Science!
Saturday November 25, 2006
Somehow makes even The Lord of the Rings seem short
It is hard to overemphasize the shocking suddenness of life's proliferation in the seas and on the lands of Earth. Suppose some galactic civilization had evolved on planets of stars older than the sun, and they had sent out a dozen expeditions to visit Earth, spaced evenly throughout Earth's history. The first ten expeditions would have found only lifeless craters, lavas, sand dunes, and highly eroded river channels on Earth's land surfaces. The eleventh expedition would have arrived 380 My [million years] ago and would have found the land mostly covered by flourishing Devonian forests. The twelfth expedition would find us.
From William K. Hartmann & Ron Miller's The History of Earth. Recommended as a highly readable summary of the geological and biological evolution of the planet. Mostly geology, since that's actually most of Earth's history--6/7ths of it, in fact, without any life whatsoever. Human history is even more absurdly short, about 10,000 years, compared to 4,500,000,000 years of Earth history. Which is to say the Earth has been human-free for 449,999/450,000 or 99.9998% of its existence. (By comparison, dinosaurs were around for something like 150,000,000 years--15,000 times as long as us.)
Anyway, if at this point in your life you're not completely blown away by the staggering scale of geologic time, this is a nice book to fix that.
Posted by jkwilson ( Nov 25 2006, 11:26:40 AM EST ) Permalink Comments [2]
Wednesday November 08, 2006
Transit of Mercury
Astronomy is exciting when things pass in front of other things. It can teach us a lot, like when galaxies pass in front of other things in deep space, which can cause a phenomenon called gravitational lensing. Or, it can just look really swell and give us a window into how everything is moving around out there, as in eclipses.
Today, witness a fairly rare event: a transit of Mercury across the face of the sun. You can get more information and witness a broadcast online at the Exploratorium. The transit begins about 2:15pm Eastern Time. Hopefully the webcast will be worthwhile: it's a reduced size image suitable for internet broadcast, of something already small and sort of fuzzy if you're not looking closely.
This is similar to a solar eclipse in that we'll see one object passing between us and the sun, manifesting in a shadow of that object. The difference is that while the angular size of the moon is just about that of the sun from Earth perspective, resulting in occasional total eclipses, Mercury appears much, much smaller. Like, this small (image from Exploratorium site):
I was fortunate to see the 1999 transit live through a solar telescope. But that time, Mercury just clipped the edge of the solar face. This time it will catch more of the disk from where I'm at, and will take around five hours. On the east coast, the sun will set before the transit is finished.
Posted by jkwilson ( Nov 08 2006, 10:34:19 AM EST ) Permalink
Monday October 30, 2006
Little chocolate donuts
My next exercise as chemistry reference librarian: look up all the dubious compounds contained in the donuts I just ate. (Ironically and idealistically known as Mrs. Freshley's Chocolate Mini-Donuts, purchased out of a vending machine. The good news is that they had an expiration date.) My short-term goal is to use library resources to understand the purpose of each of the mystery ingredients. My long-term goal is to scare myself into never being tempted to eat these things again:
sodium acid pyrophosphate
sodium aluminum phosphate
monocalcium phosphate
dextrins
guar gum
karaya gum
monoglycerides
sodium stearoyl lactylate
xanthan gum
bees wax
cellulose
enzyme [this is frighteningly vague--I'm not quite sure this counts as full disclosure of ingredients, to be honest]
sodium propionate
potassium sorbate (to preserve freshness)
Posted by jkwilson ( Oct 30 2006, 04:18:13 PM EST ) Permalink
2007 North Carolina Science Blogging Conference
I'll be going to the 2007 North Carolina Science Blogging Conference, to be held at UNC in January. If you're interested in science blogging and will be in the area, please consider attending. From the site: "This is a free, open and public event for scientists, educators, students, journalists, bloggers and anyone interested in discussing science communication, education and literacy on the Web." Have a look at the site for more details.
Should be interesting to meet some others in the area who have actual science blogs, instead of my random science news observations (on topics sometimes decades old).
Posted by jkwilson ( Oct 30 2006, 02:26:56 PM EST ) Permalink Comments [3]
Friday October 13, 2006
All nine lives used up
Genetic Savings & Clone is going out of business.
I discussed this a while ago: they were in the truly insane business of cloning cats for a steep fee. This was actually a lot of sound and fury, signifying nothing. They only cloned five cats successfully, and sold only two to paying customers. According to the AP story, they simply haven't been able to make the process commercially viable.
Posted by jkwilson ( Oct 13 2006, 11:39:22 AM EDT ) Permalink
Monday October 09, 2006
Nemesis!
Highly recommended, as a readable introduction to the process of working through from scientific hypothesis to theory, is Richard Muller's Nemesis. (By remarkable coincidence it is available in this library, or it will be, once I turn it in.)
The Nemesis theory is a fun one. Having a look at the graph below will help explain it (from Rampino MR, The galactic theory of mass extinctions: An update. Celestial Mechanics & Dynamical Astronomy 69 (1-2): 49-58):
What we're seeing here is the number of living species (represented by the rather brutal 'species kill percentage') over time. We see that there are frequent "death spikes", where large numbers of species perish all at once. It turns out these even happen with some regularity, something like every 26-30 million years, depending on how much you trust the age measurements of the fossils. You can see that the death spikes are often accompanied (especially in more recent times, when they're easier to find) by signs of comet, asteroid, or meteor impacts--leaving behind craters and iridium and kicking up dust ("ejecta").
The fact that the impacts are happening fairly regularly isn't really the subject of debate any more (Muller's book takes you through some of the early discoveries of these impacts). But the cause and exact frequency of the impacts is another matter. Why are we getting bombarded with such regularity? It can't be coincidence.
Muller and his colleagues originally came up with the idea of Nemesis, a theoretical companion star to the sun. When it approaches every 26 million years or so, it wrenches a bunch of comets out of their stable, distant lives in the outer solar system, and sends them hurtling towards the sun, some of which will eventually impact Earth. The book takes you through the development of the hypthosis as he rules out several potential alternate theories, debates evidence with other teams of scientists, and fights to prevent the mass media from completely getting it wrong or embarrassing him. It's a great window into the world of scientific discourse. How are theories developed? How are they disproven? How do teams of experts in different fields effectively work together? What happens when another reputable team has a different theory? How do "nutty" theories gain respect, and how does any theory stand up to scrutiny?
The book was published in 1988, so it's somewhat dated, but the theory itself is still around and depending on what you read, appreciating about the same level of moderate acceptance. It's left with Muller preparing to search for the Nemesis star, and nearly twenty years later it has still never been definitively identified--making it easy to write off the theory. Detractors also usually cite a lack of evidence for the periodicity of the extinctions (despite the graph seen above, the dating isn't entirely accepted), or insufficient proof that Nemesis could have a stable orbit with respect to the sun. The most commonly-studied alternate theory these days is that the solar system actually oscillates up and down with respect to the galactic plane while it orbits around the galactic center, and when it crosses this plane (every 26 million years), the extra mass of dust and gas nearby is enough to perturb some comets. Muller actually considers and dismisses this theory within his book. So, the matter is hardly settled.
Anyway, while it's obviously not helpful to the theory that no candidate star has been found, it's not hopeless either--such a star would be very small and currently is at its furthest from our solar system. So the good news is that if we believe the theory, the "putative death star" (as geologist Eugene Shoemaker referred to it) is a good 10-15 million years away from a return trip.
Posted by jkwilson ( Oct 09 2006, 05:18:39 PM EDT ) Permalink
Friday October 06, 2006
2006 IgNobel Prizes
Last night was the Academy Awards...of bizarre research, also known as the IgNobel prizes. I can't possibly add to them with commentary.
So, view the complete list here (servers are overwhelmed this morning). And here are some of the highlights (from Reuters):
-- BIOLOGY - Bart Knols of Wageningen Agricultural University in the Netherlands, the National Institute for Medical Research in Tanzania and the International Atomic Energy Agency in Vienna, Austria and colleague Ruurd de Jong for showing that the female Anopheles gambiae mosquito, which carries malaria, is attracted equally to the smell of limburger cheese and to the smell of human feet.
"We have shown that three different Anopheles mosquito species prefer to bite different parts of a naked motionless volunteer and that this behavior is influenced by odors from those body regions," they wrote in their report, published in the Lancet medical journal in 1996.
-- ORNITHOLOGY - Ivan Schwab of the University of California Davis, and the late Philip R.A. May of the University of California Los Angeles, for explaining why woodpeckers do not get headaches.
-- NUTRITION - Wasmia Al-Houty of Kuwait University and Faten Al-Mussalam of the Kuwait Environment Public Authority, for showing that dung beetles are finicky eaters.
-- PEACE - Howard Stapleton of Merthyr Tydfil, Wales, for inventing a teenager repellent -- a device that makes a high-pitched noise that is annoying to teenagers but inaudible to most adults; and for later using the technology to make cellphone ringtones that teenagers can hear but not their teachers.
-- ACOUSTICS - D. Lynn Halpern, Randolph Blake and James Hillenbrand of Chicago's Northwestern University for a 1986 experiment aimed at discovering why the sound of fingernails scraping on a blackboard is so irritating.
-- MEDICINE - Francis Fesmire of the University of Tennessee College of Medicine and the team of Majed Odeh, Harry Bassan and Arie Oliven of Bnai Zion Medical Center in Haifa, Israel who both published studies entitled "Termination of Intractable Hiccups with Digital Rectal Massage."
-- MATHEMATICS - Nic Svenson and Piers Barnes of the Australian Commonwealth Scientific and Research Organization, for calculating the number of shots a photographer must take to almost ensure that nobody in a group photo will have their eyes closed.
Posted by jkwilson ( Oct 06 2006, 09:23:13 AM EDT ) Permalink
Thursday September 28, 2006
Peer-reviewed journals: only for l33t researchers?
From a discussion of the traditional peer-review process in scientific journals. The Public Library of Science is launching an open access journal called PLoS ONE with a new kind of peer-review model. (Nature's doing someting similar.) Instead of painstaking pre-publication review by qualified colleagues and researchers in the field (i.e., peers), they're trying this:
Articles published in the new journal will undergo peer review, but some of the standard criteria that older journals use to screen out articles--like "degree of advance" or "interest to a general reader"--won't be used by PLoS ONE reviewers; all papers of scientific merit will be posted to the public record...A more public review process will continue after publication, as readers will be able to rate, annotate, and comment on papers, and authors can respond to their comments. The original paper will remain as such, but comments, revisions, and updates will orbit nearby, an electronic Talmud on every article of significance.It's an interesting Web 2.0 approach: just get it online, and let the masses sort it out. Of course, it's not without its drawbacks:
It is easy to believe, in reading the plans for this new publication, that it truly represents "the first step" in a wonderful "revolution" (as the Public Library of Science puts it). But it is worth remembering that gates and gatekeepers serve the important function of keeping out barbarians; it would be regrettable if the world of science journals came to suffer the sort of "trolling" and "flaming" so common today in comments on blogs and Internet discussion boards. It would be unfortunate if the deliberate, measured character of scientific research and discourse were lost to a culture of speed, hype, and quick-hit comments.Flaming is certainly a concern: ever been to a conference where petty arguments *didn't* break out and go on way too long at some point? And you don't have to spend much time on internet message boards and community sites to get a feel for what happens when you give the wrong people (a) a forum to express their opinions, no matter how banal, and (b) anonymity. Imagine a world where dissertations are published online by freshly doctorated researchers, only to be met with comments like "OMG n00b!!!!1!!"
Posted by jkwilson ( Sep 28 2006, 10:57:23 AM EDT ) Permalink Comments [1]
Friday September 15, 2006
Nine Lives Extravaganza
Miss your cat? Get it back!
As near as I can tell, this is for serious, although it's clearly the most insane thing I've seen in a long time...prior to euthanization, you can pay $895 to have Genetic Savings & Clone Inc. take a biopsy sample and save it in their PetBank for $100 a year. ($1395 for the premium service--extra samples taken and the option to have the procedure done on recently-deceased pets.) Then, for a mere $32,000, they'll clone your cat, delivering you a new kitten with the exact genetic traits of your beloved feline pal. (At present, this service isn't available for dogs.)
Wow. I had no idea such a thing existed, at any price. I won't get into the ethics of cloning (their site makes some effort to do so) but I can't help but feel like they're preying on people's grief. And actually, just grieving people with a lot of extra money on their hands. Not that I want to put any price on a pet, which is often entirely a member of your family. But $32,000 could go a very long ways in the hands of the Humane Society or ASPCA. Speaking of which, they have any number of kittens and cats that you can adopt today, rather than burning a fortune on a clone. This is exceedingly wasteful extravagance.
Posted by jkwilson ( Sep 15 2006, 11:34:02 AM EDT ) Permalink Comments [5]
Friday September 08, 2006
Science prevails
I'm something of a NOAA National Hurricane Center addict now that I live in hurricane country. I mean, if you crave hurricane danger, it's hardly like living in Florida or even closer to the coast. But I grew up in Montana, where hurricanes are strictly confined to television.
I like to read the forecast discussions in particular when a storm is developing. Not that I follow a lot of the meteorological reasoning, but you can get some details about the storm's progress outside of just the forecasts and warnings. One paragraph today struck me, in discussion about Tropical Storm Florence, which has failed to organize and develop the way that many of the models have predicted. Yet the forecaster is still confident (emphasis mine):
NOTE: LAST TWO VISIBLE SATELLITE IMAGES PRIOR TO SENDING THIS
ADVISORY SUGGESTS THAT THE CLOUD PATTERN IS A LITTLE BETTER
ORGANIZED AND THE CENTER APPEARS TO BE TUCKED INTO THE CONVECTION.
IF THIS TREND TOWARD ORGANIZATION CONTINUES...SCIENCE WILL HAVE PREVAILED.
This is signed at the end by Forecaster Avila, whose brief wikipedia page highlights his other forecasting greatest hits. I guess I'm just always surprised when there's any levity in these discussions. The all-caps type (and often, the warnings of impending weather catastrophe) are otherwise so serious...
Posted by jkwilson ( Sep 08 2006, 02:19:55 PM EDT ) Permalink
Wednesday August 23, 2006
Orbital dominance!
The planet debate continues at the IAU 26th (or XXVIth for you Romans) General Assembly. Interesting update today about the status of the draft proposal for a definition of a planet, released last week but subject to discussion and vote before becoming official. In short, all your effort to create new 12-word mnemonics for remembering the planets has probably been for naught.
The main problem with the draft was that the definition was just too inclusive. The liberally small size requirement could have potentially let several asteroids and Kuiper Belt Objects (KBOs) into the intentionally exclusive club of planethood. Instead, the concept of orbital dominance has emerged from the conference as a better way to distinguish planets from everything else in the solar system. If an object is the only major body in its orbit, that should count for something. This concept lends weight to the nature of first eight planets, recognizing them as unique objects. However, it eliminates Pluto. Given that Charon is significantly close to Pluto in mass, neither is considered dominant. It also pretty much slams the door on finding any other planets, a possibility the draft definition made very likely.
So, Pluto, Charon, 2003 UB313, and other distanct KBOs will probably be banished to dwarf planet status. Astronomers are still discussing possible names for these objects to separate them from asteroids. The term "plutons" has already been dismissed. "Pluton" is actually already a common geological term for igneous rocks (solidified magma). I like this take on it, from the AP article:
"What were they thinking? The reaction in the geologic community was rolling of eyes," said Allen F. Glazner, a geologist at the University of North Carolina. "It would be like botanists trying to distinguish between trees and shrubs and coming up with the term 'animal.'"
I liked the 12 planet idea, but I think I'm happier with this definition. The draft doesn't differentiate "major" planets, KBOs, and asteroids, just lumps them all together in one big happy planet family. But I like orbital dominance, and using the word planet to mean something significant. I'm guessing large, spherical objects in the Kuiper belt (i.e., Pluto and Friends) will end up being called Tombaugh Objects as a political way of recognizing Clyde Tombaugh's discovery of Pluto. Seems nice, given that they're stealing a whole planet from him.
You also have to feel for the astrology community, who must have been primed for the 12-planet system. It would have given them ready-made excuses for thousands of years of mistakes. ("No, see if we'd have known about Ceres, we could have predicted you'd miss out on that big promotion!")
Posted by jkwilson ( Aug 23 2006, 05:04:32 PM EDT ) Permalink Comments [1]
Wednesday August 16, 2006
Everything you know (about planets) is wrong
Right now the International Astronomical Union (IAU) is convening for their 26th General Assembly (or the XXVIth for you Romans). Among their tasks is to formally define the idea of a planet and in turn, decide just how many planets are in this solar system, anyway.
Today they've drafted a resolution which creates not only a definition for planets, but includes a definition for a new class of object called a "pluton" (including Pluto, its companion Charon, and the as-yet-unnamed 2003 UB313, an object similar to Pluto that's probably a bit larger but further away). Should these definitions be accepted by the mass of eager astronomers, we'll suddenly have twelve planets!
Image from here.
We're due for such a discussion, officially. Modern observational techniques continue to find new examples to confound the generally accepted idea of a planet. 2003 UB313 (popularly called "Xena" but the IAU won't touch that one--anyway it's not "official" yet) is at least as big as Pluto but has a much more eccentric orbit. And astronomers regularly find new objects beyond Pluto (an area with a great deal of dust and ice called the Kuiper belt).
Details can be found on the IAU's excellent question and answer page. But I'll summarize the questions I had.
1. So what's a planet?
To be a planet, an object must satisfy two criteria. First, the object has to orbit a star. Second, it has to be massive enough such that it's mostly spherical. (Size and shape are related. If an object has a mass above 5 x 10^20 kg and diameter greater than 800 km, its own gravity will tend to form it into a spherical shape in time. This is really pretty small if you think about it. 800 km is about 500 miles. Pluto, the currently-accepted smallest planet, has a diameter of about 2300 km.)
2. There were nine. Now twelve? What the...? Where did the extras come from?
I personally thought this was mainly about whether Pluto and 2003 UB313 were going to stay, or get into, the planetary club. But the IAU proposal makes a point of not only letting them in, but further recognizing Charon and the largest asteroid, Ceres. Not only that, but if the proposal gets approved, there are twelve more candidates for planethood (other plutons and asteroids), pending further observations and refinement of the definition. And there will undoubtedly be other Kuiper belt objects found that will enter the planetary debate.
3. Where do they get off counting Charon? Isn't it a moon?
The IAU considers Pluto and Charon a different breed altogether, calling them a "double planet" instead of a planet and satellite, because the center of mass of the system (the "barycenter") is above Pluto's surface (i.e., in the space between the two). All moons orbit planets around the center of mass, but for the Earth's Moon and other large satellites around the outer planets, the barycenter is well below the planet's surface. (I won't get into a big physics discussion about orbits and barycenters now, but have a look at the wikipedia definition here for an explanation and nice animations of the concept.)
Posted by jkwilson ( Aug 16 2006, 09:55:34 AM EDT ) Permalink Comments [2]
Wednesday August 02, 2006
Powers of observation
A quick science test from Richard Muller's terrific book Nemesis (which I'll discuss more soon):
***
He pulled out the large, red-bound Snowbird Conference Proceedings. In it was a map of the eighty-eight known impact craters on the Earth. "You'll notice that most of them are in Europe and North America. Can you guess why?"
I thought of rotations of the Earth, but had no luck in figuring out why impacts would be more likely in the Northern Hemisphere. Walt didn't let me waste time for long. He said, "Because that is where the most geologists live."
***
Posted by jkwilson ( Aug 02 2006, 04:59:20 PM EDT ) Permalink Comments [1]
Thursday July 27, 2006
Science is a trail of learning, littered with carcasses of failure
From Modern Mechanix (endlessly entertaining scans of old magazines), here's a theory that didn't quite have the legs:
(Transcription available at http://blog.modernmechanix.com/2006/07/26/light-gets-tired-and-turns-red/ )
Yeah, that's a nice little anthropomorphic theory, but no, light doesn't get tired. For an overview of what actually causes redshift, have a look here."I just flew in from the origin of the universe, and...!" ...nevermind.
Posted by jkwilson ( Jul 27 2006, 10:02:24 AM EDT ) Permalink
Tuesday July 25, 2006
Albert Einstein disproves the existence of Vulcan
Nowadays debate about the number of planets in
our solar system revolves around arguing about exactly which of the
slightly-larger-than-average icy bodies should be included in the count.
Also, if you talk about the planet Vulcan, it is assumed you are simply a
harmless Star Trek nerd referring to the homeworld of a fictional race of
emotionless humanoids.
Consider a time when neither of those things were true. Consider the 19th
century.
In the 1840s, French astronomer Urbain Jean Joseph Le Verrier began applying
Newtonian dynamics to the problems of planetary orbits. After noticing a
discrepancy between his calculations and the direct observations of Uranus, he
predicted that Uranus was being gravitationally affected by another more
distant planet. He was even able to predict where it was in its orbit
before it was observed. In 1846, Neptune was discovered where foreseen,
lending credence to both Le Verrier and Newton.
In the 1850s, feeling emboldened by his historic prediction, Le Verrier turned
his sights on the other planets. Similar to the perturbations he noticed
in Uranus's orbit, he also found problems with Mercury, the innermost planet in
the solar system. He concluded that there must be another planet even
closer to the sun disturbing Mercury's orbit. He named it Vulcan (after
the Roman God of Fire).
I won't draw it out here. For decades he and others searched for Vulcan
without success. Le Verrier and other astronomers who supported the
Vulcan theory died convinced it would be found.
So what happened? Le Verrier had applied Newtons's laws correctly.
If the theory is correct, the outcome must be predictable, yet the prediction
in this case ultimately failed. Had Newton been wrong about gravitational
laws?
Nah. It just didn't account for everything. Turns out the
inconsistencies between observation and prediction were actually a relativistic
effect:
The advance of Mercury's perihelion was
brilliantly explained by Albert Einstein in November 1915 at his desk in Berlin
-- his general theory of relativity finally exorcised the ghost of Vulcan from the inner solar system. Einstein
presented a new theory of gravitation that conceived of it as a warping of the
fabric of space-time. According to his theory, Mercury should precess slightly
faster than the Newtonian rate -- by 0.1 arcseconds for each orbital revolution
of the planet, or 43 arc-seconds per century. This agreed exactly with the
observed rate. Vulcan became redundant.*
Unfortunately Le Verrier
didn't know about relativity, and spent a good portion of his professional life
trying to work on a problem that demanded its contributions.
*Excerpted from "Vulcan
Chasers" by William Sheehan and Richard Baum, Astronomy, volume 25, issue 12 (December 1997).
Read more of the story there, or the wikipedia article here.
