Another Near Miss

In case you missed it, asteroid 2009 DD45 passed the Earth today at a distance of about 1/7th of the way to the moon. It was noticed about 3 days ago, and apparently has an orbit that will bring it close to home every so often. See here. It is relatively tiny, about 30 meters across. Therefore, when it hits it'll only make a hole a few miles across. Maybe the size of Manhattan or the Greater Chicago area. Yes, when. It'll probably hit in the ocean, in which case only seaside towns will be destroyed, like Miami, D.C, or Los Angeles. But this is only one of thousands that have been discovered so far. No need to worry. When the sky does fall, we'll find out eventually. With a bit of pork barrel spending, we might be able to predict and prevent such things. But it might cost as much as the current bailing out of mismanaged banks. But I've discussed the end of the world before.

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Isaac Asimov talks with Bill Moyers

This video was created many years ago--based on Moyers' description of the American space program, it was probably made in the early to mid 1960's. I had never before seen any video of Asimov (though I have read some of his writings), and I found this video (part of an episode from "Bill Moyers World") to be engaging. The topics: science and education. I also found what appears to be a full transcript of the interview at Harpers Magazine, which contains some additional information, including this exchange on the power and limits of science:

MOYERS: What's the real knowledge?

ASIMOV: We can't be absolutely certain. Science doesn't purvey absolute truth. Science is a mechanism, a way of trying to improve your knowledge of nature. It's a system for testing your thoughts against the universe and seeing whether they match. This works not just for the ordinary aspects of science, but for all of life. I should think people would want to know that what they know is truly what the universe is like, or at least as close as they can get to it. We don't pretend that we know everything. In fact, it would be terrible to know everything because there'd be nothing left to learn. But you don't want to be up a blind alley somewhere.

As you might assume, Wikipedia has an informative biography on Asimov. After viewing this video, I looked it up. I especially enjoyed his comment on religion:

In his last volume of autobiography, Asimov wrote, "If I were not an atheist, I would believe in a God who would choose to save people on the basis of the totality of their lives and not the pattern of their words. I think he would prefer an honest and righteous atheist to a TV preacher whose every word is God, God, God, and whose every deed is foul, foul, foul." The same memoir states his belief that Hell is "the drooling dream of a sadist" crudely affixed to an all-merciful God; if even human governments were willing to curtail cruel and unusual punishments, wondered Asimov, why would punishment in the afterlife not be restricted to a limited term? Asimov rejected the idea that a human belief or action could merit infinite punishment. If an afterlife of just deserts existed, he claimed, the longest and most severe punishment would be reserved for those who "slandered God by inventing Hell."

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Why do women in wealthy societies have fewer children?

I’ve often wondered why women in wealthy societies have fewer children. Melanie Moses (who teaches Computer Science at the University of New Mexico) offers a solution in an article entitled, “Being Human: Engineering: Worldwide Ebb,” appearing in the 2/5/09 edition of Nature (available online only to subscribers). This phenomenon is counter-intuitive because evolution by natural selection would seemingly predict that human animals with more resources would have more babies. Moses employs the Metabolic Theory of Ecology (MTE), an approach for understanding the dynamics of flow through networks. It was developed

to explain why so many characteristics of plants and animals systematically depend on their mass in a very peculiar way. . . According to the theory, the larger the animal, the longer its cardiovascular system (its network of arteries and capillaries) takes to deliver resources to its cells. That delivery time, which in turn dictates the animal's metabolic rate, is proportional to the animal's mass raised to the power of ¼. Thus, because its circulatory system works less efficiently, an elephant grows systematically more slowly than a mouse, with a slower heart rate, a lower reproductive rate and a longer lifespan.

Moses argues that this idea that networks become predictably less efficient as they grow has “profound” consequences. With regard to fertility, she starts with facts regarding our energy consumption.

The average human uses up only about 100 watts from eating food, consistent with predictions based on body size. But in North America, each person uses an additional 10,000 watts from oil, gas, coal and a smattering of renewable sources, all of which are delivered through expansive, expensive infrastructure networks.

How do energy networks interact with the reproductive choices of humans?

The decline in human birth rates with increased energy consumption is quantitatively identical to the decline in fertility rate with increased metabolism in other mammals. Put another way, North Americans consume energy at a rate sufficient to sustain a 30,000-kilogram primate, and have offspring at the very slow rate predicted for a beast of this size . . . As infrastructure grows we get more out of it, but must invest more into it, reducing the energy and capital left to invest in the next generation.

Moses disagrees with alternative explanations, such as availability of birth control or decisions to marry later, because these don’t explain decisions to have fewer children in the first place. She also dismisses the idea that “as societies become wealthier, greater educational investments are made in each child to make them competitive in labour markets” because investments in eduction correlate inversely with fertility rates.

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All-too-human art

In a recent article appearing in Nature, "More Than Skin Deep," Martin Kemp asks what we are to think of Andrew Krasnow's work of art entitled "Flag from Flag Poll." The artwork is a 2 meter long American Flag made out of human skin. Consider, also, the online exhibit entitled "Making Visible Embryos," by Tatjana Buklijas and Nick Hopwood. In Nature, Alison Abbott describes the exhibit as "the story of how embryos have been depicted."

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The co-founder of Twitter talks about the Twitter phenomenon at TED

Twitter, undeniably addictive to at least some of its advocates, has only been around since early 2006. The co-founder of Twitter, Evan Williams, talked for eight minutes at TED about his product. Twitter was originally invented as a means for sending "simple status updates to friends." It allows you to say what you're doing in 140 characters or less, with those people interested in you able to get those updates. According to Williams, Twitter "makes people feel more connected and in touch, sharing moments as things happen." It allows your friends "to know what it's like to be there." Twitter use is exploding. It's now ten times bigger than it was at the beginning of 2008. According to this entry at Wikipedia, Twitter has 55 million monthly visitors. Williams concludes his talk by noting that some Twitter users have used Twitter to enable real-time mass-action by armies of fellow Twitter users. I''ll confess that I'm not a Twitter user (though I did set up an account due to the constant urging of a real-life friend, but I haven't actually used it). I don't think I'll ever be a Twitter addict based on what I know about Twitter. I prefer writing in paragraphs rather than writing chopped up sentences. I don't want real time commentary,even from my closest of friends--I'd rather you save it up a bit and then we spend quality time together exchanging our stories with more context and color. Also, I like to get away from my computer and phone for long stretches--I recharge by getting totally away from people. I'm also suspicious that many people are deluding themselves that their on-line contacts are true "friends," in that we don't have the that kind of cognitive capacity. None of this is to deny that Twitter might sometimes be useful, even possibly life-saving in times of national crisis. I suspect, though, that Twitter is mostly word fidgeting--an addiction seemingly important due to the powerful illusion that motion--doing anything--constitutes progress. I'll admit that many important inventions were derided in the early-going (e.g., the telephone). I might be wrong when I demean Twitter as a serious mode of communication. Writing about Twitter reminds me of a recent book in which each author attempts to capture his or her entire life in six words or less. Without further ado, here's that eight-minute speech by Evan Williams, the co-founder of Twitter.

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