He would never have supported nuclear weapons.”

Browne responds that the churches disagree on war and nuclear weapons. Some support unilateral disarmament. Some don't. Then he goes on the attack.

“Are you a Christian?” he asks me.

“No,” I say. So he changes tack.

“Were you in favour of intervening in Kosovo?”

“Yes.”

"Bosnia?"

"Yes."

“What about Afghanistan?”

“Well…” I prevaricate.

“There you are…” he says and I misunderstand.

“Don’t give me that lawyer’s stuff about having to answer ‘yes’ or ‘no’," I say, annoyed. "Afghanistan was complex, militarily and politically.”

“Of course it was. That’s my point,” he replies. “International issues always are. It’s all very well saying ‘nuclear weapons are morally wrong’. But we live in a dangerous and complex world.”

True enough, I think to myself, casting my mind back 25 years to when I was a physicist with a young family, working for Rolls Royce & Associates in Derby. Working on the next generation propulsion system for the Navy’s nuclear submarines. The system that now propels the largest, most powerful submarines ever built in Britain.

The system that carries Trident.

But there is no more time for debate. The parish priest and the Minister of Defence have to leave. They are dining together this evening in the priest’s home.

“Nice talking to you,” Browne says, offering his hand.

I take it. His grip is firm but not crushing.

Deterrent.

Alphabet soup

This story exposed a few gaps in my knowledge. Until it crossed my desk, I’d never heard of the YORP effect, nor indeed of the separate scientists whose fortunately varied surnames form the acronym – Yarkovsky, O'Keefe, Radzievskii and Paddack.

Just imagine if they’d been called Blane, Underwood, Radzievskii and Paddack. Or Yarkovsky, Edwards, Lang and Paddack. Or … but you get the idea. Wouldn’t have worked at all.

Makes you wonder if just a couple of them discovered the effect, then signed the other guys up to get a good acronym out of it.

This is not as daft as it sounds. Physicists are not always grown-up and sensible. In fact as a good rule of thumb if you’re talking to a scientist who seems very serious, he’s either not a physicist or his dog just died.

One of the most famous science papers of all time is known as the alphabet article, because it was authored by Ralph Alpher, Hans Bethe and George Gamow – α, β and γ being the first three letters of the Greek alphabet.

The paper was actually written by Alpher, who was studying for a PhD at the time. Gamow his supervisor thought it would be a good joke to add the name of his buddy Bethe, who hadn’t been involved.

The young graduate student did not appreciate the humour. The presence of two eminent physicists’ names on his work meant his contribution to the important research it reported – on the origin of the Universe – might not get the recognition it deserved. He was right.

Mathematicians generally aren’t as human as physicists. They spend most of their time away from real science, in a Platonic world of beautiful objects the rest of us can’t even see. But sometimes they too get supposedly humorous ideas for papers. (If this one seems a bit rarefied, follow the links to Bacon number, which is back in something like the real world again.)

I digress. In trying to figure out the science behind the press release on YORP and the asteroid 2000 PH5, I couldn't see at first how sunlight could produce the asymmetric force needed to give it a turning moment. Then I realised it’s a small asteroid, on which gravity is far too weak to produce a smoothly spherical object – and the science started to make sense:

The Cornell astronomers bounced radar off the little chunk of rock to build a 3-D picture of it. Together with its temperature and the thermal properties of the material it’s made from – as well as distance from the sun and solar radiation output – this enabled them to calculate a value for the asymmetric force and hence the torque. Its moment of inertia – again from the 3-D model – then let them predict its rotational acceleration.

Meanwhile the optical guys were using tiny changes in brightness to actually measure its rotational velocity and, over a long period of time, rotational acceleration.

Comparing the calculated with the measured values of this allowed the scientists to test the hypothesis that it was the YORP effect that was speeding up the spinning. The agreement was good, so they announced the first observation of YORP in action on a body in the solar system.

Nice.

I still want to know more about Yarkovsky, O'Keefe, Radzievskii and Paddack though.