31 October 2005

American Astronomical Society: Statement on the Teaching of Evolution

The American Astronomical Society (AAS, pronounced "double-A-S") released a statement Sept 20, 2005 on the teaching of evolution. Quoted below in its entirety, follow the link above for a list of further reading.

The American Astronomical Society supports teaching evolution in our nation’s K-12 science classes. Evolution is a valid scientific theory for the origin of species that has been repeatedly tested and verified through observation, formulation of testable statements to explain those observations, and controlled experiments or additional observations to find out whether these ideas are right or wrong. A scientific theory is not speculation or a guess -- scientific theories are unifying concepts that explain the physical universe.

Astronomical observations show that the Universe is many billions of years old (see the AAS publication, An Ancient Universe, cited below), that nuclear reactions in stars have produced the chemical elements over time, and recent observations show that gravity has led to the formation of many planets in our Galaxy. The early history of the solar system is being explored by astronomical observation and by direct visits to solar system objects. Fossils, radiological measurements, and changes in DNA trace the growth of the tree of life on Earth. The theory of evolution, like the theories of gravity, plate tectonics, and Big Bang cosmology, explains, unifies, and predicts natural phenomena. Scientific theories provide a proven framework for improving our understanding of the world.

In recent years, advocates of “Intelligent Design,” have proposed teaching “Intelligent Design” as a valid alternative theory for the history of life. Although scientists have vigorous discussions on interpretations for some aspects of evolution, there is widespread agreement on the power of natural selection to shape the emergence of new species. Even if there were no such agreement, “Intelligent Design” fails to meet the basic definition of a scientific idea: its proponents do not present testable hypotheses and do not provide evidence for their views that can be verified or duplicated by subsequent researchers.

Since “Intelligent Design” is not science, it does not belong in the science curriculum of the nation’s primary and secondary schools.

The AAS supports the positions taken by the National Academy of Sciences, the American Association for the Advancement of Science, the National Science Teachers’ Association, the American Geophysical Union, the American Chemical Society, and the American Association of Physics Teachers on the teaching of evolution. The AAS also supports the National Science Education Standards: they emphasize the importance of scientific methods as well as articulating well-established scientific theories.


30 October 2005


Reading about how the "Pluto Express" mission is being delayed by hurricane damage prompts me to discuss Pluto.

Pluto is not a planet.
Hear me out, I'll explain why!

Merriam-Webster has this to say about planets.

1 a : any of the seven celestial bodies sun, moon, Venus, Jupiter, Mars, Mercury, and Saturn that in ancient belief have motions of their own among the fixed stars b (1) : any of the large bodies that revolve around the sun in the solar system (2) : a similar body associated with another star c : EARTH -- usually used with the
2 : a celestial body held to influence the fate of human beings
3 : a person or thing of great importance : LUMINARY

Interestingly, they don't even specify the 9 generally accepted planets! Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto - My Very Excellent Mother Just Served Us Nine Pizzas. Mercury Venus Earth Mars (Asteroids) Jupiter Saturn Uranus Neptune Pluto - Most Voters Earn Money (Always) Just Showing Up Near Polls.

Dictionaries start off with the oldest definition, which here is objects that appear to move throughout the sky, hence the Greek name of "wanderer." The ancient Greeks could observe through Saturn with the naked eye. You can too, even in a city. Even if you don't know where to look, if you occasionally see a "star" that's especially bright, see it before the stars come out, more colored than the others, and doesn't seem to twinkle as much, and doesn't move, that's probably a planet.

Then in the 1800's telescopes helped astronomers realize that there were a couple other things wandering through the sky - Uranus and Neptune. Calculations of irregularities in Mercury's briefly made people think there might be a planet inside its' orbit, named Vulcan, but a test of Einstein's general relativity circa 1913 proved (with large margins of error) that GR could do it alone. Calculations of irregularities in Neptune's orbit (by Percival Lowell) led to the discovery of Pluto (by Clyde Tombaugh), but only because the two errors in the calculations happened to cancel out and Pluto was in just the right spot.

Somewhen in there asteroids were discovered - the first of them, Ceres in 1801, was briefly considered a planet until we realized there were lots of them orbiting at roughly the same distance from the sun. Then in the 1990's, Geoff Marcy and various others started discovering planets in other solar systems (we've topped 100). From 1992 through to the present day this was topped by Mike Brown (and others') discovery of three Pluto-sized objects further out than Pluto: Sedna, Quaoar, and 2003_UB313 (aka Xena). These objects are variously called trans-Neptunian objects (things that sometimes orbit w/in Neptune's orbit, as does Pluto), Kuiper Belt Objects (aka KBOs, like another asteroid belt but outside Neptune's orbit), and some call them more planets. Do we really want to add more planets? One is larger than Pluto; if it's not a planet, then is Pluto? If there's lots of them, like another asteroid belt, shouldn't we drop Pluto like we did Ceres? But we've been calling it a planet for so long, we shouldn't drop it now.

This all begs the question:
What is a planet?

Unfortunately, astronomers haven't ever officially declared a definition of a planet, so we're left with a conundrum. There's an assortment of characteristics that seem to be generally agreed upon, but not universally.

  1. Orbits the sun (or star, or primary star, or pair of stars). In our solar system this includes a shit load of things. This includes asteroids, comets, planets, but not moons.

  2. Small enough to not be undergoing nuclear fusion. There is a class of objects known as brown dwarfs, nicknamed "failed stars," that are larger than Jupiter but too small to be stars. They typically have tiny amounts of fusion (of deuterium, for example), but are considered somewhere between stars and planets. This isn't an issue in our Solar System (Jupiter is 100x too small to be a brown dwarf), but it's important in other systems.

  3. Large enough to be round from self-gravitation. Moons included, but not asteroids and comets.

  4. Only thing in its orbit. Excludes planets with moons, excludes planets that have asteroids trailing or leading in the same orbit (such as Earth and Jupiter).

    Largest or dominating body in its or a similar orbit. Somewhat vague, excludes moons, but not clear when multiple bodies the same size. Some have suggested that "dominates its orbit" be clarified as "the body's mass must be greater than the masses of all objects in similar orbits." It would exclude asteroids, comets, and KBOs (such as Pluto).

The five definitions above are generally accepted, but not officially accepted. The International Astronomical Union (IAU) is the governing astronomy body that keeps track of objects, and they've had a "working group" that Wikipedia claims will announce a definition by the end of the year. I personally hope that rather than just handing it down from on high, that they allow a period of public commentary from both the astronomical community and the general public. It seems like such an interesting topic with so many differing opinions that it would be a good thing to get more general input. Additionally, if it's controversial, publicizing things in that way would help stir up more public interest in astronomy. *grin*

28 October 2005

Gravity in space

This is an old one I started a while ago but didn't finish...

China's Shenzhou VI spacecraft is not orbiting exactly as planned and will have to be restored to its original trajectory, state-run media say.
The "orbit maintenance operation" would take place early on Friday morning, said official news agency Xinhua.

Gravity has drawn Shenzhou VI too close to earth, the agency said.

Shenzhou VI, which has two astronauts on board, is in a low enough orbit to be affected by the Earth's gravitational pull.


Gravity acts over infinite distance. It does get weaker as you get further from something, but it never goes away entirely. For the geeks, the formula is F=GMm/r^2, where F is the force of gravity, G is the gravitational constant, M and m are the masses of two objects (typicall M is the bigger, like Earth, and m is the smaller, like Shenzhou VI), and r is the distance between the two. Note that as r gets bigger and bigger, F gets smaller and smaller, but you can never get to F=0.

Astronauts in the International Space Station, or onboard a Space Shuttle aren't floating because there's "no gravity," they're actually falling towards the Earth as fast as they're going around it. Think of it like if you're in an elevator and the cable was cut. As both you and the elevator fall, you're "floating" inside the box, but gravity is DEFINITELY pulling you. This state is called free fall.

As for Shenzhou VI, they probably meant either it wasn't in a stable orbit to start, or else the tenuous bits of atmosphere are causing some friction which slows it down and decays the orbit.

Science standards copyrighted - who would've thunk!

<rant alert>
The National Academy of Sciences (NAS) and the National Science Teachers Association (NSTA) has told the Kansas DOE that as long as they put ID into their state standards, they are not allowed to base their state standards off of their national versions. That is, the NAS/NSTA are invoking their copyright. Reply from Bruce Chapman, president of the Discovery Institute (an ID-supporting Seattle, WA group), said of the NAS/NSTA, "They've set themselves up to be the arbiter when in fact they're partisan. That's obvious now, or it should be."

No shit sherlock. Their job is to say what's science, just like a bishop gets to decide what's taught in Sunday school. Wouldn't you be pissed off if a science teacher walked into your church and started preaching evolution and praising the word of Darwin? If you want us to keep our science out of your religion, then keep your religion the fuck out of our science.

24 October 2005

Global Warming

The topic of global warming is a hot one - har har! No seriously, every industrialized country thinks it's a big deal, except the US. Global warming is defined as a worldwide trend for warmer temperatures on average - it is also known as climate change, as it's important to distinguish that it is a large scale thing (as climates are), and not a small scale thing (as weather is). The term "climate change" is also less politically loaded here in the States than "global warming." There are a few important questions that must be answered to fully understand global warming.

  1. Is it happening?

  2. If so, what is causing it?

  3. Can human activity be causing it?

  4. Whether or not humans cause it, could we stop or reverse it?

  5. If we can, should we?

1. Is global warming happening?
YES. The only person who could possibly deny this part is the great Dubya himself. Well, and a few woo-hoos who also believe that the Apollo program was faked.

The actual evidence is very strong. We have direct thermometer measurements of the temperature since the mid-1800's, and the average temperature has increased by a full Celsius degree since then.

Global Temperatures 1855 - 2003

Prior to then we need to use indirect methods of calculating the temperature or climate. The most interesting (and least believable) one I've seen is a study of the backgrounds in historical paintings. During what was known as the Little Ice Age, paintings showed more clouds than they did before and after. Like I said, I'm skeptical of it. A better method is tree rings: the thickness of a tree ring indicates how good the growing season was for the tree, and this includes information such as the rainfall and temperature. That only goes back as far as the oldest tree we've cut down, so longer ago than that we need to measure ice core samples - the thickness of ice that's been laid down in glaciers over the last millenia. Graphs of these data show that prior to the 1800's the Earths' temperature was relatively flat. In other words, the temperature has jumped since the 1800's. Global warming IS happening.

2. What is causing global warming?
Probably a runaway greenhouse effect, or maybe increased input of energy (i.e. solar output).

In moderation, the greenhouse effect is a good thing. Without it, we'd be as cold and lifeless as Mars. In an actual greenhouse, light and heat from the sun pass in through the glass, but not all of it makes it back out through the glass. The excess light and heat reflect around inside the greenhouse and heat it up. Eventually the temperature does stabilize at a higher temperature than the outside air.

On the Earth, it's the atmosphere that keeps the heat and light in. You have witnessed this yourself - the easy one to visualize is how on clear winter nights it's colder than on cloudy winter nights. This is because the clouds help trap more heat than the clear air. Same reason why deserts are frigid at night. An everyday example though, is "Why is the sky blue?" Because of the light from the sun that gets scattered in all directions. The blue in the sun's light gets scattered more than the red, so the blue looks like it's coming from all over, while at sunset the blue goes away from the direction of the sun leaving it looking red.

What makes the process "runaway" is when too much heat and light gets trapped. Specifically, we know that chemicals such as carbon dioxide (CO2) are good greenhouse gasses. Like historical temperatures, we have historical records of carbon dioxide only for the past 50 years or so. Those show CO_2 increasing, which seems to confirm the hypothesis that it causes global warming. Another piece of evidence is, well, can you think of something important that happened in the mid-1800's? The industrial revolution and steam power (which releases CO_2). That led to cars (1910's) and even more CO_2. In fact, we can today measure how much CO_2 the world creates, and it matches reasonably well with how much we observe in the air. It is currently the leading theory of the cause of global warming.

However, if you've been reading this blog a while you know that scientists can never be 100% sure of anything. A competing hypothesis is that the sun has been getting brighter. If there's more light coming into the greenhouse, of course it'll get hotter. Again, we only have limited data, which so far is inconclusive, so it is unfalsifiable with current data.

3. Can human activity be causing it?
Yeah. Ditto above. There's evidence pointing that way, but it's "only" a theory.

I Drew This: Consensus

4. Whether or not humans cause it, could we stop or reverse it?
Yeah again. We know that CO_2 at the very least adds to the greenhouse effect and global warming, so if we reduce CO_2 emissions as per the Kyoto Protocol, we'd help to reduce global warming.

5. Regardless of whether humans caused global warming, if we can stop it, should we?
Probably. Regardless of whether a kid knocked out your window with a baseball or a tree fell on your house, should you replace the window? Probably.

If global warming's a Bad Thing, it doesn't matter where the blame lies, we need to fix it. And yeah, for the most part it IS a Bad Thing: we're losing whole islands in the South Pacific, whole glaciers and the ecosystems they support, and even the winter sports industry is being hurt. :-P

On the other hand, there's probably a few PETA members out there who say "if it's natural, it's not our place to interfere." While I can understand that point of view, I'm not sure I agree. If a killer asteroid were heading towards the Earth, I'd sure as heck wanna find a way to stop it and save us.

21 October 2005

European mission to Venus delayed

To be launched by a Soyuz rocket in a few days and begin orbitting Venus in a year, here's hoping the Venus Express does better than the recent Cryosat launch. That one was also launched by the Russians (the European Space Agency does not have launch capability, only the US, Russia, and China do as far as I know), but via a modified ICBM. I guess they didn't modify it enough, but at least it didn't have the warhead still installed...

The loss of Cryosat was a real disappointment to me, as its primary purpose was to monitor the thickness of polar ice sheets, and thus provide more evidence for global warming, which us stupid backwater Americans are still denying.

Oh, and fascinatingly, a Google search on "ESA polar ice satellite" yields an Aljazeera page as its first hit.

Human stem cell brain injection approved by FDA

The FDA has approved a procedure to be done at Stanford University involving stem cells. The stem cells are harvested by a private group from aborted fetuses. "Immature neural cells" (brain stem cells) are yoinked out of the dead not-quite-humans and injected into the brains of children sufferring from Batten disease.

Batten disease is caused by a defective gene that fails to create an enzyme needed in the brain to help dispose of brain cellular waste. The waste piles up and kills healthy cells until the patient dies. Most victims die before they reach their teens.


The kids being experimented on WILL DIE within years without the experiment. They'll probably die anyway, but maybe more slowly. The injected neurons take over the kid's brain and make it work right.

Next step, increased usage of the death penalty with compulsory organ donation!

19 October 2005

Astrology and ID both scientific, claims Pennsylvania prof

A trial facing the US courts is over whether K-12 teachers in Dover, PA, should read a statement to their students questioning Darwinian evolution before teaching the content. Eleven parents are sueing the school board saying that the statment is tantamount to promoting religious creationism, while the school board claims that they are only making the students aware of the controversy in an unestablished claim. In the quote below, Rothschild is the attourney for the plaintiffs (the 11 pro-evolution parents), while Behe is a witness for the defense (pro-intelligent design school board). Behe is a biochem prof at University, Bethlehem, PA.

Rothschild told the court that the US National Academy of Sciences supplies a definition for what constitutes a scientific theory: “Theory: In science, a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.”

Because ID has been rejected by virtually every scientist and science organisation, and has never once passed the muster of a peer-reviewed journal paper, Behe admitted that the controversial theory would not be included in the NAS definition. “I can’t point to an external community that would agree that this was well substantiated,” he said.

Behe said he had come up with his own “broader” definition of a theory, claiming that this more accurately describes the way theories are actually used by scientists. “The word is used a lot more loosely than the NAS defined it,” he says.

Hypothesis or theory?

Rothschild suggested that Behe’s definition was so loose that astrology would come under this definition as well. He also pointed out that Behe’s definition of theory was almost identical to the NAS’s definition of a hypothesis. Behe agreed with both assertions.

The exchange prompted laughter from the court, which was packed with local members of the public and the school board.

Behe maintains that ID is science: “Under my definition, scientific theory is a proposed explanation which points to physical data and logical inferences.”

“You've got to admire the guy. It’s Daniel in the lion’s den,” says Robert Slade, a local retiree who has been attending the trial because he is interested in science. "But I can’t believe he teaches a college biology class."

(New Scientist)

See also my post on science words.

What's wrong with Astrology

Have you noticed that when you click on people's blogger profiles, it lists their astrological sign?

There are numerous things wrong with astrology.

  • At its vaguest, it is unfalsifiable by making general statements that can apply to anyone. (I.e., this aspect is unfalsifiable.)

  • At its most precise, it should have been able to predict the discovery of planets such as Neptune, Uranus, Pluto, and maybe even asteroids (Ceres) and Kuiper Belt Objects (Quaoar, Sedna, Xena/2003UB13). Astrologers failed to do so, and therefore have failed the one objective test that we could administer. (I.e., this aspect has been falsified.)

  • Precession - a wobbling effect of the Earth's axis - means that you weren't actually born in your birth sign, but the one after. The "first point in Aries" (vernal equinox, first day of Spring) actually is in Pisces, and it's nearly the "Age of Aquarius."

  • They left out Ophiuchus. There's actually 13 zodiacal constellations, and it's the extra.

Now that you've listened to me rant about it, listen to someone else rant, and then try very hard not to mock ID proponents.

16 October 2005

Brits asked to count frogs for science

Worldwide one-third of frog species are facing extinction from two diseases, one viral and one fungal. This is of course in addition to their sensitivity to pollution, climate change, and destruction of its natural habitat. If you live in Britain, you can help with the effort to track frogs and determine whether they're sick by visting the website Froglife and filling out and mailing a 14-question survey. Not that bad a task to help protect frogs worldwide. One thousand responses are needed to adequately sample British frogs.

14 October 2005

HST repair?

This one's a request for info if any of you know, rather than an explanation.

Formerly, NASA had said the minimum number of shuttle flights needed to construct the orbiting station was 28; now, that number has been reduced to 18, plus another flight to repair the aging Hubble Space Telescope.


Has anyone heard anything, or is this a typo or new thing? The AAS (American Astromical Society) doesn't say anything, and if anyone would know, they would.

13 October 2005

Biological basis for lying

A USC study has found the first proof of structural brain abnormalities in people who habitually lie, cheat and manipulate others.
The subjects were taken from a sample of 108 volunteers pulled from Los Angeles’ temporary employment pool. A series of psychological tests and interviews placed 12 in the category of people who had a history of repeated lying (11 men, one woman); 16 who exhibited signs of antisocial personality disorder but not pathological lying (15 men, one woman); and 21 who were normal controls (15 men, six women).
After they were categorized, the researchers used Magnetic Resonance Imaging to explore structural brain differences between the groups. The liars had significantly more “white matter” and slightly less “gray matter” than those they were measured against, Raine said.
[Yaling] Yang, the study’s lead author, said the findings eventually could be used in making clinical diagnoses and may have applications in the criminal justice system and the business world.

“If [the findings] can be replicated and extended, they may have long-term implications in a number of areas,” said Yang, a doctoral student in the USC department of psychology’s brain and cognitive science program.

“For example, in the legal system they could potentially be used to help police work out which suspects are lying. In terms of clinical practice, they could help clinicians diagnose who is malingering – making up disability for financial gain.

“And also in business, they could assist in pre-employment screening, working out which individuals may not be suitable for hiring.

(University of Southern California)

I find this worrisome - how is this any different from profiling?

11 October 2005

Controversy in Human Evolution

This one really IS a controversy. On the Indonesian island Flores, inside a cave, bones from a number of humans from some 12,000 to 95,000 years ago have been found. "Human" here is a broad term including neanderthals down to modern homo sapiens sapiens. These particular bones are significantly smaller than those of other homo sapiens of the same time, and most archaeologists/biologists believe they're of a new species and call them homo floriensis, familiarly known as Hobbits. A number of scientists remain unconvinced; they point out that these could've been an isolated group of dwarf homo sapiens. Only time will tell which hypothesis will win out and become the accepted theory.

UPDATE: See this article for more details on the controversy.

08 October 2005

Untestable Hypothesis and Falsifiability

The Scientific Method has some five key steps to it, as mentioned previously, and reminded here.

  1. Observation/Question

  2. Hypothesis

  3. Prediction

  4. Experiment

  5. Conclusion

One of the toughest parts of the Scientific Method is simply determining whether it's possible to design an experiment to test your hypothesis. If it IS possible to test it, and there are clear conditions for what counts as refuting your hypothesis, the hypothesis is called falsifiable, and this is a good thing in science. "Falsifiable" means the same thing as "testable," it doesn't mean "proven false." Yeah, it's confusing. So some examples may help.

Hypothesis: There are NO black swans.
Test: Look for a black swan.
Falsifiable? Yes
Potential Falsification: Finding a black swan.
Truth Status: False (there are black swans).

Hypothesis: There are pink elephants.
Test: Look for a pink elephant.
Falsifiable? No
Potential Falsification: None. If you looked around the whole world, maybe it was hiding in Japan while you were in New Zealand. If you saw the whole world simultaneously, maybe it's on Mars. Or another solar system. It's impossible to actually carry out the test.
Truth Status: So far it appears false, but we're not sure. The statment "there is no such thing as a pink elephant" is a good example of something that a non-scientist would call a fact but scientists would say is unproven.

Hypothesis: Throwing a virgin in an active volcano appeases the gods and prevents the volcano from erupting.
Test: Don't throw a virgin in volcanos.
Falsifiable? Partially.
Potential Falsification: The problem is that if you do throw in the virgins and it doesn't erupt, you're not sure if it's that or something else which prevented the volcano from erupting. If you don't throw in virgins and it does erupt, you're not sure if it's that or something else which did make it erupt. The only condition which definitely would falsify it would be if we threw in a virgin and the volcano erupted anyway. Another way to think about it is that we can't test supernatural forces.
Truth Status: Essentially false, as we've got other explanations for volcano eruption that do not evoke supernatural forces.

Hypothesis: Waging war in Iraq keeps America safe.
Test: Don't wage war in Iraq and see if we get "less safe."
Falsifiable? Perhaps, but are we willing to try the test? And how would we quantify it?

Responding to the president's [Oct 6 (?), 2005] address , the Senate Minority Whip, Dick Durbin, D- Illinois, said the speech left too many questions about the Iraq war unanswered.

"He owes it to the American people -- and the Democrats are calling on him to tell the American people -- how will this end? How can we measure success? How can we get beyond the generalities of the speech that we heard today?" Durbin said.


02 October 2005

NASA's Chewbacca

Today I heard of a logical fallacy that Wikipedia refers to as the Chewbacca Defense, as per a South Park reference. This is an argument that attempts to convince by confusion, see also the red herring fallacy.

The example that prompted me to blog about it is that NASA has been accused of misspending money by using its own planes to fly its employees around the country, rather than buying cheaper airline tickets. Said Sen. Susan Collins, R-Maine,

"In the environment we're in right now with tight federal budgets and the demands of responding to Hurricane Katrina, it is particularly disturbing to learn that a federal agency is not being a more careful steward of the taxpayers' dollars. There's also a waste of fuel here, too."


Um, someone explain to her that while everyone's sad about Katrinia, and yeah gas prices suck, it doesn't make NASA any more guilty of things they've done for the past 15 years. Next thing you know, in addition to reductio ad Hitlerum and reductio ad terrorism arguments being common, you'll have reductio ad Katrina arguments.

Virus and Bacteria Evolution

The clearest and most current example of evolution that I can think of is the modern-day mutation of viral and bacterial strains. Antibacterial resistant strains of bacteria are cropping up in hospitals across the industrialized world, where we overuse antibacterial washes and such. The chemicals kill most of the bacteria on your hands, but a few hardy ones manage to survive. They pass on their hardy traits to make a new population of hardier (resistant) bacteria.

The avian flu (H5N1) rampant in Asia is another example. On the one hand, some strains of it are mutating to become resistant, which means they will come to dominate their weaker peers. And on the other hand authorities worry that a strain transmissible from human to human will develop. This would be devastating to humankind, as 150 million could die (around 2.3% of the 6.5 billion in the world), and of course it'd start with third world countries, and make it to poor people in first world countries (though America's politicians would be safe).

An optimally evolved human disease would be one that could live in its host for years, and spread quickly and easily before its host died or was cured. Common cold spreads easily, but we fight it off to quickly. HIV can't be gotten our of our systems, but it takes too much to spreads it. There's a large number of bacteria commonly found on the skin that I think fit the bill the best, as they live happily on our skin and most people don't know about it at all. Things like staph, and the stuff that causes ringworm and athlete's foot. Those're there all the time. Yum.


I have been searching for a word for years, and I have finally found it! The word is antumbra, I found it thru a BBC article, and it means that part of the moon's (or another body's) shadow where an annular eclipse of the sun (or other light source) can be viewed. I'd already known the words umbra (for where you can see a total eclipse) and penumbra (partial), and I always suspected that there must be a special name for that section of the penumbra where you got a "reverse umbra," and finally I have found the word!

Oh yeah, it's taking place Monday Oct 2 for those of you in Europe, the "Near East" and Africa.