Just read The Tyranny of E-mail: The Four-Thousand-Year Journey to Your Inbox by John Freeman (Scribner, 2009).
I have to say I wasn't overly impressed. While I agree with much of what the author writes, I found the book simplistic and many of the points made are obvious (at least to someone who used email before most people had ever heard of it). This book could have been written (much shorter) as an article in a magazine.
After initial observations on the explosive growth of email, Freeman launches into a rather superficial history of communication from clay tablets to early mail to the growth of the modern postal system. He discusses the lost art of letter writing and the picture postcard craze of the 19th and 20th centuries. Telegraphs and typewriters lead into an introduction of the origin and growth of the Internet and email.
Quite honestly, I've read deeper, less superficial, discussions of these topics on Wikipedia.
The book wraps up with lots of anecdotes (and no references to actual studies) of how some people are apparently addicted to email and how computers and electronic gadgets take up more and more of our lives. As someone who's a heavy user of computers, maybe I have a problem too, but I would remind people that I'm sitting here writing this in my living room on a weeknight at 8:30 pm with the television turned off. I think many more people are addicted to television than computers or email.
While I do know people who are addicted to their "Crackberries" checking work email on Friday evenings during happy hour in the bar, I also know plenty of other people who set limits on when and where they'll check their email (especially important as a professor - students will sometimes email you at 2 am on a Saturday night and get annoyed you don't answer until 9 am Monday morning!).
Bottom line, summarizing the entire book, is we all need to slow down and not let email and the Internet take over our lives. There, I just saved you a few hours of reading - go out and smell the roses with that saved time (or check your inbox - whatever).
Thursday, September 30, 2010
Wednesday, September 29, 2010
We're # 48 rah rah!
What more can I say? Fucking pathetic.
Another gem from the article: 49% of U.S. adults don't know how long it takes for the Earth to circle the sun.
I don' need nun
yur fancy book-larnin'
Tuesday, September 28, 2010
Fibonacci rectangles and spirals
Make sure you read my Introduction to Fibonacci Numbers post before you read this...
Follow along with the diagram below.
Take a square with a side of 1 unit.
Add another square to the side (1 unit) of the original square. Now you have a 2 x 1 rectangle.
Add another square to the larger (2 unit) side of this rectangle. Now you have a 3 x 2 rectangle.
Add another square to the larger (3 unit) side of this rectangle. Now you have a 5 x 3 rectangle.
Add another square to the larger (5 unit) side of this rectangle. Now you have an 8 x 5 rectangle.
Add another square to the larger (8 unit) side of this rectangle. Now you have a 13 x 8 rectangle.
As you can see, you can continue this indefinitely. You've probably already noticed that the sides of the rectangles are succesive numbers from the Fibonacci sequence (1, 1, 2, 3, 5, 8, and 13 but future additions would yield 21, 34, 55, 89, etc.)
In my last post introducing the Fibonacci numbers, I mentioned that dividing successive Fibonacci numbers (Fn / Fn-1) approaches a constant (the higher the Fibonacci numbers, the more decimal place accuracy obtained for this constant). The constant is called Phi (F). The ratio of the two sides of these larger and larger rectangles similarly approach F which is why they are called Fibonacci rectangles.
Now, let's get interesting. For each square that you've added, draw a 1/4 circular arc from corner to corner with the radius of the arc equal to the side of the square. Continue in a clockwise direction from square to square and you'll find yourself drawing a nice spiral (here's an animation).
This is called a Fibonacci spiral for obvious reasons (technically, it approximates a Fibonacci spiral since these rectangle ratios approximate F). There are objects in nature that look very much like Fibonacci spirals such as the chambered nautilus (Nautilus pompilius) shown below (sawn in half).
Here's a nice spiral galaxy (M74).
We see these types of curves in nature when an object's growth is proportional to its size.
Follow along with the diagram below.
Take a square with a side of 1 unit.
Add another square to the side (1 unit) of the original square. Now you have a 2 x 1 rectangle.
Add another square to the larger (2 unit) side of this rectangle. Now you have a 3 x 2 rectangle.
Add another square to the larger (3 unit) side of this rectangle. Now you have a 5 x 3 rectangle.
Add another square to the larger (5 unit) side of this rectangle. Now you have an 8 x 5 rectangle.
Add another square to the larger (8 unit) side of this rectangle. Now you have a 13 x 8 rectangle.
As you can see, you can continue this indefinitely. You've probably already noticed that the sides of the rectangles are succesive numbers from the Fibonacci sequence (1, 1, 2, 3, 5, 8, and 13 but future additions would yield 21, 34, 55, 89, etc.)
In my last post introducing the Fibonacci numbers, I mentioned that dividing successive Fibonacci numbers (Fn / Fn-1) approaches a constant (the higher the Fibonacci numbers, the more decimal place accuracy obtained for this constant). The constant is called Phi (F). The ratio of the two sides of these larger and larger rectangles similarly approach F which is why they are called Fibonacci rectangles.
Now, let's get interesting. For each square that you've added, draw a 1/4 circular arc from corner to corner with the radius of the arc equal to the side of the square. Continue in a clockwise direction from square to square and you'll find yourself drawing a nice spiral (here's an animation).
This is called a Fibonacci spiral for obvious reasons (technically, it approximates a Fibonacci spiral since these rectangle ratios approximate F). There are objects in nature that look very much like Fibonacci spirals such as the chambered nautilus (Nautilus pompilius) shown below (sawn in half).
We see these types of curves in nature when an object's growth is proportional to its size.
Monday, September 27, 2010
I love this!
It's a parody of how science journalism works:
This is a news website article about a scientific paper
I love it! About as much as I despise most of what passes for science journalism in the mass media.
This is a news website article about a scientific paper
I love it! About as much as I despise most of what passes for science journalism in the mass media.
Introduction to Fibonacci numbers
I plan on writing a few posts about Fibonacci numbers over the next few days simply because I think they're neat and interesting.
Fibonacci numbers are named after Leonardo of Pisa (c. 1170 - c. 1250), later known as Fibonacci (an name attributed to him from the contraction of filius Bonacci or "son of Bonaccio").
Fibonacci was one of the premier mathematicians of his day. His Italian merchant father was a diplomat staioned in Bugia in what's now Algeria in North Africa and Fibonacci was able to travel with him around the Mediterranean world.
In 1202, Fibonacci wrote Liber Abaci which means "Book of the Abacus" or "Book of Calculation." In it, he introduced the European world to the Hindu-Arabic number notation. This was a huge advance for western mathematics (try doing math with Roman numerals!).
European merchants quickly saw the advantage of the new Arabic numerals which greatly simplified bookkeeping chores. This new system of notation also led to advances in mathematics which suddenly became much easier with the improved notational system.
In Liber Abaci, Fibonacci proposed a hypothetical problem whose answer has intrigued people for almost a millennium now. It has to do with rabbits (you know the stereotype about rabbits, right?). Assume rabbits can mate at one month of age and at the end of the seconds month have a litter of two rabbits - one male and one female. Rabbits never die and each month, from the second month on, keep producing a new pair of male and female rabbits. Unrealistic, but it's a hypothetical problem, we're allowed to set whatever conditions we like.
So, let's start with a pair of bunnies. How many rabbits will there be at the end of each month? Check out the figure below. Pink and blue for female and male bunnies, lighter colors for sexually immature and darker colors for mature (takes 1 month to mature).
For the first month, we only have the original pair of immature bunnies. In the second month, the bunnies are now mature and hook up as nature intended. In the third month, the original pair has an offspring pair which are immature. In the fourth month, the original pair has another pair of offspring the the two mature pairs (original pair and first generation pair) have sex. In the fifth generation, the first pair has a second pair of offspring and the 1st generation pair has its own offspring. The two pair of offspring are immature.
And so on.
Note the progression in the number of pairs with each generation: 1, 1, 2, 3, and 5. If you continue this for a year, you'll see the sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, and 144. After one year, you'll have 144 pairs of bunnies. Looking at the sequence, it's obvious that each number is the sum of the two previous numbers (after we start with 1). This is called the Fibonacci sequence and its more formal definition is:
F1 = 1, F2 = 1, and Fn = Fn-1 + Fn-2
Using this notation F13 = 233 since F13-1 = F12 = 144 and F13-2 = F11 = 89 and 144 + 89 = 233.
Fibonacci numbers obviously form an infinite sequence because given any Fn, we can always generate Fn+1 from Fn + Fn-1.
Why is this so interesting? Who the hell cares about bunny sex besides rabbits? I'll post some interesting things about the sequence over the next few days but here's one thing...
The ratio of any two successive Fibonacci numbers (Fn / Fn-1) approaches a constant with successively larger pairs. For example:
F2 / F1 = 1/1 = 1.000000
F3 / F2 = 2/1 = 0.500000
F4 / F3 = 3/2 = 1.500000
F5 / F4 = 5/3 = 1.666667
F6 / F5 = 8/5 = 1.600000
F7 / F6 = 13/8 = 1.625000
...
F12/F11 = 144/89 = 1.617977528090
...
F24 / F23 = 28,657/17,711 = 1.618033990176
...
F48 / F47 = 4,807,526,976/2,971,215,073 = 1.618033988750
And so forth. The number approached is an irrational number (an infinite non-repeating decimal) designated by the Greek letter Phi (F). It's value (to 18 decimal places) is 1.618033988749894848… but realize it goes on forever and the higher you go in the Fibonacci sequence, the more closely you'll approach it.
This special number was called Phi (pronounced "fie" or "fee") after Phidias (Φειδίας) an ancient Greek artist who lived circa 480-430 BCE (his 12 meter high statue of Zeus at Olympia was one of the Seven Wonders of the Ancient World). The reason for this will wait until another post.
Fibonacci numbers are named after Leonardo of Pisa (c. 1170 - c. 1250), later known as Fibonacci (an name attributed to him from the contraction of filius Bonacci or "son of Bonaccio").
Fibonacci was one of the premier mathematicians of his day. His Italian merchant father was a diplomat staioned in Bugia in what's now Algeria in North Africa and Fibonacci was able to travel with him around the Mediterranean world.
In 1202, Fibonacci wrote Liber Abaci which means "Book of the Abacus" or "Book of Calculation." In it, he introduced the European world to the Hindu-Arabic number notation. This was a huge advance for western mathematics (try doing math with Roman numerals!).
When my father, who had been appointed by his country as public notary in the customs at Bugia acting for the Pisan merchants going there, was in charge, he summoned me to him while I was still a child, and having an eye to usefulness and future convenience, desired me to stay there and receive instruction in the school of accounting. There, when I had been introduced to the art of the Indians' nine symbols through remarkable teaching, knowledge of the art very soon pleased me above all else and I came to understand it, for whatever was studied by the art in Egypt, Syria, Greece, Sicily and Provence, in all its various forms.
European merchants quickly saw the advantage of the new Arabic numerals which greatly simplified bookkeeping chores. This new system of notation also led to advances in mathematics which suddenly became much easier with the improved notational system.
In Liber Abaci, Fibonacci proposed a hypothetical problem whose answer has intrigued people for almost a millennium now. It has to do with rabbits (you know the stereotype about rabbits, right?). Assume rabbits can mate at one month of age and at the end of the seconds month have a litter of two rabbits - one male and one female. Rabbits never die and each month, from the second month on, keep producing a new pair of male and female rabbits. Unrealistic, but it's a hypothetical problem, we're allowed to set whatever conditions we like.
So, let's start with a pair of bunnies. How many rabbits will there be at the end of each month? Check out the figure below. Pink and blue for female and male bunnies, lighter colors for sexually immature and darker colors for mature (takes 1 month to mature).
For the first month, we only have the original pair of immature bunnies. In the second month, the bunnies are now mature and hook up as nature intended. In the third month, the original pair has an offspring pair which are immature. In the fourth month, the original pair has another pair of offspring the the two mature pairs (original pair and first generation pair) have sex. In the fifth generation, the first pair has a second pair of offspring and the 1st generation pair has its own offspring. The two pair of offspring are immature.
And so on.
Note the progression in the number of pairs with each generation: 1, 1, 2, 3, and 5. If you continue this for a year, you'll see the sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, and 144. After one year, you'll have 144 pairs of bunnies. Looking at the sequence, it's obvious that each number is the sum of the two previous numbers (after we start with 1). This is called the Fibonacci sequence and its more formal definition is:
F1 = 1, F2 = 1, and Fn = Fn-1 + Fn-2
Using this notation F13 = 233 since F13-1 = F12 = 144 and F13-2 = F11 = 89 and 144 + 89 = 233.
Fibonacci numbers obviously form an infinite sequence because given any Fn, we can always generate Fn+1 from Fn + Fn-1.
Why is this so interesting? Who the hell cares about bunny sex besides rabbits? I'll post some interesting things about the sequence over the next few days but here's one thing...
The ratio of any two successive Fibonacci numbers (Fn / Fn-1) approaches a constant with successively larger pairs. For example:
F2 / F1 = 1/1 = 1.000000
F3 / F2 = 2/1 = 0.500000
F4 / F3 = 3/2 = 1.500000
F5 / F4 = 5/3 = 1.666667
F6 / F5 = 8/5 = 1.600000
F7 / F6 = 13/8 = 1.625000
...
F12/F11 = 144/89 = 1.617977528090
...
F24 / F23 = 28,657/17,711 = 1.618033990176
...
F48 / F47 = 4,807,526,976/2,971,215,073 = 1.618033988750
And so forth. The number approached is an irrational number (an infinite non-repeating decimal) designated by the Greek letter Phi (F). It's value (to 18 decimal places) is 1.618033988749894848… but realize it goes on forever and the higher you go in the Fibonacci sequence, the more closely you'll approach it.
This special number was called Phi (pronounced "fie" or "fee") after Phidias (Φειδίας) an ancient Greek artist who lived circa 480-430 BCE (his 12 meter high statue of Zeus at Olympia was one of the Seven Wonders of the Ancient World). The reason for this will wait until another post.
Sunday, September 26, 2010
Right Ascension & Declination
Before reading today's post, it would help to read yesterday's on latitude & longitude. Latitude and longitude fix the location of something on the surface of the Earth. The question we'll answer today is "How do astronomers specify the location of a star, or other celestial object, in the sky?"
Astronomers do this with something called the equatorial reference system which specifies the right ascension and declination of an object in the sky. This is closely analogous to longitude and latitude respectively but there are some important differences.
In order to understand this system, we have to first understand the concept of the celestial sphere. Imagine a large glass sphere around the Earth with stars painted on it (you can buy celestial globes which model this quite well – we have some in my Earth science lab). It's really the ancient view of the universe but it works well for our purposes.
Looking at the celestial globe above, you can see lines scribed on it that look like latitude and longitude lines. Those are the declination and right ascension lines. Declination, abbreviated with the Greek lowercase “d” or d, is analogous to latitude and right ascension, abbreviated with the Greek lowercase “a” or a, is analogous to longitude.
Now imagine extending the north and south poles of the Earth out to the celestial sphere. You’ve now defined the north and south celestial poles. Extend the Earth’s equator outward to define the celestial equator. With me so far?
Declination at the celestial equator is 0º, declination at the north celestial pole is +90º, and declination at the south celestial pole is -90º (N and S are not used in declination, only +/-). That's easy.
Right ascension, however, is a bit different. Because the Earth rotates once on its axis in 24 hours, there are 24 hour lines of right ascension (subdivided into minutes and seconds). This differs from longitude on Earth (which has 0-180º E and 0-180º W). The 24 hours of right ascension increase to the west (clockwise around the celestial globe as viewed from above its North Pole).
This time of year, a prominent star in the evening sky is Vega. Vega has a declination of +38º 47’ 37” (almost 39º north of the celestial equator). It has a right ascension of 18h 37m 18s (the abbreviations are hours, minutes, and seconds). It always has the same declination and right ascension, not matter what time of day or night or what location on Earth you’re viewing it from. In order to understand why that is, we have to complicate things a bit.
When looking at the celestial globe, imagine that the Earth is fixed and not moving. Then imagine the celestial sphere rotating around the Earth once every a day (there’s a complication here, it’s actually once every 23 hours and 56 minutes, not 24 hours, because the Earth is also going around the Sun as it rotates but don't worry about that here). So the star, and the declination/right ascension coordinate system ,are both rotating around the Earth (that’s why the star’s declination and right ascension are constant even though we see the stars moving through the sky during the course of the night - the coordinate system is moving too).
Now, just as with longitude on the Earth, there’s a problem when setting up right ascension. Where do you place the 00 hour line of right ascension? Once again, it’s arbitrary but a logical place was chosen. To understand, another complication must be discussed!
Look back at the celestial globe picture again. Notice how the north and south pole of the Earth are not oriented vertically but tilted. The amount of tilt is 23.5º from vertical. Why? Because the Earth’s axis is tilted by that amount. Tilted with respect to what? Tilted with respect to the Earth’s orbit around the Sun called the plane of the ecliptic. Imagine all of the planets in our solar system orbiting the Sun. They all orbit (roughly) in the same plane. From here on Earth, we see the Sun move across the sky between sunrise and sunset. The Sun is following the path of the ecliptic in the sky (on the Sun, we’d see the Earth following the path of the ecliptic in the sky – it goes both ways!). In the image below, all the planetary orbits define the plane of the ecliptic.
Back to the celestial globe. See the band of metal circling the celestial globe dividing it in half horizontally? That’s essentially where the ecliptic would be located. See the seam on the celestial globe halfway between the celestial poles? That’s the celestial equator. Note that the plane of the celestial equator and the plane of the ecliptic are at an angle from each other (a 23.5º angle). The band of the ecliptic and the band of the celestial equator intersect each other at two points. One of these points is defined as the 00 hour of right ascension. It actually corresponds physically to the spring or vernal equinox (the other intersection is the fall or autumnal equinox).
Examine the picture above. It shows the celestial sphere. The red line with the Sun on it is the ecliptic and the blue line is the celestial equator. Where they intersect is the vernal equinox. That’s the 00 hour line of right ascension.
Also note, in this figure, that right ascension hours increase to the right (counterclockwise when looking down from above the north celestial pole). Why? Because the celestial sphere is rotating around the Earth from east to west in a clockwise direction (imagine standing on the stationary Earth inside the celestial sphere, you’d see stars rising in the east and setting in the west just as you do in real life).
Astronomers do this with something called the equatorial reference system which specifies the right ascension and declination of an object in the sky. This is closely analogous to longitude and latitude respectively but there are some important differences.
In order to understand this system, we have to first understand the concept of the celestial sphere. Imagine a large glass sphere around the Earth with stars painted on it (you can buy celestial globes which model this quite well – we have some in my Earth science lab). It's really the ancient view of the universe but it works well for our purposes.
Looking at the celestial globe above, you can see lines scribed on it that look like latitude and longitude lines. Those are the declination and right ascension lines. Declination, abbreviated with the Greek lowercase “d” or d, is analogous to latitude and right ascension, abbreviated with the Greek lowercase “a” or a, is analogous to longitude.
Now imagine extending the north and south poles of the Earth out to the celestial sphere. You’ve now defined the north and south celestial poles. Extend the Earth’s equator outward to define the celestial equator. With me so far?
Declination at the celestial equator is 0º, declination at the north celestial pole is +90º, and declination at the south celestial pole is -90º (N and S are not used in declination, only +/-). That's easy.
Right ascension, however, is a bit different. Because the Earth rotates once on its axis in 24 hours, there are 24 hour lines of right ascension (subdivided into minutes and seconds). This differs from longitude on Earth (which has 0-180º E and 0-180º W). The 24 hours of right ascension increase to the west (clockwise around the celestial globe as viewed from above its North Pole).
This time of year, a prominent star in the evening sky is Vega. Vega has a declination of +38º 47’ 37” (almost 39º north of the celestial equator). It has a right ascension of 18h 37m 18s (the abbreviations are hours, minutes, and seconds). It always has the same declination and right ascension, not matter what time of day or night or what location on Earth you’re viewing it from. In order to understand why that is, we have to complicate things a bit.
When looking at the celestial globe, imagine that the Earth is fixed and not moving. Then imagine the celestial sphere rotating around the Earth once every a day (there’s a complication here, it’s actually once every 23 hours and 56 minutes, not 24 hours, because the Earth is also going around the Sun as it rotates but don't worry about that here). So the star, and the declination/right ascension coordinate system ,are both rotating around the Earth (that’s why the star’s declination and right ascension are constant even though we see the stars moving through the sky during the course of the night - the coordinate system is moving too).
Now, just as with longitude on the Earth, there’s a problem when setting up right ascension. Where do you place the 00 hour line of right ascension? Once again, it’s arbitrary but a logical place was chosen. To understand, another complication must be discussed!
Look back at the celestial globe picture again. Notice how the north and south pole of the Earth are not oriented vertically but tilted. The amount of tilt is 23.5º from vertical. Why? Because the Earth’s axis is tilted by that amount. Tilted with respect to what? Tilted with respect to the Earth’s orbit around the Sun called the plane of the ecliptic. Imagine all of the planets in our solar system orbiting the Sun. They all orbit (roughly) in the same plane. From here on Earth, we see the Sun move across the sky between sunrise and sunset. The Sun is following the path of the ecliptic in the sky (on the Sun, we’d see the Earth following the path of the ecliptic in the sky – it goes both ways!). In the image below, all the planetary orbits define the plane of the ecliptic.
Back to the celestial globe. See the band of metal circling the celestial globe dividing it in half horizontally? That’s essentially where the ecliptic would be located. See the seam on the celestial globe halfway between the celestial poles? That’s the celestial equator. Note that the plane of the celestial equator and the plane of the ecliptic are at an angle from each other (a 23.5º angle). The band of the ecliptic and the band of the celestial equator intersect each other at two points. One of these points is defined as the 00 hour of right ascension. It actually corresponds physically to the spring or vernal equinox (the other intersection is the fall or autumnal equinox).
Examine the picture above. It shows the celestial sphere. The red line with the Sun on it is the ecliptic and the blue line is the celestial equator. Where they intersect is the vernal equinox. That’s the 00 hour line of right ascension.
Also note, in this figure, that right ascension hours increase to the right (counterclockwise when looking down from above the north celestial pole). Why? Because the celestial sphere is rotating around the Earth from east to west in a clockwise direction (imagine standing on the stationary Earth inside the celestial sphere, you’d see stars rising in the east and setting in the west just as you do in real life).
When you understand right ascension and declination, you now can look up the "address" of any object in the sky and know where it's located.
Saturday, September 25, 2010
Latitude & Longitude
In all of the courses I'm teaching this semester, students have to be familiar with the concept of latitude and longitude. Latitude and longitude allow you to specify an exact location on the Earth’s spherical surface. In geology, it's important because we work with maps and in astronomy it's important because it helps to understand right ascension and declination - a coordinate system used for celestial objects (subject of tomorrow's post).
Let’s start with a digression… In mathematics, a circle is traditionally divided into 360 equal parts called degrees (º). Blame the ancient Babylonians for this – they used a base 60 number system (same reason we have 60 seconds in a minute and 60 minutes in an hour). The origin of 360º arose because it was 6 x 60º and these numbers came up in some geometrical problems they were working on at the time. Still around over 3,500 years later, go figure!
Sometimes, degrees are a little large for your measurement purposes so you need a smaller subdivision of a degree. Once again, taking our cue from the Babylonians, we can subdivide a degree into 60 smaller units called arcminutes (sometimes they’re just called “minutes” but people confuse that with time on a clock which it has nothing to do with so I’ll use the term arcminutes). An arcminute can be similarly subdivided into 60 arcseconds (also often just called seconds). This means there are 60 x 60 or 3,600 arcseconds in 1º. The symbol for arcminutes is the single quotation (’) and the symbol for arcseconds is the double quotation (”).
We can therefore express an angular measure as 14º 15’ 18” which is far more precise than saying it’s “around” 14º. We can also specify accurate angular measurements in decimal notation instead of degree-minute-second notation. Since there are 60 minutes in a degree and 3,600 seconds in a degree, we can rewrite 14º 15” 18” as:
14º + (15” / 60”/º) + (18” / 3,600”/º) = 14º + (0.25)º + (0.005)º = 14.255º
Similarly, if we were given an angular measurement of 72.765º, how do we convert it to degree-minute-second notation?
Start with 72º
Then multiply 0.765º by (60’ / 1º) = 45.9’. Keep the 45’ and carry the 0.9’
Take that remainder of 0.9’ and multiply it by (60” / 1’) = 54”
Put them together to get 72º 45’ 54”
Digression over, now let’s look at latitude.
The Earth is a sphere (roughly, but for our purposes we can assume it’s exactly that). The Earth also rotates on its axis once every 24 hours. This gives two poles of rotation which we call the North Pole and the South Pole. We can draw a line on the Earth halfway between the North and South Poles and call it the Equator. It divides the Earth into a Northern and Southern Hemisphere (“hemisphere” literally means “half a sphere”).
The Equator is defined as the reference line for latitude and we say that any point on the Equator lies at 0º of latitude. Since traveling from the Equator to the North Pole means you have traveled ¼ of the way around the sphere of the Earth, we then define the North Pole as 90º North latitude (¼ of the way around 360º is 360 º/4 = 90º). Similarly, the South Pole is now defined as 90º South latitude. Between the Equator and the Poles, we can draw 90 equally-spaced lines of latitude each a degree apart.
The college where I teach lies close to the 42º N line of latitude. We’re roughly 42º north of the Equator (almost half way to the North Pole). While we’re close to this line of latitude, we’re not exactly on it and herein lies a problem. If you go to Wikipedia and look up “Earth,” you will see that the meridional circumference (meridians are north-south lines so another way of saying this is the polar circumference) of the Earth is 40,008 km. Divide this by 4 and you’ll have the distance from the Equator to the Pole which is 10,002 km. Divide this by the 90 lines of latitude between the Equator and the Pole and you’ll see that each line of latitude covers 111 km (rounded off). For those who are metrically-impaired, 111 km is about 69 miles. So when we say that the my college lies close to the 42º N line of latitude, it means we could be as far as 34.5 miles away from it (69 mi / 2).
That’s why we have to worry about arcminutes and arcseconds. They locate our position on the Earth’s surface far more accurately. Since each degree line of latitude covers about 111 km of distance, we can see that each arcsecond of latitude covers 0.0308 km (111 km / 3,600). That’s 30.8 meters (there are 1,000 meters in a kilometer). So if we specify our location to the nearest arcsecond, that will get us within ± 15.4 meters (30.8 m / 2) of the exact spot. That’s about 50 feet – close enough for many purposes (including ours). If you want to even be more exact, you can specify tenths or hundredths of an arcsecond (the U.S. military likes this degree of precision when launching things like cruise missiles).
So, to be more precise, my office at the college is best specified with a latitude of 41º 51’ 02.50” N. That kind of precision is ± 15.4 cm (± 6 inches)! Pretty damn good.
Now let’s look at longitude. Longitude lines, called meridians, run from pole to pole and are a bit more problematic because we can place the 0º longitude reference line anywhere. In the past, people have tried to locate it in places like Jerusalem, Paris, Copenhagen, Rome, St. Petersburg, and even Philadelphia. It ended up, however, in England running through the Royal Observatory in the area of greater London called Greenwich.
Why England? Because back in the 1700s the English needed, and were developing, accurate maps for seafaring and England was the dominant naval power of the day (a 1740 patriotic song still sung today has the line “"Rule, Britannia! rule the waves!”). They made a lot of maps placing 0º longitude in Greenwich. After much arguing among countries, an international conference in 1884 made it official, the Prime Meridian, or zero line of longitude, was defined to run through Greenwich, England.
The Prime Meridian now divides the Earth into an Eastern and Western Hemisphere (we’re in the Western Hemisphere here in the U.S.). Longitude lines go east or west of the Prime Meridian to the opposite side of the globe, in the middle of the Pacific Ocean, where they meet at the International Date Line which has a longitude of 180º E or W (doesn’t matter). Why 180º? Because you’ve gone halfway around the globe and 360º / 2 = 180º.
My office at the college has a longitude of 074º 07’ 42.88” W.
Remember that latitudes will always have N or S designations and longitudes will always have E or W designations (unless it’s assumed – for example, a location in the U.S. will always be N latitude and W longitude).
One other note, many computer programs require you to enter latitude and longitude as plus (+) or minus (-) instead of N/S or E/W. In this system, N latitudes are positive and S latitudes are negative. E longitudes are positive and W longitudes are negative. In this system, my office's location would be:
+41º 51’ 02.50” for the latitude and -074º 07’ 42.88” for the longitude.
Easy.
Let’s start with a digression… In mathematics, a circle is traditionally divided into 360 equal parts called degrees (º). Blame the ancient Babylonians for this – they used a base 60 number system (same reason we have 60 seconds in a minute and 60 minutes in an hour). The origin of 360º arose because it was 6 x 60º and these numbers came up in some geometrical problems they were working on at the time. Still around over 3,500 years later, go figure!
Sometimes, degrees are a little large for your measurement purposes so you need a smaller subdivision of a degree. Once again, taking our cue from the Babylonians, we can subdivide a degree into 60 smaller units called arcminutes (sometimes they’re just called “minutes” but people confuse that with time on a clock which it has nothing to do with so I’ll use the term arcminutes). An arcminute can be similarly subdivided into 60 arcseconds (also often just called seconds). This means there are 60 x 60 or 3,600 arcseconds in 1º. The symbol for arcminutes is the single quotation (’) and the symbol for arcseconds is the double quotation (”).
We can therefore express an angular measure as 14º 15’ 18” which is far more precise than saying it’s “around” 14º. We can also specify accurate angular measurements in decimal notation instead of degree-minute-second notation. Since there are 60 minutes in a degree and 3,600 seconds in a degree, we can rewrite 14º 15” 18” as:
14º + (15” / 60”/º) + (18” / 3,600”/º) = 14º + (0.25)º + (0.005)º = 14.255º
Similarly, if we were given an angular measurement of 72.765º, how do we convert it to degree-minute-second notation?
Start with 72º
Then multiply 0.765º by (60’ / 1º) = 45.9’. Keep the 45’ and carry the 0.9’
Take that remainder of 0.9’ and multiply it by (60” / 1’) = 54”
Put them together to get 72º 45’ 54”
Digression over, now let’s look at latitude.
The Earth is a sphere (roughly, but for our purposes we can assume it’s exactly that). The Earth also rotates on its axis once every 24 hours. This gives two poles of rotation which we call the North Pole and the South Pole. We can draw a line on the Earth halfway between the North and South Poles and call it the Equator. It divides the Earth into a Northern and Southern Hemisphere (“hemisphere” literally means “half a sphere”).
The Equator is defined as the reference line for latitude and we say that any point on the Equator lies at 0º of latitude. Since traveling from the Equator to the North Pole means you have traveled ¼ of the way around the sphere of the Earth, we then define the North Pole as 90º North latitude (¼ of the way around 360º is 360 º/4 = 90º). Similarly, the South Pole is now defined as 90º South latitude. Between the Equator and the Poles, we can draw 90 equally-spaced lines of latitude each a degree apart.
The college where I teach lies close to the 42º N line of latitude. We’re roughly 42º north of the Equator (almost half way to the North Pole). While we’re close to this line of latitude, we’re not exactly on it and herein lies a problem. If you go to Wikipedia and look up “Earth,” you will see that the meridional circumference (meridians are north-south lines so another way of saying this is the polar circumference) of the Earth is 40,008 km. Divide this by 4 and you’ll have the distance from the Equator to the Pole which is 10,002 km. Divide this by the 90 lines of latitude between the Equator and the Pole and you’ll see that each line of latitude covers 111 km (rounded off). For those who are metrically-impaired, 111 km is about 69 miles. So when we say that the my college lies close to the 42º N line of latitude, it means we could be as far as 34.5 miles away from it (69 mi / 2).
That’s why we have to worry about arcminutes and arcseconds. They locate our position on the Earth’s surface far more accurately. Since each degree line of latitude covers about 111 km of distance, we can see that each arcsecond of latitude covers 0.0308 km (111 km / 3,600). That’s 30.8 meters (there are 1,000 meters in a kilometer). So if we specify our location to the nearest arcsecond, that will get us within ± 15.4 meters (30.8 m / 2) of the exact spot. That’s about 50 feet – close enough for many purposes (including ours). If you want to even be more exact, you can specify tenths or hundredths of an arcsecond (the U.S. military likes this degree of precision when launching things like cruise missiles).
So, to be more precise, my office at the college is best specified with a latitude of 41º 51’ 02.50” N. That kind of precision is ± 15.4 cm (± 6 inches)! Pretty damn good.
Now let’s look at longitude. Longitude lines, called meridians, run from pole to pole and are a bit more problematic because we can place the 0º longitude reference line anywhere. In the past, people have tried to locate it in places like Jerusalem, Paris, Copenhagen, Rome, St. Petersburg, and even Philadelphia. It ended up, however, in England running through the Royal Observatory in the area of greater London called Greenwich.
Why England? Because back in the 1700s the English needed, and were developing, accurate maps for seafaring and England was the dominant naval power of the day (a 1740 patriotic song still sung today has the line “"Rule, Britannia! rule the waves!”). They made a lot of maps placing 0º longitude in Greenwich. After much arguing among countries, an international conference in 1884 made it official, the Prime Meridian, or zero line of longitude, was defined to run through Greenwich, England.
The Prime Meridian now divides the Earth into an Eastern and Western Hemisphere (we’re in the Western Hemisphere here in the U.S.). Longitude lines go east or west of the Prime Meridian to the opposite side of the globe, in the middle of the Pacific Ocean, where they meet at the International Date Line which has a longitude of 180º E or W (doesn’t matter). Why 180º? Because you’ve gone halfway around the globe and 360º / 2 = 180º.
My office at the college has a longitude of 074º 07’ 42.88” W.
Remember that latitudes will always have N or S designations and longitudes will always have E or W designations (unless it’s assumed – for example, a location in the U.S. will always be N latitude and W longitude).
One other note, many computer programs require you to enter latitude and longitude as plus (+) or minus (-) instead of N/S or E/W. In this system, N latitudes are positive and S latitudes are negative. E longitudes are positive and W longitudes are negative. In this system, my office's location would be:
+41º 51’ 02.50” for the latitude and -074º 07’ 42.88” for the longitude.
Easy.
Friday, September 24, 2010
Challenging quotation
I like this quotation attributed to author Isak Dinesen:
When you are sure a task is utterly beyond your powers, approach it one day at a time, without hope and without despair.
Isak Dinesen was the pen name of Karen von Blixen-Finecke who was best known for having written Out of Africa.
This is advice I need to take to heart as I work on way too many projects and feel like the whole thing is about to wheel out of control at any second!
When you are sure a task is utterly beyond your powers, approach it one day at a time, without hope and without despair.
Isak Dinesen was the pen name of Karen von Blixen-Finecke who was best known for having written Out of Africa.
This is advice I need to take to heart as I work on way too many projects and feel like the whole thing is about to wheel out of control at any second!
Thursday, September 23, 2010
Rocket Day
Spent yesterday afternoon with a bunch of homeschooled kids (including my own) launching model rockets at a local park. The sun was out and it was surprisingly warm for the equinox day in late September. I'm very fortunate to have the kind of job where I can slip out for 3 hours and play (of course I also have the type of job where I'm on the computer working 10 pm on a Sunday night).
Here's my rocket (I built one too) on my homemade launch pad (a piece of aluminum screwed to a pressure-treated wood base with a rod stuck into it) ready to go. The other pic is me hooking up one of the kid's rockets. I didn't include pictures of the kids since most of them weren't mine.
We have liftoff. Rockets are fun, but they can be educational as well.
Here's my rocket (I built one too) on my homemade launch pad (a piece of aluminum screwed to a pressure-treated wood base with a rod stuck into it) ready to go. The other pic is me hooking up one of the kid's rockets. I didn't include pictures of the kids since most of them weren't mine.
Here's my launch controller. I'm proud of this since I built it myself from scratch (simple circuit inside, it's only job is to connect a 9V battery to those black and red lugs). The blue pushbutton turns it on and off. When it's on, a blue LED lights. The key switch arms it and turns on the red LED (when I'm setting up the rocket I have the key so no one can shoot a rocket off into my face!). The red momentary pushbutton connects the battery to the lugs. The current flows through two wires to the rocket igniter in the engine.
So, from a safe distance, the kids can arm the system, we have a countdown, and then whoosh!
We have liftoff. Rockets are fun, but they can be educational as well.
Wednesday, September 22, 2010
Happy Equinox!
Today is the Autumnal Equinox - the half way point between the longest day of the year on the Summer Solstice (June 21) and the shortest day of the year on the Winter Solstice (December 21). Equinox comes from Latin for "equal night" because day and night are each about 12 hours in length on this date (in summer, days are about 15 hours long and in winter they're about 9 hours long at our mid-latitude location in NY).
The reason for the change in seasons is not what most people immediately think when asked. It's not due to the changing distance from the Earth to the Sun (while the Earth's orbit is elliptical, it's not by much and the difference is only about 3%). As a matter of fact we're closest to the Sun in early January.
The reason for seasons, and why we can mark solstices and equinoxes, is because the Earth's axis is tilted by about 23.5°. In the Northern Hemisphere summer, we're tilted toward the Sun (and the Southern Hemisphere is tilted away and has winter) and vice versa six months later. On the Summer Solstice, when we have maximum tilt toward the Sun, the Sun is directly over 23.5° N latitude - the Tropic of Cancer. On the Winter Solstice, when we have maximum tilt away from the Sun, the Sun is directly over 23.5° S latitude - the Tropic of Capricorn. On the equinox, like today, the Sun is directly over the Earth's Equator.
In modern Wicca, the Autunmnal Equinox is called Mabon after a Welsh diety. Mabon is sometimes also known as the Feast of the Ingathering and is based on a traditional harvest festival. Many ancient cultures knew about and certainly celebrated the equinox in some way. The Mayan city of Dzibilchaltun, built around 200 AD (some argue for an earlier date), has a temple called the Temple of the Seven Dolls. Every equinox, the Sun shines through a passageway in the temple. It was intentional.
Halfway around the world at the Loughcrew megalithic cairn T in Ireland, some 5,000 years old, the equinox sunrise illuminates a passage and an engraved panel at the end.
There are numerous other archeoastronomy sites around the world which show similar alignments. It's only natural to mark the passage into the "dark" part of the year.
The reason for the change in seasons is not what most people immediately think when asked. It's not due to the changing distance from the Earth to the Sun (while the Earth's orbit is elliptical, it's not by much and the difference is only about 3%). As a matter of fact we're closest to the Sun in early January.
The reason for seasons, and why we can mark solstices and equinoxes, is because the Earth's axis is tilted by about 23.5°. In the Northern Hemisphere summer, we're tilted toward the Sun (and the Southern Hemisphere is tilted away and has winter) and vice versa six months later. On the Summer Solstice, when we have maximum tilt toward the Sun, the Sun is directly over 23.5° N latitude - the Tropic of Cancer. On the Winter Solstice, when we have maximum tilt away from the Sun, the Sun is directly over 23.5° S latitude - the Tropic of Capricorn. On the equinox, like today, the Sun is directly over the Earth's Equator.
In modern Wicca, the Autunmnal Equinox is called Mabon after a Welsh diety. Mabon is sometimes also known as the Feast of the Ingathering and is based on a traditional harvest festival. Many ancient cultures knew about and certainly celebrated the equinox in some way. The Mayan city of Dzibilchaltun, built around 200 AD (some argue for an earlier date), has a temple called the Temple of the Seven Dolls. Every equinox, the Sun shines through a passageway in the temple. It was intentional.
Halfway around the world at the Loughcrew megalithic cairn T in Ireland, some 5,000 years old, the equinox sunrise illuminates a passage and an engraved panel at the end.
There are numerous other archeoastronomy sites around the world which show similar alignments. It's only natural to mark the passage into the "dark" part of the year.
Tuesday, September 21, 2010
Phobos
Phobos and Deimos ("Fear" and "Terror" in Greek) are the two small moons of Mars. Phobos, the larger of the two at roughly 28 x 20 x 18 km, has too low a density to be solid rock and is in a decaying orbit around Mars. Its distance from Mars is decreasing by 1.8 m per century and in 50 million years or so it will likely break up from gravitational tidal forces forming a ring of material around the planet. As you can see, it's heavily pocked and streaked from meteorite impacts.
In the past, Phobos and Deimos were thought to be captured asteroids due to their asteroid-like irregular shapes and small size. Mars also lies close to the asteroid belt although the low density of the moons suggest an ice and rock composition found in objects further out in the solar system (trans-Neptunian objects).
New data from the Mars Express spacecraft, a European Space Agency mission, indicates that Phobos (and by analogy Deimos) may have formed from accretion of material tossed into orbit by a collision of an asteroid with the surface of Mars (kind of like how our moon formed but on a smaller scale). Examining Phobos at thermal infrared wavelengths with the Planetary Fourier Spectrometer (PFS) revealed a composition that didn't really match any known asteroids (but was similar to Mars) and a group of minerals called phyllosilicates were also detected.
Phyllosilicates are essentially the micas and clay minerals and generally form in the presence of water. Phobos is too small to ever have had liquid water but Mars was at one time wet. These minerals may well have formed on the Martian surface a few billion years ago and found their way into the moon by an impact on Mars.
In addition, the spacecraft was able to very accurately measure the mass of Phobos from its gravitational perturbation of the spacecraft's orbit and came up with a density for the moon of 1.86 ± 0.02 g/cm3. Given that the average density of silicate rocks is around 2.7 g/cm3, this is a low density. This low density can be explained if Phobos is full of voids (anywhere from 25-45% of its interior) and this is consistent with the collision-accretion model of its formation. Phobos is basically a rubble pile held together by gravity.
The porosity of Phobos would also explain why it didn't break up when crater Stickney formed (see that huge "dimple" in the image above?). This internal structure allowed the moon to absorb all the energy from that impact without blasting apart.
This new data was presented by Marco Giuranna, a researcher from the Istituto di Fisica dello Spazio Interplanetario at the European Planetary Science Congress running from September 19-24 in Rome.
Sunday, September 19, 2010
Jupiter
You may have noticed a very bright "star" in the east over the past few weeks. It's actually the planet Jupiter and it's brighter than normal during September. Easy to find, just go out after dark and look toward the southeast - Jupiter will be the brightest thing in the sky.
On Monday, September 20, Jupiter will be closer to Earth than it will be at any time between 1963 and 2022 (it's still some 368 million miles away). It's a beautiful sight, even in a small telescope.
Need a telescope for this view!
Saturday, September 18, 2010
Thursday, September 16, 2010
Come to sunny Mexico in January
I'm running a trip to Mexico from January 3-12, 2011 to study ancient astronomy & the Maya. No prerequisites necessary, can take it for 3 credits or personal enrichment, and it's a hell of a lot better than shoveling snow in the Hudson Valley.
Check out my website here: http://people.sunyulster.edu/schimmrs/Mexico2011/
If anyone's interested, constact me ASAP, the first deposit is due September 29!
Wednesday, September 15, 2010
If I was ruler of the world...
I'd make people use the following calendar:
It divides up the 365.25 (rounded off) day year into four quarters where each of the three months in each quarter have 31, 30, and 30 days. Each quarter starts on a Sunday and ends on a Saturday. You can use this calendar every year. Every date always falls on the same day of the week each year (my birthday will always be on a Tuesday).
Since 4 months of 31 days (124) plus 8 months of 30 days (240) adds up to 364 days, we need another day. This calendar solves the problem by creating a Worldsday (W) after December 31 and before January 1. It's a global holiday and is not assigned a day of the week. Technically, a day like this is called an intercalary day (extra days inserted to align the calendar).
Because there's 1/4 day every year we have to worry about too, they insert another Worldsday after June 30 and before July 1 every 4 years (Leap Years) - unless they're centennial years (those ending in -00) not evenly divisible by 400 (that's what we do with our present calendar too, by the way).
I think it's pretty cool. It would actually save society tremendous amounts of time and money. As an example, every two years, when we update our college catalog, committees of people meet for hours to develop the academic calendar for the next two years - when classes start, when all the holidays are (if a holiday falls on a Tuesday, we need to make up that Tuesday somewhere else), when final exams are, etc. You also don't have to print new calendars every year. Imagine the savings for financial institutions in calculating quarterly reports. With this calendar, you make up a schedule once and it's good for perpetuity.
The only glitch in all of this are some religious holidays (e.g. Yom Kippur, Passover, Good Friday, Easter) which are based on the ancient Hebrew lunar calendar and have the holidays bouncing all over the place. That's the main objection - a literal reading of the Judeo-Christian Bible holds that the 7th day (Friday? Saturday? Sunday?) is the Sabbath and needs to be kept holy. The intercalary Worldsday disrupts that cycle and I guess some think it will make God mad.
Why don't we use this great calendar? Who knows, people have been advocating its adoption since 1930.
Read more about it at http://www.theworldcalendar.org/.
It divides up the 365.25 (rounded off) day year into four quarters where each of the three months in each quarter have 31, 30, and 30 days. Each quarter starts on a Sunday and ends on a Saturday. You can use this calendar every year. Every date always falls on the same day of the week each year (my birthday will always be on a Tuesday).
Since 4 months of 31 days (124) plus 8 months of 30 days (240) adds up to 364 days, we need another day. This calendar solves the problem by creating a Worldsday (W) after December 31 and before January 1. It's a global holiday and is not assigned a day of the week. Technically, a day like this is called an intercalary day (extra days inserted to align the calendar).
Because there's 1/4 day every year we have to worry about too, they insert another Worldsday after June 30 and before July 1 every 4 years (Leap Years) - unless they're centennial years (those ending in -00) not evenly divisible by 400 (that's what we do with our present calendar too, by the way).
I think it's pretty cool. It would actually save society tremendous amounts of time and money. As an example, every two years, when we update our college catalog, committees of people meet for hours to develop the academic calendar for the next two years - when classes start, when all the holidays are (if a holiday falls on a Tuesday, we need to make up that Tuesday somewhere else), when final exams are, etc. You also don't have to print new calendars every year. Imagine the savings for financial institutions in calculating quarterly reports. With this calendar, you make up a schedule once and it's good for perpetuity.
The only glitch in all of this are some religious holidays (e.g. Yom Kippur, Passover, Good Friday, Easter) which are based on the ancient Hebrew lunar calendar and have the holidays bouncing all over the place. That's the main objection - a literal reading of the Judeo-Christian Bible holds that the 7th day (Friday? Saturday? Sunday?) is the Sabbath and needs to be kept holy. The intercalary Worldsday disrupts that cycle and I guess some think it will make God mad.
Why don't we use this great calendar? Who knows, people have been advocating its adoption since 1930.
Read more about it at http://www.theworldcalendar.org/.
Tuesday, September 14, 2010
Holy crap!
Yes, this is for real.
A bunch of religious loons decided to hold a conference in support of geocentrism - the idea that the Sun and planets orbit a stationary Earth. It's the Biblical worldview but hasn't been much in vogue since Galileo starting looking at the sky with a telescope in 1609.
Robinson, G.L. 1913. Leaders of Israel. NY: Association Press
Even most young-Earth creationists tend to think these guys are nuts.
Monday, September 13, 2010
Tupelo
"She’s as sweet as tupelo honey" - Van Morrison
Black Tupelo (Nyssa sylvatica) is a tree I learned about recently. Back in July, I found a small freshly broken tree (probably from a recent thunderstorm) from which I scavenged some wood from for a project I was working on. I tried to identify the tree using my handy Trees of New York book (always in my backpack) but was unsuccessful. Coincidentally, a couple of days later, I was with a naturalist at Lake Minnewaska State Park and saw the exact same type of tree. Upon asking what it was, I was told it was a tupelo (which also goes by other names such as sourgum, blackgum, and pepperidge).
I didn't recognize it in the tree book because the book showed the leaves as highly glossy and my tree didn't have those glossy leaves. Turns out that's a natural variation - sometimes the leaves are not glossy (which is why it can be so tricky to identify plants from a book - also why, in geology labs, I always tell my students not to rely on color to identify minerals - look at their physical properties like hardness, cleavage, crystal form, etc).
The fall tree will have berry-like fruits so I'll have to hike back up in a few weeks and make sure I correctly identified it.
Photos from Wikipedia. The Latin name Nyssa sylvatica mean "water nymph of the woods" since many species of tupelo are tolerant of wet conditions and will grow in southern swamps.
Tupelo's interesting also for the fact that the tree's flowers are frequented by bees and, down in the Deep South, tupelo honey is popular. Once I learned that I had to get a jar to taste it - it is very good (random fact - the "gold" in Peter Fonda's movie Ulee's Gold is tupelo honey).
Black Tupelo (Nyssa sylvatica) is a tree I learned about recently. Back in July, I found a small freshly broken tree (probably from a recent thunderstorm) from which I scavenged some wood from for a project I was working on. I tried to identify the tree using my handy Trees of New York book (always in my backpack) but was unsuccessful. Coincidentally, a couple of days later, I was with a naturalist at Lake Minnewaska State Park and saw the exact same type of tree. Upon asking what it was, I was told it was a tupelo (which also goes by other names such as sourgum, blackgum, and pepperidge).
The fall tree will have berry-like fruits so I'll have to hike back up in a few weeks and make sure I correctly identified it.
Photos from Wikipedia. The Latin name Nyssa sylvatica mean "water nymph of the woods" since many species of tupelo are tolerant of wet conditions and will grow in southern swamps.
Tupelo's interesting also for the fact that the tree's flowers are frequented by bees and, down in the Deep South, tupelo honey is popular. Once I learned that I had to get a jar to taste it - it is very good (random fact - the "gold" in Peter Fonda's movie Ulee's Gold is tupelo honey).
Sunday, September 12, 2010
Here comes Igor
A few days ago I wrote about Igor, a tropical storm over by the Cape Verde Islands off Africa. Well, as I predicted, Igor strengthened into a hurricane over the past few days and now is a catagory 4 - hurricanes are ranked on the Saffir-Simpson scale from catagory 1 (weakest) to catagory 5 (strongest) based on sustained wind speeds.
It's still way out in the Atlantic but it's slowly moving WNW towards the southern U.S. It's not likely to weaken, there's plenty of warm water out there (it's like gasoline for a hurricane), and little to interfere with it. By the end of the week, you'll be hearing more about it as it approaches the U.S.
By the way, here's a link to a hilarious video parody from The Onion spoofing how those of us in the U.S. ignore hurricanes unless they directly threaten us.
It's still way out in the Atlantic but it's slowly moving WNW towards the southern U.S. It's not likely to weaken, there's plenty of warm water out there (it's like gasoline for a hurricane), and little to interfere with it. By the end of the week, you'll be hearing more about it as it approaches the U.S.
By the way, here's a link to a hilarious video parody from The Onion spoofing how those of us in the U.S. ignore hurricanes unless they directly threaten us.
Saturday, September 11, 2010
The original solar cell
A morning glory leaf soaking up sunlight. Little pores (stomata) on the surface of the leaf pull in CO2 from the atmosphere.
Roots extract water (H2O) from the soil and special tissues (xylem) transport this water to the leaves.
Sunlight provides the energy for the following reaction called photosynthesis:
6 CO2 + 6 H2O ==> C6H12O6 + 6 O2
Six molecules of carbon dioxide (CO2) plus 6 molecules of water (H2O) will yield one molecule of sugar (glucose - C6H12O6) and six molecules of oxygen (O2). The oxygen is released back into the atmosphere through the stomata and the glucose provides energy for cells (animals get glucose by eating and breaking down food) and are the building blocks of starches.
Earth's early atmosphere was esentially carbon dioxide (like those of Venus and Mars today at 96-97% CO2). Early in the history of life (over 3 billion years ago), a group of bacteria called the cyanobacteria, developed the ability to do photosynthesis. Over a couple of billion years, their then poisonous waste product, molecular oxygen (O2), gradually built up in the atmosphere allowing for the evolution of animal life (and eventually us).
Friday, September 10, 2010
My wife's and my fantasy
Get your mind out of the gutter, it's not that kind of fantasy!
Each year we receive our school tax bill - it's a bit over $3,000 this year and it's always difficult to dig up enough money to pay it (which is why I teach over the summer and am basically a whore doing just about anything for a few extra dollars).
Since we home school, we not only get no benefit from this (as do many people without kids in the local schools), we also have to pay out-of-pocket (with no tax breaks) for our own educational supplies. We spend another few thousand a year for all of that.
So each year we dream of how nice it would be to actually be able to use that school tax money to educate our own kids. I know, I know, it's necessary to support public education but the tax burden should not fall unfairly on property owners (especially elderly property owners who are forced out of their homes by the tax burden).
This summer we learned Rondout Valley School District spends over $19,000 per student per year to educate them in the schools! The national average is a little over $10,000 per students. New York schools are the highest in the nation in per capita students spending and Rondout's near the top of that list. Read about it here.
I also know that many local Ulster County schoolteachers earn well over $100,000 a year - twice what many PhD college professors earn in the local SUNY colleges and universities. Still they complain of being underpaid!
Well, for all that money, we must be getting an awesome education for our students, right? Well our local community college gets a lot of local high school graduates and many of them place into remedial English and mathematics classes after entrance testing. FACT: There are students graduating local high schools who cannot do simple 8th grade algebra nor write a coherent paragraph! How do you feel about that $19,000 per student per year now?
Just like some people fantasize about winning the lottery, my wife and I fantasize how nice it would be to have $38,000 per year to educate our two children! We could study marsupials in Australia! The French Revolution in France! Spanish language lessons in Cancun!
Instead I may have to pick up a second night job to pay my school tax bill.
Each year we receive our school tax bill - it's a bit over $3,000 this year and it's always difficult to dig up enough money to pay it (which is why I teach over the summer and am basically a whore doing just about anything for a few extra dollars).
Since we home school, we not only get no benefit from this (as do many people without kids in the local schools), we also have to pay out-of-pocket (with no tax breaks) for our own educational supplies. We spend another few thousand a year for all of that.
So each year we dream of how nice it would be to actually be able to use that school tax money to educate our own kids. I know, I know, it's necessary to support public education but the tax burden should not fall unfairly on property owners (especially elderly property owners who are forced out of their homes by the tax burden).
This summer we learned Rondout Valley School District spends over $19,000 per student per year to educate them in the schools! The national average is a little over $10,000 per students. New York schools are the highest in the nation in per capita students spending and Rondout's near the top of that list. Read about it here.
I also know that many local Ulster County schoolteachers earn well over $100,000 a year - twice what many PhD college professors earn in the local SUNY colleges and universities. Still they complain of being underpaid!
Well, for all that money, we must be getting an awesome education for our students, right? Well our local community college gets a lot of local high school graduates and many of them place into remedial English and mathematics classes after entrance testing. FACT: There are students graduating local high schools who cannot do simple 8th grade algebra nor write a coherent paragraph! How do you feel about that $19,000 per student per year now?
Just like some people fantasize about winning the lottery, my wife and I fantasize how nice it would be to have $38,000 per year to educate our two children! We could study marsupials in Australia! The French Revolution in France! Spanish language lessons in Cancun!
Instead I may have to pick up a second night job to pay my school tax bill.
Thursday, September 9, 2010
Rosh Hoshanah
Happy new year to my Jewish friends.
Rosh Hoshanah began last night at sundown. In Hebrew (ראש השנה), it means "head of the year" and marks the start of the traditional Jewish civil year. It's followed 10 days later by Yom Kippur, the Day of Atonement. Sundown on Rosh Hashanah is marked by the blowing of the shofar (a ram's horn) and followed by a day of rest (and typically a dinner with family and a service at the temple as well).
Why do Jewish holidays begin at sundown? Because in Genesis 1, the creation story has the repeating refrain "And there was evening, and there was morning - the # day." (where # is 1st, 2nd, etc.). For whatever reason , the ancient Hebrews saw sundown as the beginning of the new day.
So why is a science/education blogger writing about this? There are two interesting things here. The first is that, on the Jewish calendar, today begins the first day of the year 5,771. Why 5,771? Because, it's been 5,771 years since the creation of the world by God as described in Genesis 1.
Now "evilutionist" geologists like me would respond that the Earth is not less than 6,000 years old, there is abundant, compelling evidence for an age closer to 4.5 billion (750,000 times older!). One day I'll post a bit about how 18th and 19th century geologists, long before radiometric dating, came up with an ancient age for the Earth just by looking at rocks and applying a bit of logical reasoning.
Now of course, most modern Jews, like most Christians, accept the results of modern science and don't really believe in such a young Earth but there are some in the Orthodox community, like many Evangelical Christians, who do believe that the Earth is, in fact, a few thousand years old. Why?
Here's the reason from an Orthodox Rabbi creationist:
From the Answers in Genesis Christian creationist website:
Pretty similar! If the Torah/Bible says it, it must be true. Personally, I don't think we should learn science from a text thousands of years old from a desert nomad community, especially when it conflicts with what we see in front of us with our own eyes, but that's just me.
The other interesting thing about Rosh Hashanah, at least from my perspective as an instructor for a course in Ancient Astronomy, is that it's based on a lunar calendar (like the date of Easter in the Christian tradition or Ramadan in Islam). That's why such holidays don't fall on the same day each year.
The Jewish calendar is best called a lunisolar calendar since it based on both moon phases (the derivation of our word "month") and leap months are periodically added to keep it in sync with the tropical year (the year defined by solstices and equinoxes). It's composed of 12 months of 29 or 30 days:
Nisan (30 days), Iyar (29 days), Sivan (30 days), Tammuz (29 days), Av (30 days), Elul (29 days), Tishrei (30 days), Cheshvan (29 or 30 days), Kislev (29 or 30 days), Tevet (29 days), Shevat (30 days), and Adar (29 days). During leap years, as 5,771 is, an extra month is added - Adar I of 30 days is inserted before Adar (which becomes Adar II) of 29 days.
Why alternations of 29 and 30 days? Because the number of days from new Moon to new Moon is 29.53059 days (29 d, 12 h, 44 m, 2.8 s) - this is called the synodic month. That fractional number of days makes it a real bitch to use phases of the Moon as a calendar (even though most ancient cultures, including the Hebrews, did so).
Why add the extra month during leap years? If you didn't, the holidays would shift out of the season (e.g. autumn) in which they're supposed to be observed and you have to get your cycle of Moon phases to somehow mesh with the tropical year (which rounds off to 365.24 days).
The Jewish calendar is synced with the Metonic cycle of 19 years, 12 of which are regular years and 7 are leap years (years 3, 6, 8, 11, 14, 17, and 19). Leap years are when the extra month are added. The Metonic cycle is named after Meton of Athens (5th century BCE) but was known as far back as the ancient Babylonians. Turns out that 19 x 365.24 d (# of days in a tropical year) = 6,939.56 d / 29.53 d (# of days in synodic month) = 235.00 cycles of phases (it's not exact, but pretty damn close). All lunar calendars sync to this Metonic cycle because of this coincidence (it's a coincidence of the human era because these values change over geologic/astronomic time periods).
Devising calendars that work is surprisingly difficult!
Rosh Hoshanah began last night at sundown. In Hebrew (ראש השנה), it means "head of the year" and marks the start of the traditional Jewish civil year. It's followed 10 days later by Yom Kippur, the Day of Atonement. Sundown on Rosh Hashanah is marked by the blowing of the shofar (a ram's horn) and followed by a day of rest (and typically a dinner with family and a service at the temple as well).
The LORD said to Moses, "Say to the Israelites: 'On the first day of the seventh month you are to have a day of rest, a sacred assembly commemorated with trumpet blasts. Do no regular work, but present an offering made to the LORD by fire.' " (Lev 23:23-24 NIV).
Why do Jewish holidays begin at sundown? Because in Genesis 1, the creation story has the repeating refrain "And there was evening, and there was morning - the # day." (where # is 1st, 2nd, etc.). For whatever reason , the ancient Hebrews saw sundown as the beginning of the new day.
So why is a science/education blogger writing about this? There are two interesting things here. The first is that, on the Jewish calendar, today begins the first day of the year 5,771. Why 5,771? Because, it's been 5,771 years since the creation of the world by God as described in Genesis 1.
Now "evilutionist" geologists like me would respond that the Earth is not less than 6,000 years old, there is abundant, compelling evidence for an age closer to 4.5 billion (750,000 times older!). One day I'll post a bit about how 18th and 19th century geologists, long before radiometric dating, came up with an ancient age for the Earth just by looking at rocks and applying a bit of logical reasoning.
Now of course, most modern Jews, like most Christians, accept the results of modern science and don't really believe in such a young Earth but there are some in the Orthodox community, like many Evangelical Christians, who do believe that the Earth is, in fact, a few thousand years old. Why?
Here's the reason from an Orthodox Rabbi creationist:
I underlined the word theories, for it is necessary to bear in mind, first of all, that science formulates and deals with theories and hypotheses while the Torah deals with absolute truths. These are two different disciplines, where reconciliation is entirely out of place.
From the Answers in Genesis Christian creationist website:
By definition, no apparent, perceived or claimed evidence in any field, including history and chronology, can be valid if it contradicts the scriptural record.
Pretty similar! If the Torah/Bible says it, it must be true. Personally, I don't think we should learn science from a text thousands of years old from a desert nomad community, especially when it conflicts with what we see in front of us with our own eyes, but that's just me.
The other interesting thing about Rosh Hashanah, at least from my perspective as an instructor for a course in Ancient Astronomy, is that it's based on a lunar calendar (like the date of Easter in the Christian tradition or Ramadan in Islam). That's why such holidays don't fall on the same day each year.
The Jewish calendar is best called a lunisolar calendar since it based on both moon phases (the derivation of our word "month") and leap months are periodically added to keep it in sync with the tropical year (the year defined by solstices and equinoxes). It's composed of 12 months of 29 or 30 days:
Nisan (30 days), Iyar (29 days), Sivan (30 days), Tammuz (29 days), Av (30 days), Elul (29 days), Tishrei (30 days), Cheshvan (29 or 30 days), Kislev (29 or 30 days), Tevet (29 days), Shevat (30 days), and Adar (29 days). During leap years, as 5,771 is, an extra month is added - Adar I of 30 days is inserted before Adar (which becomes Adar II) of 29 days.
Why alternations of 29 and 30 days? Because the number of days from new Moon to new Moon is 29.53059 days (29 d, 12 h, 44 m, 2.8 s) - this is called the synodic month. That fractional number of days makes it a real bitch to use phases of the Moon as a calendar (even though most ancient cultures, including the Hebrews, did so).
Why add the extra month during leap years? If you didn't, the holidays would shift out of the season (e.g. autumn) in which they're supposed to be observed and you have to get your cycle of Moon phases to somehow mesh with the tropical year (which rounds off to 365.24 days).
The Jewish calendar is synced with the Metonic cycle of 19 years, 12 of which are regular years and 7 are leap years (years 3, 6, 8, 11, 14, 17, and 19). Leap years are when the extra month are added. The Metonic cycle is named after Meton of Athens (5th century BCE) but was known as far back as the ancient Babylonians. Turns out that 19 x 365.24 d (# of days in a tropical year) = 6,939.56 d / 29.53 d (# of days in synodic month) = 235.00 cycles of phases (it's not exact, but pretty damn close). All lunar calendars sync to this Metonic cycle because of this coincidence (it's a coincidence of the human era because these values change over geologic/astronomic time periods).
Devising calendars that work is surprisingly difficult!
Wednesday, September 8, 2010
Igor
Igor is a tropical storm out by the Cape Verde Islands off western Africa. There's a reason many hurricanes are called Cape Verde hurricanes - it's a spawning ground. I think you'll start hearing a lot about Igor since it's moving westward and there's lots of warm water (fuel for hurricane development) and light wind shear (wind shear kills hurricanes) in its path. It has the potential for developing into a large and powerful hurricane when (if) it reaches North America in a week or so. Expect it to reach category 1 hurricane wind speeds (74-95 mph) by Friday or Saturday and strengthen as it plows westward across the bathtub-warm Atlantic.
If you're interested in following this, the National Hurricane Center is a great website.
Tuesday, September 7, 2010
Learning styles? Feh...
Just came across the following very interesting paper. Abstract viewable here.
Paschler, H., McDaniel, M., Rohrer, D., & Bjork, R. 2008. Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest 9 (3) : 105-119.
The idea behind learning styles (or "multiple intelligences") is that different people learn differently. Some are visual, some are auditory, some are kinesthetic or tactile, and others learn best from the written word. Students can take a learning styles inventory - basically a multiple-choice test that scores them in those different areas to see what their dominant learning style(s) is(are).
Teachers, from kindergarten to graduate school, are then urged, by educational "specialists" to be aware of the learning styles of our students and tailor our teaching to meet these needs. Sounds good, right?
Well, like many of the fads in education that come and go over the years, the concept of learning styles seems to be lacking some substance. To quote the authors of the study on learning styles:
I just wish research on teaching and learning were based more on sound scientific studies rather than feel-good bullshit.
I don't really worry about it in my geology classes anyway. Students who learn best from the written word have plenty to read, students who are auditory learners get it from my lectures, students who like tactile/kinesthetic things get to handle rocks and minerals and climb on rocks during field trips, and visual learners get lots of pretty PowerPoint pictures of geologic things to view during lecture. It's all good.
Quite honestly, if students want to succeed in college they better learn how to adapt to different professor's teaching styles not expect everyone to spoon-feed them material in a way that makes them feel comfortable. Learning is not opening your mind and allowing someone to pour in knowledge. Learning takes some effort and sometimes requires you to be uncomfortable.
Paschler, H., McDaniel, M., Rohrer, D., & Bjork, R. 2008. Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest 9 (3) : 105-119.
The idea behind learning styles (or "multiple intelligences") is that different people learn differently. Some are visual, some are auditory, some are kinesthetic or tactile, and others learn best from the written word. Students can take a learning styles inventory - basically a multiple-choice test that scores them in those different areas to see what their dominant learning style(s) is(are).
Teachers, from kindergarten to graduate school, are then urged, by educational "specialists" to be aware of the learning styles of our students and tailor our teaching to meet these needs. Sounds good, right?
Well, like many of the fads in education that come and go over the years, the concept of learning styles seems to be lacking some substance. To quote the authors of the study on learning styles:
Although the literature on learning styles is enormous, very few studies have even used an experimental methodology capable of testing the validity of learning styles applied to education. Moreover, of those that did use an appropriate method, several found results that flatly contradict the popular meshing hypothesis. We conclude therefore, that at present, there is no adequate evidence base to justify incorporating learning-styles assessments into general educational practice.
I just wish research on teaching and learning were based more on sound scientific studies rather than feel-good bullshit.
I don't really worry about it in my geology classes anyway. Students who learn best from the written word have plenty to read, students who are auditory learners get it from my lectures, students who like tactile/kinesthetic things get to handle rocks and minerals and climb on rocks during field trips, and visual learners get lots of pretty PowerPoint pictures of geologic things to view during lecture. It's all good.
Quite honestly, if students want to succeed in college they better learn how to adapt to different professor's teaching styles not expect everyone to spoon-feed them material in a way that makes them feel comfortable. Learning is not opening your mind and allowing someone to pour in knowledge. Learning takes some effort and sometimes requires you to be uncomfortable.
Saturday, September 4, 2010
Science & Beauty
When I heard the learn'd astronomer,When the proofs, the figures, were ranged in columns before me,When I was shown the charts and diagrams, to add, divide and measure them,When I sitting heard the astronomer where he lectured with much applause in the lecture-room,How soon unaccountable I became tired and sick,Till rising and gliding out I wander'd off by myself In the mystical moist night-air, and from time to time.Look'd up in perfect silence at the stars.
Leaves of Grass (1900)
Walt Whitman
Renown science and science fiction writer Isaac Asimov once wrote an essay (Science and Beauty) in response to Whitman's well-known poem. It was first published as an article in 1979 but later appeared in The Roving Mind, a collection of essays published in 1983.
Asimov (1920-1992) was a prolific writer (to say the least) having written or edited over 500 works spanning every major area of the Dewey decimal system except philosophy. Asimov was one of the reasons I gravitated toward science (or maybe my interest in science made me gravitate toward Asimov). His clear, direct prose appealed to me as a young teenager and I devoured his books on science (Asimov on Astronomy, Asimov on Physics, Asimov on Chemistry, etc., etc.).
Asimov always put a bit of himself in his books, after a few you felt that you knew him personally. Supposedly a great guy in person as well.
You can read Asimov's short essay here. It starts:
He goes on to write:I imagine that many people reading those lines tell themselves, exultantly, "How true! Science just sucks all the beauty out of everything, reducing it all to numbers and tables and measurements! Why bother learning all that junk when I can just go out and look at the stars?"
That is a very convenient point of view since it makes it not only unnecessary, but downright aesthetically wrong, to try to follow all that hard stuff in science. Instead, you can just take a look at the night sky, get a quick beauty fix, and go off to a nightclub.
But what I see - those quiet, twinkling points of light - is not all the beauty there is. Should I stare lovingly at a single leaf and willingly remain ignorant of the forest? Should I be satisfied to watch the sun glinting off a single pebble and scorn any knowledge of a beach?
For the rest of the essay, Asimov discusses what astronomers have learned about stars and planets (some of those points of light aren't stars at all). Cloud-shrouded worlds with toxic atmospheres, giant suns thousands of times brighter than our own, that virtually all the objects we see are part of a giant pinwheel galaxy spinning in space. He concludes:
And all of this vision- far beyond the scale of human imaginings -was made possible by the works of hundreds of "learn'd" astronomers ... Nor can we know or imagine now the limitless beauty yet to be revealed in the future - by science.
I love this because it's exactly how I feel about science. While I love being out and communing with nature, being out on a summer evening and staring at the stars (I did that last night out in the woods), there's far more to see in your mind's eye with some scientific knowledge.
That bright star in the east is Jupiter, the largest planet in our solar system, a world with liquid hydrogen oceans under its crushing gaseous atmosphere. Those four stars form the great square of Pegasus and that blurry spot to the left is the Andromeda Galaxy, the furthest object you can see with the naked eye over 2,000,000 light years away and composed of hundreds of billions of stars. That orange-colored star in the west is Arcturus, far enough away that to light you see tonight left the star back in 1973, and was emitted from a star that has used up all its hydrogen fuel and is now in old age as a helium burning orange-red giant.
People think science is dry and uninteresting. That it has a reductionist worldview that takes the mystery and awe out of the world. Maybe that's how it's often taught in basic science classes, and learning science can be difficult, but science is anything but dry and uninteresting. It's freakin' awesome!
Thursday, September 2, 2010
Mamas, don't let your babies grow up to be professors...
Apologies to Waylon Jennings and Willie Nelson for the post title...
Read an interesting article in Yahoo! Finance yesterday on 7 Jobs Companies are Desperate to Fill. Number 7 on the list was Geoscientist. It claims that the education required was a Bachelor's degree or higher and average annual earning are supposedly $79,160. Good PR for the students, many geology professors like myself will print this out and distribute it to their classes.
Of course, it's depressing news for me since it's my 14th year teaching at the college-level as full-time faculty and I still don't make the average salary listed above. We don't even get a cost-of-living increase this year because state and county funding of our community college is so bad that our contract was never re-negotiated (it expired on August 31).
Many people don't realize this, but a PhD with a decade of college-level teaching likely makes about the same as the night manager at your local fast-food place. And, if your PhD is in something like philosophy or medieval history, you might as well start applying to those fast-food places since academic jobs typically have hundreds of applicants for each position advertised in fields such as those.
It's funny how educated people such as myself have so little common sense that we end up working for much-lower wages than our colleagues in private industry (who have less student loans to pay off too!).
Read an interesting article in Yahoo! Finance yesterday on 7 Jobs Companies are Desperate to Fill. Number 7 on the list was Geoscientist. It claims that the education required was a Bachelor's degree or higher and average annual earning are supposedly $79,160. Good PR for the students, many geology professors like myself will print this out and distribute it to their classes.
Of course, it's depressing news for me since it's my 14th year teaching at the college-level as full-time faculty and I still don't make the average salary listed above. We don't even get a cost-of-living increase this year because state and county funding of our community college is so bad that our contract was never re-negotiated (it expired on August 31).
Foxtrot by Bill Amend
Many people don't realize this, but a PhD with a decade of college-level teaching likely makes about the same as the night manager at your local fast-food place. And, if your PhD is in something like philosophy or medieval history, you might as well start applying to those fast-food places since academic jobs typically have hundreds of applicants for each position advertised in fields such as those.
It's funny how educated people such as myself have so little common sense that we end up working for much-lower wages than our colleagues in private industry (who have less student loans to pay off too!).
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