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.
(AAS)
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.
30 October 2005
Pluto
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.
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.
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*
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.
- 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.
- 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.
- Large enough to be round from self-gravitation. Moons included, but not asteroids and comets.
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...
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.
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.
(BBC)
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.
</rant>
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.
</rant>
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 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.
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.
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.
- Is it happening?
- If so, what is causing it?
- Can human activity be causing it?
- Whether or not humans cause it, could we stop or reverse it?
- 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.
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.
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.
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.
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!
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.
(CNN)
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!
Subscribe to:
Posts (Atom)
