Friday, January 27, 2006

A sale of moon dust

Lot 195, on sale at London auctioneer Bonhams earlier this week: Apollo 11 moon dust. Now you don't see that every day. When I called Bonham's to ask where it came from, the press officer said, "the moon".

Well it actually came from a laboratory technician and discussions are underway between Bonhams, NASA, and the vendor to figure out who really owns it. My bet is that it belongs to the U.S of A.

In the picture on the left, the dust sample is on the right hand side of the tube. On the other end of the tube is a cork. The sample appears to be sellotaped to the laboratory sample sheet.

Read the full article in this week's Economist:

A fall of moon dust
Jan 26th 2006
A sample collected by Apollo 11 almost goes on sale
“LOT 195 has apparently gone back to the moon. It has been withdrawn from sale.” Thus spake Jon Baddeley, head of scientific instruments at Bonhams auctioneers in London on January 24th." (more...)

Saturday, January 21, 2006

Omega-3s are good for pregnant women

This week I wrote a story about how pregnant women may be able to make their children happier, healthier and smarter by eating more fish. This was picked up quite widely in the media.

The research was reported by an American NIH researcher Joseph Hibbeln, working with a British scientist Jean Golding. The results were important because pregnant women have been warned off fish by two federal agencies in the US. This advice has since been taken up in many other countries around the world. This research suggests that this is wrong. Yes fish has trace amounts of mercury, and mercury is bad for an unborn child, but omega-3s are so essential that avoiding fish is detrimental to the child’s health.

For the worried, it is possible to buy omega-3 supplements where mercury has been removed. But supplements from a vegetable source such as flax oil will only contain one type of omega-3 and I understand that pregnant women want to be consuming all three. So fish oil, or marine algae extract with the three types of omega-3, are the thing to consume.

This research comes hot on the heels of much research that says omega-3s are vital to adult health and can affect depression, cardiovascular disease and a whole bunch of other things. Perhaps the time has come for governments to consider setting an RDA for this nutrient? As our knowledge of nutrients grows, so does the list of things that we recognise to be essential. These days folic acid is added to our cornflakes because it is seen as essential, the same may, one day, happen with omega-3s.

Anyone worried about overfishing, but want to eat fresh fish should buy small fish that reproduce rapidly and are less likely to be overfished, sardines, herring, mackerel and skipjack tuna. Waitrose in the UK sells a wide range of fish that is certified from sustainable fisheries, and there is also the American Seafood Watch program to help consumers make more sustainable choices.

There is one final, interesting, twist to this tale. Another esential nutrient, omega-6s, taken in abundance, can strip the body of omega-3s. The main omega-6 molecule is linoleic acid, and comes from seed oils such as sunflower, soy and corn (or maize) oil. So another strategy for boosting omega-3s is to eat fewer omega-6s--of which there are rather a lot in the western diet. Fewer chips or fries. Fewer fryups unless its in olive oil, or.. lard!

It turns out that there is a strong relationship between the amount of linoleic acid consumed in a diet and homicide rates, both within and between countries. One idea about omega-3s that might help explain this relationship, is that omega-3s are essential for the correct wiring of the brain, and help us to contain our more violent impulses. I mean you never see a fish-loving Japanese guy dressing up in bling and engaging in a bit of a gang shootout.

I digress. So the arrival of linoleic acid in our diet is possibly the biggest single change in the human diet since the year dot. Americans get a whopping 10% of their calories from this single molecule.

The omega point
Jan 19th 2006
From The Economist print edition
Omega-3 fatty acids are a crucial component of a healthy diet—particularly, it seems, for pregnant women wanting bright, sociable children. (more...)

Food for thought
Jan 19th 2006
From The Economist print edition
In praise of omega-3s (more... sub req)

Thursday, January 12, 2006

Astronomers in massive planet cover up!

Next week, the New Horizons mission to Pluto is due to take off. On its journey to the ninth planet one would imagine that the folks at NASA will find out lots about the tens of thousands of icy objects way out in the Kuiper belt, including that Pluto is just one of many similar-sized objects out there. Along with the recently discovered UB313, might there be hundreds of objects discovered that are the size of Pluto?

All this raises the question, once again, of what exactly is a planet. Last year, the discovery of UB313 caused astronomers to rush off to decide, once and for all, what the difference is between a planet and a not-planet. This was reported in Nature in August last year (see here). They might, says the report, decide in a week. Five months later, I decided to ring up the astronomers for a progress report.

There organisation responsible for deciding what a planet is is the International Astronomical Union, and all the head-honcho astronomers are to be found in orbit around it. One of its vice presidents explained, sorrowfully, that it all turned out to be a bit problematic.

So I called the man who headed the committee. (Remember, these are the guys at college who did double maths and physics because it was easy.) So it came to pass that I chatted with Iwan Williams, a charming astronomer at Queen Mary College. The board, he said, produced some recommendations, he said, but couldn’t decide what the definition of a planet was.

It turned out to be a difficult problem, he said. How hard could it be? I asked in amazement. Well, he said, the only thing the astronomers could agree on was that there is a difference between things that are able to hold themselves together and be spherical under the weight of their own gravity and other lumpy objects such as an asteroid and the nucleus of a comet. I wasn’t impressed with progress on the planet/not-planet issue. OK, I say, so what’s the problem defining a planet as something where gravity makes the object spherical? The problem, he replied, is that if you use this definition you get too many planets.

“Too many planets!” I exclaimed, “how many is too many?”
“Well, about 30” he said sheepishly.
“But who are you to say what the right number of planets are in the solar system?”

It turns out that astronomers quite like there being a small number of planets, it makes them special. Planetary astronomers particularly, one presumes, have a sense of superiority over their co-workers who study mere asteroids and minor moons. And it might upset the public, as well, which has gotten used to this nice nine-planet solar system. The Earth seems so much special as one of nine. But one of 30?

So later this year, at a big IAU punch up, I meet conference, in Prague, they'll have to decide. Sounds like somehow they'll make sure that we all get the "correct" number of planets that we've come to expect rather than anything that would disturb today's vision of the universe. So much for paradigm shifts and scientific revolutions. Crikey, Copernicus will be turning in his grave.

Latest: one reader writes to suggest Pluto be renamed: "the object formerly known as Pluto"

Postcards from the edge
Jan 12th 2006
From The Economist print edition

A greater understanding of the Kuiper belt will fuel uncertainty over what, exactly, a planet is

ONCE upon a time, people thought that the solar system consisted of four small, rocky inner planets, four large, gassy outer planets and an odd little runt called Pluto. Since the early 1990s, though, almost a thousand other runts have been discovered in the region of the solar system called the Kuiper belt, where Pluto resides. Most of these objects are a lot smaller than Pluto, but a few are of similar size and one called 2003 UB313 is larger. (More... no sub req)