Category: Science

The ever-intelligent Randall Parker – and never so intelligent as when he is agreeing with me! – weighs in on the space tourism debate.  Randall makes two key points in his post:

1938 was 35 years after the first aircraft flight of Orville and
Wilbur Wright on December 17, 1903 at Kitty Hawk North Carolina. Manned
space travel began on April 12, 1961 when a Soviet air force pilot,
Major Yuri A. Gagarin, made an orbit of the Earth. So manned space
travel is over 40 years old. Space travel into Earth’s orbit is orders
of magnitude more dangerous after 40 years than aircraft travel was
when it was only 35 years old….

Newer rockets have been designed in recent years and have unexpectedly
blown up on launch. Rutan’s accomplishment is not as radical as some
media reports present it for a number of reasons. First of all, whether
he has designed a safer spaceship is will not be proven unless and
until it has flown hundreds and even thousands of times without mishap.
Also, and very importantly, SpaceShipOne does not do that much. It can not achieve orbital velocity or decelerate from orbital velocity.
In my view the Scaled Composites SpaceShipOne flight was important
because it demonstrated the potential for prizes to spur innovation. It
also opens up the possibility that that dangerous orbital spacecraft
can be designed and built for much lower costs than NASA and big
aerospace companies typically spend.

Addendum: Randall’s programming work is already in outer-space!

Space tourism is romantic but is it realistic?  On the basis of 40 years of data, I argued that rockets are dangerous and show no signs of the sort of safety improvements that are required to sustain a serious space tourism industry.  Response fell into two camps, those who misunderstood the argument and those who wanted to deny it. 

David at Cronaca pointed to the continuing demand to climb Mount Everest despite a fatality rate on the order of 4 percent.  Quite right, but that is precisely my point.  At best and for the foreseeable future space travel will remain akin to climbing Everest, dangerous and uncommon.  Yes, we might see 100 flights a year but that’s not space tourism – tourism is fat guys with cameras.  Branson and Rutan, for example, have predicted that in 10-12 years, 100,000 or more "ordinary people" will fly into space.  No way.

The other type of response is well illustrated by Rand Simberg’s reply at TechCentralStation.  Simberg argues that forty years of data are irrelevant because with SpaceShipOne "everything changed."  According to Simberg, SpaceShipOne is "a complete discontinuity", "an entirely new and different approach", and yes – you saw it coming didn’t you? – "the beginning of a new paradigm."

These are statements of faith not of reason.  Simberg has no data to back these claims because none exist.  Let’s also remember that we have heard this sort of thing many times before.  As far back as the 1960s PanAm was selling advance tickets for its inaugural moon flight.  Need I remind you where PanAm is today?

I admire Rutan and I have little doubt that he has made significant advances in rocket design but what I showed in my article was that safety could have improved by a factor of ten or even 100 and rockets would still be too unsafe to support a large tourism industry.

What’s so great about space tourism anyway?  Even though an increase in rocket safety of a factor of ten is not much when considering the safety of large numbers of people it is very significant when thinking about satellite launches or temporary low-orbit launches.  A reduction of risk of this amount means much lower insurance costs that will open up space to new private development.

Will you be travelling to space anytime soon?  What about your children?  Richard Branson is betting that the answer is yes.  I think not. Space travel remains incredibly dangerous and that is not about to change.  My article at TechCentralStation, Is Space Tourism Ready for Takeoff? lays out the facts.

I am not qualified to judge the science, but this article increased my skepticism.  Thanks to Orin Kerr for the pointer.

This new vehicle is slow but it gets 4.7 million miles to the gallon.

All along the Ganga [Ganges], the major problem of waste disposal has defied the best efforts of the Ganga Action Plan set up in 1986 to solve it.  The diversion and treatment of raw sewage in the seven main cities was planned.  In Varanasi however, the 17th century sewers, the inadequate capacity of the sewage works, the increased waterflow during the monsoons and the erratic electricity supply (essential for pumping) have all remained problems.  In addition, although most Hindus are cremated, an estimated 45,000 uncremated or partially [sic] cremated bodies are put in the Ganga each year.  A breed of scavenger turtles which dispose of rotting flesh was introduced down river but the turtles disappeared.

Surprisingly, although the Ganga may be one of the world’s most polluted rivers…scientists had discovered the river’s exceptional property in the last century.  The cholera microbe did not survive 3 hrs in Ganga water whereas in distilled water it survived 24 hrs!

That is from the India Handbook, eighth edition, p.249, and here is a photo and some

What’s the most effective pickup line on a college campus? Psychologists Elaine Hatfield and Russ Clark had actors (independently judged to be attractive) approach students of the opposite sex with a variety of lines and recorded their success rates. The lines were:

1) I’ve been noticing you around campus and I find you attractive. Would you go out with me tonight?

2) I’ve been noticing you around campus and I find you attractive. Would you come over to my apartment tonight?

3) I’ve been noticing you around campus and I find you attractive. Would you sleep with me tonight?

The success rates, as reported separately in two of my favorite popular science books, Steven Pinker’s How the Mind Works and David Barash and Judith Lipton’s Myth of Monogamy:

…what a day for science – a discovery that’s been hailed as the most significant find in the past 100 years. A team of Australian and Indonesian archaeologists has unearthed the skeleton of a new species of human in a cave on the remote Indonesian island of Flores. Less than one metre tall, it’s been nicknamed the ‘Hobbit’ and it’s estimated to be 18,000 years old. Its discovery suggests early humans branched into more forms than previously thought and that there was a time, not so long ago, when two very different human species walked the planet.

That is from the Australian Broadcasting Corporation, here is the full story. Here is New Scientist.

Levels of hormone exposure in the womb helps determine which academic discipline researchers work in, a new study suggests. Perhaps surprisingly, a “female” pattern of exposure was common in scientists, while a “male” pattern dominated in the social sciences.

The survey compared the length of people’s index (first) fingers with their ring (third) fingers. This comparison is thought to indicate prenatal sex hormone exposure, probably because some developmental genes control the formation of both the reproductive system and the digits.

In the general population, men have a “digit ratio” of 0.98 on average – the index finger being slightly shorter than the ring finger. Women have a digit ratio of 1.0 on average, meaning the two fingers are the same length.

However the 107 male and female academics surveyed at Bath University, UK, had very similar ratios – 0.987 for men and 0.984 for women. This suggests the two groups were exposed to the same levels of oestrogen and testosterone in the womb.

Hormone levels also appear to predict which discipline researchers work in. Staff in the departments of chemistry, computer science, mathematics and physics all had average ratios of over 0.995 – close to the female average – despite 81% of those subjects being male.

In contrast, the staff of the social science departments of economics, education, management, social and policy sciences had an average ratio below 0.98, the male average, despite only 66% of this sample being male.

“It’s unnerving to think the profession I’m in was determined by the hormones I was exposed to in the womb,” says Mark Brosnan, the lead author from the University of Bath, UK, whose work has been submitted to the British Journal of Psychology.

John Manning, an expert on digit ratios from the University of Central Lancashire, is not surprised that hormone levels in the womb can have such an influence. “The effect of testosterone on the developing brain is organisational and permanent,” he says.

Here is the full story. In case you are wondering, one of my hands fits this story and the other does not.

The topic is entanglement, and the headline reads Quantum Quirk May Give Objects Mass.

In my post about Alexandre Grothendieck, I pointed readers to the streaming video of a brilliant lecture by Colin McLarty. I ought also have pointed to McLarty’s even more brilliant paper as well.

Alexandre Grothendieck, born in 1928, was the greatest mathematician of the twentieth century and arguably the greatest of all time. Between 1958 and 1972 he reformulated the fundamental concepts of geometry —concepts like point, space and covering (as in, “the northern and southern hemispheres cover the entire earth”) so completely that it is no longer possible to imagine what geometry would be about if Grothendieck had never lived.

In this endeavor, he collaborated with several of the world’s finest mathematicians who put their own research agendas on hold for the privilege of attending Grothendieck’s daily seminars, fleshing out his ideas, and committing them to paper. The resulting documents, totalling over 10,000 pages, revolutionized geometry, arithmetic and algebra by viewing all of mathematics from a height of abstraction at which subjects blend together, every unnecessary detail is stripped away, and essential truths are almost automatically revealed.

Today he lives alone in a cabin in the Pyrenees, tending a garden and refusing visitors.

It’s been over 30 years since Grothendieck’s abrupt retreat from civilization, and for most of that time I’ve been waiting for someone to write his biography. This is, after all, a compelling story. Its hero is a brilliant eccentric described by everyone who’s known him as a man of indescribable charisma. (It was this legendary charisma, no less than the brilliance and clarity of the Grothendieck vision, that lured so many first-rate mathematicians away from their own research for the sake of the grand collaboration.) Besides his mathematical work, he’s given us several thousand pages of introspective autobiography, philosophy and theology, including a several-hundred page proof of the existence of God. (The thrust of the argument, as I understand it: We all have dreams, don’t we? And what could dreams be, if not messages from God? And how could God send us messages if he didn’t exist? Q.E.D.)

It’s a story touched by many of the defining events of the twentieth century: a father who died in Auschwitz, a leadership role in the antiwar and counterculture movements of the late sixties, and a career abandoned at its height partly to protest NATO’s role in the funding of mathematical research—and then, to add to the drama, decades of isolation punctuated by cryptic pronouncements and long rambling screeds that, in the opinion of many former friends and colleagues, indicate he’s gone stark raving mad.

The telling of this tale is long overdue but it looks like the waiting is over. Allyn Jackson’s superb two-part article has appeared here and here, and a full length book (by Winfried Scharlau) is apparently in the works. There is also a brilliant lecture by Colin McLarty on Grothendieck’s philosophy of mathematics. Both McLarty’s and Jackson’s pieces require some mathematical sensibility. It remains to be seen whether someone will distill the Grothendieck story down to the comfort level of, say, the average New Yorker subscriber while remaining true to the spirit and breathtaking beauty of the Grothendieck revolution.

Women living with their male partners are more likely to give birth to boys than are single women. The “marriage effect” (strictly speaking cohabiting effect) is small (51.5% boys in the cohabiting group versus 49.9% in the single group) but statistically significant. The marriage effect combined with an increase in the number of single mothers may be large enough to explain the decline in male births observed in many developed countries.

The cads versus dads theory had predicted the opposite result. Cads should have more sons than dads because big cads, by their very nature, have good male genes that are ideally passed on to little cads.

Earlier Steve noted that high status parents are more likely to have sons which makes evolutionary sense because succesful males are more likely to have children than unsuccesful ones while females are likely to have children regardless, so you want to specialize in boys when times are good and in girls when times are bad. The “marriage effect” could be an expectational consequence of the same logic. If women “know” that their male partners are unlikely to be around they know that they are more likely to have low-status in the future and thus should have girls.

I have not read the original research but it is easy to go wrong. Since girls cause divorce (and presumably also separation) it is critical to measure cohabitation before conception in order to distinguish “cohabiting causes boys” from “girls cause separation.” The research claims to measure cohabitation before “birth/conception” but retrospective bias could easily cause mothers to say that the father left before the birth (or before the child’s sex was known).

Here is an article from The Economist, here is a New Scientist piece that emphasizes different factors and here is the original research ($)