Suppose I could get away with posting this on my office door? I'm going to start keeping a baseball bat by my desk...
Random thoughts and opinions of a community college geology professor living in the mid-Hudson Valley of New York State.
Monday, April 30, 2012
Thursday, April 26, 2012
My mood this week...
...is best summed up by this button (I want one of these!).
Pearls Before Swine is a great comic strip, by the way. This one from last week struck a chord. A faculty member recently told me "I don't read email." What the fuck? What white-collar job can you have in today's world where you can tell your supervisor "I didn't know about XYZ because don't read my email." and not get your lazy ass fired?
Sometimes I really, really, really want to be a complete asshole sociopath and just say what I think to people. Especially given some of the shit people have said to me lately. I also love how people are always wanting me to do shit for them without ever once doing the bare minimum for me (and, like an asshole, I just keep on doing what I think is the right thing).
At least tomorrow's Friday and I am eagerly anticipating a pint of liquid refreshment after work. Maybe two, one for each hand. Cheers.
Pearls Before Swine is a great comic strip, by the way. This one from last week struck a chord. A faculty member recently told me "I don't read email." What the fuck? What white-collar job can you have in today's world where you can tell your supervisor "I didn't know about XYZ because don't read my email." and not get your lazy ass fired?
Sometimes I really, really, really want to be a complete asshole sociopath and just say what I think to people. Especially given some of the shit people have said to me lately. I also love how people are always wanting me to do shit for them without ever once doing the bare minimum for me (and, like an asshole, I just keep on doing what I think is the right thing).
At least tomorrow's Friday and I am eagerly anticipating a pint of liquid refreshment after work. Maybe two, one for each hand. Cheers.
Monday, April 23, 2012
Friday, April 20, 2012
Coronal Rain
Cool movie from the Solar Optical Telescope on NASA/JAXA's Hinode spacecraft. This is from a solar flare on April 16 from Active Region 1461 over the eastern limb of the Sun.
The Sun has been fairly active lately and studded with sunspots. Here's today's solar image.
Active Region 1461 is that tiny sunspot a bit more than halfway from the center at the 10:00 position (it has rotated away from the limb of the Sun since April 16).
So what is coronal rain? Sunspots are active regions that periodically emit coronal mass ejections (CMEs) of plasma - charged particles over 100,000° F (the details are complicated and the subject of another post). The strong gravitational field of the Sun pulls this plasma back down to the surface but since it's composed of charged particles, they follow magnetic lines of force which form loops about the sunspots. Falling blobs of plasma (many larger than the Earth) fall back into the Sun looking like rain.
The Sun has been fairly active lately and studded with sunspots. Here's today's solar image.
Active Region 1461 is that tiny sunspot a bit more than halfway from the center at the 10:00 position (it has rotated away from the limb of the Sun since April 16).
So what is coronal rain? Sunspots are active regions that periodically emit coronal mass ejections (CMEs) of plasma - charged particles over 100,000° F (the details are complicated and the subject of another post). The strong gravitational field of the Sun pulls this plasma back down to the surface but since it's composed of charged particles, they follow magnetic lines of force which form loops about the sunspots. Falling blobs of plasma (many larger than the Earth) fall back into the Sun looking like rain.
Thursday, April 19, 2012
RIP Levon
Woodstock resident and legendary musician Levon Helm (1940-2012) died today.
And just because I like this song (the cornfield on this album cover is Gill Farms, just up the road from my house).
Listening to WDST playing Levon Helm songs tonight.
Levon's on right on drums with Ringo, Dylan, Van Morrison,
Neil Diamond, Dr. John, Rich Danko, and others (1976)
A happy man playing the drums
Listening to WDST playing Levon Helm songs tonight.
Tuesday, April 17, 2012
Utterly insignificant
So, today was my birthday. I hate, nay despise birthdays. Just another year closer to death. At least it wasn't as bad as last year's birthday. Still depressed as hell.
Would you like to feel insignificant too? Click on the image below to view a pan-and-zoomable image of a portion of our Milky Way galaxy. The image contains a billion stars. Did you hear me? A billion (with a "b") fucking stars.
Phil Plait over at Bad Astronomy wrote about this image as well. What's so special about our galaxy among the hundreds of billions of galaxies in the universe? Nothing. What's so special about our star among the hundreds of billions of stars in our galaxy. Nothing. What's so special about me among the billions of people who've ever lived on Earth? Nothing.
On the scale of the universe, we are completely and utterly insignificant. Sweet dreams.
Would you like to feel insignificant too? Click on the image below to view a pan-and-zoomable image of a portion of our Milky Way galaxy. The image contains a billion stars. Did you hear me? A billion (with a "b") fucking stars.
Phil Plait over at Bad Astronomy wrote about this image as well. What's so special about our galaxy among the hundreds of billions of galaxies in the universe? Nothing. What's so special about our star among the hundreds of billions of stars in our galaxy. Nothing. What's so special about me among the billions of people who've ever lived on Earth? Nothing.
On the scale of the universe, we are completely and utterly insignificant. Sweet dreams.
Friday, April 13, 2012
Mohonk Climate Change Lecture
Shanon Smiley, a conservation biologist with the Mohonk Preserve, will be discussing the 100+ years of weather records from the Mohonk Mountain House on the Shawangunk Ridge.
Please feel free to print and distribute this flyer. The lecture is Thursday, April 26 in the College Student Lounge on the SUNY Ulster main campus at 7:30 pm. It's free and open to all.
Thursday, April 12, 2012
The Size of the Sun
How big does the Sun appear in the sky from the surface of the Earth? You can look it up, the angular diameter of the Sun is 0.5°, but it's also very easy to calculate. In the figure below, D represents the true diameter of the Sun (1.392 x 106 km) and d represents the distance from the Earth to the Sun (149,598,261 km). The radius of the Sun (r) will be half of D (r = D/2). Delta (d) is the angular diameter of the Sun from the distance of the Earth and alpha (a) is half of this (a = d/2).
Since d and r form two legs of a right triangle, simple trigonometry will tell us that the sine of the angle a is r / d.
sin(a) = (r/d)
Substituting (r = D/2) and (a = d/2) gives us:
sin(d/2) = [(D/2)/d]
or
d = 2 sin-1 [(D/2)/d]
Therefore, for the Sun, we can calculate its angular diameter as:
d = 2 sin-1 [(1.392 x 106 km/2)/149,598,261 km] = 0.533° (half a degree)
OK, we know that. But we can use this same procedure to calculate the angular diameter of the Sun from each of the other 7 major planets in our solar system. All we need to do is look up their average distance from the Sun which we can do easily enough.
Mercury d = 2 sin-1 [(1.392 x 106 km/2)/57,910,000 km] = 1.4°
Venus d = 2 sin-1 [(1.392 x 106 km/2)/108,200,000 km] = 0.74°
Mars d = 2 sin-1 [(1.392 x 106 km/2)/227,940,000 km] = 0.35°
Jupiter d = 2 sin-1 [(1.392 x 106 km/2)/778,330,000 km] = 0.10°
Saturn d = 2 sin-1 [(1.392 x 106 km/2)/1,429,400,000 km] = 0.06°
Uranus d = 2 sin-1 [(1.392 x 106 km/2)/2,870,990,000 km] = 0.03°
Neptune d = 2 sin-1 [(1.392 x 106 km/2)/4,504,000,000 km] = 0.02°
How does this look diagrammatically?
The Sun would look a bit smaller in the Martian sky and a bit larger in the Venusian sky. The Sun from Mercury would be frighteningly large (and fry you with temperatures around 800° F). The Sun is much smaller from the outer gas giant planets since they're so much further from the Sun than the inner rocky planets. It would be much brighter than any of the other stars in the sky, but not much larger.
Another interesting tidbit. The Moon has a diameter of 3476 km and is 384,400 km from Earth. Plugging these values into the above equation gives:
Moon d = 2 sin-1 [( 3476 km/2)/384,400 km] = 0.52°
So, even though the Moon is much, much smaller than the Sun, it's also much, much closer and looks about the same size in our sky (half a degree). That's why solar eclipses are possible - the Moon can block our view of the Sun given a favorable orbital geometry.
Trigonometry is cool.
Wednesday, April 11, 2012
Hypnotic wind map
Check out this almost real-time animated wind map.
Go to the website (http://hint.fm/wind/index.html), watch it for a bit, and then zoom in. Unbelievable. Then compare it to the daily weather map of highs, lows, and fronts (http://cache1.intelliweather.net/imagery/IntelliWeather/fcmap12hour_nat_640x480.jpg).
Winds flow from high to low pressure areas and stream parallel to the frontal boundaries. Awesome.
Go to the website (http://hint.fm/wind/index.html), watch it for a bit, and then zoom in. Unbelievable. Then compare it to the daily weather map of highs, lows, and fronts (http://cache1.intelliweather.net/imagery/IntelliWeather/fcmap12hour_nat_640x480.jpg).
Winds flow from high to low pressure areas and stream parallel to the frontal boundaries. Awesome.
Tuesday, April 10, 2012
WTF - Dinosaurs in Eden
Saw some pictures recently from a book by Ken Ham called Dinosaurs of Eden: Tracing the Mystery Through History (2000, Master Books). Ham, for those who don't know, is the President/CEO of Answers in Genesis, the young-Earth creationist organization that runs the Creation Museum in Petersburg, Kentucky.
Young-Earth creationists (YECs) believe that God created the world around 6,000 years ago exactly as described in the book of Genesis. Since creation took place in six 24-hour days (on the 7th day, God rested), they are forced to conclude that dinosaurs were roaming around with Adam and Eve in the Garden of Eden.
They are also forced to conclude, since the world was perfect with no pain, suffering, and death before the Fall, that dinosaurs like T. rex ate coconuts or something with those long, serrated teeth. They also debate whether or not Noah took dinosaurs on the ark (yes, it is surreal, some seriously propose they only took baby dinosaurs since space was at a premium).
By the way, I saw Ken Ham speak once, a long time ago now, when I was a graduate student at the University of Illinois at Urbana-Champaign. Everything he said about geology in that talk (which was given in a church) was a complete lie (I'm not going to be charitable and assume he was just ignorant, because he's not a dumb man - he's a lying sack of shit who lives better than I off the donations of others and outright slanders science and scientists).
Anyhow, here are the pictures I saw posted from his book:
Young-Earth creationists (YECs) believe that God created the world around 6,000 years ago exactly as described in the book of Genesis. Since creation took place in six 24-hour days (on the 7th day, God rested), they are forced to conclude that dinosaurs were roaming around with Adam and Eve in the Garden of Eden.
They are also forced to conclude, since the world was perfect with no pain, suffering, and death before the Fall, that dinosaurs like T. rex ate coconuts or something with those long, serrated teeth. They also debate whether or not Noah took dinosaurs on the ark (yes, it is surreal, some seriously propose they only took baby dinosaurs since space was at a premium).
By the way, I saw Ken Ham speak once, a long time ago now, when I was a graduate student at the University of Illinois at Urbana-Champaign. Everything he said about geology in that talk (which was given in a church) was a complete lie (I'm not going to be charitable and assume he was just ignorant, because he's not a dumb man - he's a lying sack of shit who lives better than I off the donations of others and outright slanders science and scientists).
Anyhow, here are the pictures I saw posted from his book:
Those large claws on Deinonychus were presumably very useful for pulling branches down so he could eat oranges. And look, Adam has a pet monkey and Eve is feeding a pterosaur (Anurognathus). For an archetypical woman, Eve's a little homely, don't you think?
This next one's just silly.
I guess Ham believes dinosaurs did take a ride on Noah's ark since the text is talking about the time between Noah (Genesis 6) and the Tower of Babel (Genesis 11). Very clever of people at the time to domesticate the dinosaurs and use them as beasts of burden (quite the accomplishment - can you think of any domesticated reptiles today?).
It would be pretty neat to have a tame Gallimimus to saddle up and ride on - like a real live Dinotopia. Unfortunately, since the word "dinosaur" wasn't invented until the 1800s, the ancient Hebrews didn't know what to call them so they got left out of the Bible (maybe the word "camels" is a mistranslation - Jesus may really have said "Again I tell you, it is easier for an Tyrannosaurus to go through the eye of a needle than for someone who is rich to enter the kingdom of God.”
Why not? Makes about as much sense as anything Ken Ham has claimed.
Sunday, April 8, 2012
Easter Sunday and, yes, another hike
I've had a very productive long weekend, at least as far as hiking goes, with nice walks in the woods on Thursday, Friday, and Easter Sunday (Saturday I went to someone's last minute surprise wedding which was very nice too).
My daughter made me go to church with the family in the morning (she's the only one I'd do it for). I'm not the church-going type, I feel far more spiritual and aware of transcendence walking alone through a sun-dappled hemlock forest than I do sitting in a pew. The crows teach me more than any sermon I've heard. Yes, I'm a pagan.
Since we were going to me sister's for dinner later that day, and I knew I would overeat, I decided a hike was what I needed after church and went for another 6 mile walk on the Shawangunk Ridge. Once again I was in a relatively isolated area of the Ridge (I took Undivided Lot trail to the end and returned on Laurel Ledge and Stokes trail if anyone is familiar with the area). Even though it was a holiday Sunday, I didn't see a single person the whole time.
I passed a trail to a place called Zaidee's Bower which is somewhere I haven't gone to but really would like to visit. Problem is that I'm usually in that area by myself and the trail is described as having "...some very tight squeezes and requires the ability to support your weight with your upper body." Not a problem for me but given that if I got in trouble there it would be days before anyone found me (especially since I rarely tell people where I'm going when leaving the house). My family doesn't like hiking as much as I do (and wouldn't want to go here since it's a few miles and few hundred feet elevation gain from any trailheads) so I'll have to find someone else accompany me to this place.
Here are some pretty flowers I saw (my flower field guide sucks so I once again have no idea what these are).
I also saw a very nice mourning cloak butterfly (Nymphalis antiopa).
My daughter made me go to church with the family in the morning (she's the only one I'd do it for). I'm not the church-going type, I feel far more spiritual and aware of transcendence walking alone through a sun-dappled hemlock forest than I do sitting in a pew. The crows teach me more than any sermon I've heard. Yes, I'm a pagan.
Since we were going to me sister's for dinner later that day, and I knew I would overeat, I decided a hike was what I needed after church and went for another 6 mile walk on the Shawangunk Ridge. Once again I was in a relatively isolated area of the Ridge (I took Undivided Lot trail to the end and returned on Laurel Ledge and Stokes trail if anyone is familiar with the area). Even though it was a holiday Sunday, I didn't see a single person the whole time.
Undivided Lot Trail near Old Minnewaska Trail
I passed a trail to a place called Zaidee's Bower which is somewhere I haven't gone to but really would like to visit. Problem is that I'm usually in that area by myself and the trail is described as having "...some very tight squeezes and requires the ability to support your weight with your upper body." Not a problem for me but given that if I got in trouble there it would be days before anyone found me (especially since I rarely tell people where I'm going when leaving the house). My family doesn't like hiking as much as I do (and wouldn't want to go here since it's a few miles and few hundred feet elevation gain from any trailheads) so I'll have to find someone else accompany me to this place.
How long until they find my body if I slipped and fell down this crevice?
Here's my question for the day. Why does some dead wood turn green? Not as clear in this photo as it is in real life, but this stick (birch?) was a deep blue-green color - almost the color of oxidized copper.
I also saw a very nice mourning cloak butterfly (Nymphalis antiopa).
Tomorrow it's back to work where I have to deal with two different student issues. Can't wait.
Saturday, April 7, 2012
Watch, what watch?
Saw this story at P.Z. Myers Pharyngula blog on Who needs a $30,000 watch? Unbelievable. Also pretty funny when you look at the two images and see that while they Photoshopped the watch out of the second image, they forgot to Photoshop out the watch's reflection in the table!
I totally agree with Myers, by the way. I think anyone who would spend $30K on a watch is a narcissistic moron (not that I'd even recognize a $30,000 watch on someone's wrist). I'd trust a godless atheist like Myers with my money far more than most religious leaders.
I totally agree with Myers, by the way. I think anyone who would spend $30K on a watch is a narcissistic moron (not that I'd even recognize a $30,000 watch on someone's wrist). I'd trust a godless atheist like Myers with my money far more than most religious leaders.
Friday, April 6, 2012
Friday Hike
Went for another hike today. Back to the Mohonk Preserve (I have a membership so I hike there a lot). When I was leaving, my wife asked me where I was going and I didn't know. A lot of times I'll leave to go on a hike and not know exactly where I'm going. I've often decided while driving which trailhead I'll park at. Then, at the trailhead, I'll figure out my final destination just by starting to walk in some direction as the spirit moves me.
Today I parked at the Spring Farm trailhead and followed Table Rock trail. Spotted a neat little plant I know called hepatica (Hepatica nobilis). The name comes from the Greek word for liver because the leaf has three lobes like the human liver. It's a traditional medicinal plant, once thought to be good for the liver due to its shape (the Medieval "doctrine of signatures").
The trail passes through a beautiful meadow, still mostly brown but soon to be filled with grasses and blooming with wildflowers. I love this meadow sitting surrounded by woods. The picture doesn't do it justice. I was walking through the meadow, the warm Sun is shining, the sky is deep blue, the grasshoppers are buzzing, and the birds are singing. I can't even describe how places like this make me feel.
I continued along the trail to a junction. As I was wondering which way to go, I heard a barred owl calling to my right. That decided my direction.
Some wildflowers along the trail. I have a book called Wildflowers of New York but couldn't identify either of these from pictures (of course, I didn't note down details of the leaves and stems and things). Feel free to enlighten me if you know what they are.
Today I parked at the Spring Farm trailhead and followed Table Rock trail. Spotted a neat little plant I know called hepatica (Hepatica nobilis). The name comes from the Greek word for liver because the leaf has three lobes like the human liver. It's a traditional medicinal plant, once thought to be good for the liver due to its shape (the Medieval "doctrine of signatures").
The trail passes through a beautiful meadow, still mostly brown but soon to be filled with grasses and blooming with wildflowers. I love this meadow sitting surrounded by woods. The picture doesn't do it justice. I was walking through the meadow, the warm Sun is shining, the sky is deep blue, the grasshoppers are buzzing, and the birds are singing. I can't even describe how places like this make me feel.
I continued along the trail to a junction. As I was wondering which way to go, I heard a barred owl calling to my right. That decided my direction.
Some wildflowers along the trail. I have a book called Wildflowers of New York but couldn't identify either of these from pictures (of course, I didn't note down details of the leaves and stems and things). Feel free to enlighten me if you know what they are.
I also saw these plants. They were growing in a moist area. At first I thought they were skunk cabbage but the leaves are different. Anyone know?
And here, for no apparent reason, is a picture of a bumblebee drinking water. I thought it was cool and watched him (her?) for a while.
I also came across some coyote scat. How do I know it's coyote? It was displayed prominantly on top of a rock, looks like dog poop, but is loaded with fur and bones (the white bone in the crushed up piece looks like a little rodent scapula).
This may be why people don't generally go hiking with me. I take pictures of shit.
Anyway, I followed a little-used trail I like (since I never run into people on it) and ended up at Bonticou Crag, one of my favorite places on the Ridge. There's a great "trail" to the top that goes up the front face winding it's way among the talus boulders (Click on the picture to make it larger. See the guy in the red sweatshirt near the top? That's the trail).
Here's a view from near the top looking down (I actually came down that way today).
The most challenging part of the climb is near the top when you have to shimmy up a crevice and then climb along a very exposed ledge for a short distance (not for those afraid of heights). The crevice, like many along the ridge, is actually a strike-slip fault (can't have a post without a little geology).
One of these days I'll write about Bonticou. It's a sacred place.
Thursday, April 5, 2012
Thursday Hike
Since I had off today (our school had today scheduled as a makeup day which we didn't need to use since we've had few snow days this winter), I decided to go for a hike. It was a beautiful day around 60 F.
For those who know the Mohonk Preserve, I started at Clove Chapel, went up Undivided Lot Trail to Stokes Trail to Maple Path to Laurel Ledge Road to Cope's Lookout. It's a couple of miles and about 1,000 feet of elevation gain. On the return, I went down Cathedral Path to Laurel Ledge Path to Clove Path and back to Undivided Lot Trail. It was a nice hike and Undivided Lot Trail is one of the more remote areas of the Preserve (which I like since I rarely run into people).
Going to the gym three times a week since last September has paid off. I'm definitely hiking better than I was last summer - especially on the uphill segments.
Signs of spring abounded in the woods. Here are some fiddleheads poking up through the dead leaves.
These little pinkish flowers are on blueberry bushes.
A flowering tree.
I don't know offhand what the tree is, but here's a slightly blurry closeup of the flower.
And, since I'm a geologist, here's a nice example of physical weathering as the rock breaks down along bedding planes and vertical joint sets.
And who can resist a nice set of chatter marks and glacial striations.
For those who know the Mohonk Preserve, I started at Clove Chapel, went up Undivided Lot Trail to Stokes Trail to Maple Path to Laurel Ledge Road to Cope's Lookout. It's a couple of miles and about 1,000 feet of elevation gain. On the return, I went down Cathedral Path to Laurel Ledge Path to Clove Path and back to Undivided Lot Trail. It was a nice hike and Undivided Lot Trail is one of the more remote areas of the Preserve (which I like since I rarely run into people).
Going to the gym three times a week since last September has paid off. I'm definitely hiking better than I was last summer - especially on the uphill segments.
Signs of spring abounded in the woods. Here are some fiddleheads poking up through the dead leaves.
These little pinkish flowers are on blueberry bushes.
A flowering tree.
I don't know offhand what the tree is, but here's a slightly blurry closeup of the flower.
And, since I'm a geologist, here's a nice example of physical weathering as the rock breaks down along bedding planes and vertical joint sets.
And who can resist a nice set of chatter marks and glacial striations.
And some fault striations on the side of a crevice.
Here's a scenic view of Cope's Lookout. The cliffs on the left are the Trapps - a world-class rock climbing destination. The valley on the right is Clove Valley and, geologically, a syncline where the Shawangunk Conglomerate bedrock downwarps into a trough.
Here's how I like to eat lunch - sitting on a cliff with my feet dangling off.
I'll close with a self-portrait...
Wednesday, April 4, 2012
Mercury's Gold
One of the aims of classical alchemists was figuring out a way to turn base metals into precious metals, often using the liquid metal mercury in their processes. Ultimately, it was a fool's quest (although they did discover a lot about chemistry in the process). This is my clever way to introduce a post about fool's gold and Mercury.
A week or so ago, March 19-23. the Lunar and Planetary Science Conference (LPSC) was held in Houston, Texas. A few of the papers presented caught my eye since I'm teaching a course on Solar System Astronomy this semester.
A group of researchers presented a paper titled Mercury's Internal Structure as Constrained by Messenger Observations where they discussed some of the most recent findings from NASA's MESSENGER probe which is currently orbiting and studying the planet Mercury.
The Earth, for example, has an internal structure composed of an iron core, a mantle, and the crust. The crust is, of course, solid. Many people mistakenly believe the mantle of the Earth is molten magma but it's also solid. It's properties change with depth, due to pressure and temperature changes, but it's primarily plastic. This means it's soft and flows while remaining solid (I illustrate this in my class with Silly Putty).
The core is segregated into two parts - an inner solid core surrounded by an outer liquid core. As the Earth cools over geologic time spans, the core is gradually solidifying. The movements of liquid iron in the Earth's outer core, by the way, generates the Earth's magnetic field.
Mercury also has a core, mantle, and crust but the core is much larger proportionally than we would expect. Mercury may once been much larger but lost much of its outer core and mantle from a large collision (there is a lot of indirect evidence on other planets and moons for the occurrence large collisions early in the history of our solar system).
By analyzing the rotation of Mercury on its axis, planetary scientists are able to determine that the solid outer crust and mantle of the planet is decoupled from a solid core by a liquid layer. This is interpreted to mean that the outer part of Mercury's iron core is still liquid. Mercury does have a magnetic field as well.
The MESSENGER spacecraft has been making some detailed measurements of Mercury's gravity field and this data, along with geochemical data obtained from analysis of surface rocks on the planet, allows planetary scientists to develop models of the interior of the planet (see the paper for all the messy mathematical details).
One model leads to the possibility that there is a layer of solid iron sulfide (FeS2) at the core-mantle boundary. This is the mineral pyrite, also known as "fool's gold" (you would be a real fool to confuse it with gold because it has very different physical properties), and relatively common here on Earth.
A week or so ago, March 19-23. the Lunar and Planetary Science Conference (LPSC) was held in Houston, Texas. A few of the papers presented caught my eye since I'm teaching a course on Solar System Astronomy this semester.
A group of researchers presented a paper titled Mercury's Internal Structure as Constrained by Messenger Observations where they discussed some of the most recent findings from NASA's MESSENGER probe which is currently orbiting and studying the planet Mercury.
Since we know how large Mercury is (mean radius = 2.4397 x 108 cm) and we can accurately determine its mass from its orbital characteristics (3.3022×1026 g), we can calculate its bulk density (r) which is mass per unit volume.
[The radius and mass values I used are from Wikipedia. The radius was multiplied by 100,000 to convert kilometers to centimeters and mass was multiplied by 1,000 to convert kilograms to grams.]
[The radius and mass values I used are from Wikipedia. The radius was multiplied by 100,000 to convert kilometers to centimeters and mass was multiplied by 1,000 to convert kilograms to grams.]
r = 3.3022×1026 g / (6.0827 x 1025 cm3)
r = 5.43 g/cm3
OK, so what? Well it turns out that this is an anomalously high density for such a small planet. The average density of crustal rocks is around 2.7 g/cm3. This means that the interior of Mercury has to be much more dense. Since, for a variety of reasons, we know that terrestrial planets have internal cores composed primarily of iron, the size of this iron core can then be calculated.
The Earth, for example, has an internal structure composed of an iron core, a mantle, and the crust. The crust is, of course, solid. Many people mistakenly believe the mantle of the Earth is molten magma but it's also solid. It's properties change with depth, due to pressure and temperature changes, but it's primarily plastic. This means it's soft and flows while remaining solid (I illustrate this in my class with Silly Putty).
The core is segregated into two parts - an inner solid core surrounded by an outer liquid core. As the Earth cools over geologic time spans, the core is gradually solidifying. The movements of liquid iron in the Earth's outer core, by the way, generates the Earth's magnetic field.
Mercury also has a core, mantle, and crust but the core is much larger proportionally than we would expect. Mercury may once been much larger but lost much of its outer core and mantle from a large collision (there is a lot of indirect evidence on other planets and moons for the occurrence large collisions early in the history of our solar system).
By analyzing the rotation of Mercury on its axis, planetary scientists are able to determine that the solid outer crust and mantle of the planet is decoupled from a solid core by a liquid layer. This is interpreted to mean that the outer part of Mercury's iron core is still liquid. Mercury does have a magnetic field as well.
The MESSENGER spacecraft has been making some detailed measurements of Mercury's gravity field and this data, along with geochemical data obtained from analysis of surface rocks on the planet, allows planetary scientists to develop models of the interior of the planet (see the paper for all the messy mathematical details).
One model leads to the possibility that there is a layer of solid iron sulfide (FeS2) at the core-mantle boundary. This is the mineral pyrite, also known as "fool's gold" (you would be a real fool to confuse it with gold because it has very different physical properties), and relatively common here on Earth.
Pyrite's a beautiful mineral, often forming golden cubic crystals. It's neat to imagine the interior of a planet has a layer of this stuff. It's also neat to see how astronomers can figure out what's in the interior of a planet without ever stepping foot on it. Science rocks!
Sunday, April 1, 2012
Sunday ramblings...
So I was reading my monthly horoscope for the upcoming month and learned the following:
The Sun continues to shine its light on your solar twelfth house. This is the time to listen to your intuition, to take a break from the hectic pace of your life, and to reflect on what you have learned in the past year. You might naturally retreat a little and take more private time for yourself now.
That frightened me a bit, since my intuition is that I need a break. I thought I might drive out to the Creation Museum in Petersburg, Kentucky (just south of Cincinnati). I'll call in sick at work for the next couple of weeks and ask my colleagues to show my students videos while I'm off - here's a good one for my historical geology class. I've been coming more and more skeptical of evilution now that I see how scientists are simply unable to address objections to Darwinism proposed by great thinkers like Ken Ham.
Has anyone noticed the Moon looks funny lately too? Tilted weirdly. I think the scientists are covering it up to avoid panic.
I can't believe I didn't win the MegaMillions lottery either. I bought $1,000 worth of tickets because I know how your odds are greatly improved when you buy more tickets like that. I even used my lucky numbers that I got out of a Chinese take-out fortune cookie last Friday
By the way, did you see the Washington Post OpEd which exposed how college professors don't work hard enough? As a professor I can certainly attest to that. I only teach a few hours a week. I don't have to come in until 11 am and typically leave before 2 pm when I go down to the local tavern and drink Scotch until it's time for dinner. Top shelf stuff too since I'm paid so well as a full professor.
Since I have so much free time, I've decided to get invest in other activities to keep from getting bored. Did you know they used to mine silver and gold right here in the Shawangunks? True. I was doing some historical research and came across some documents in the local historical society archives that have been completely overlooked. As a geologist, I was able to figure out the exact locations referred to and hiked out there one day after I gave my students a worksheet and left class early. There's still enough gold in some of these mines to make a whole slew of people fabulously wealthy. I was able to purchase some of the land these mines are on from the Mohonk Preserve and am currently selling shares in the mine to those people who aren't afraid of being rich. At only $1,000 / share, it's a great opportunity. Just mail me a check and you're in.
Oh, some good news for a change. My wife has finally agreed that an open marriage would do us a world of good. So, if you're an attractive female between the ages of 18 and 30 (35 if you take care of yourself), give me a ring. Sorry, but current students are not eligible for this offer. Not to be immodest, but I do have quite the reputation as a ladies man. You know what they say about geologists, right? We know how to make the bedrock!
On a final, more serious note. The recent uptick in solar flare activity on the Sun leads me to caution everyone reading my blog. Energetic particles from large coronal mass ejections (CMEs) can damage sensitive brain tissue unless you take precautions. Fortunately, there is an easy, inexpensive remedies everyone has available in their kitchens. A layer of aluminum foil (heavy duty) will very effectively shield you from these particles (as long as you point the top of your head toward the Sun during a CME. Here are some simple directions (by the way, it's aluminum foil, not tin foil!).
You did notice the date this was posted, right?
The Sun continues to shine its light on your solar twelfth house. This is the time to listen to your intuition, to take a break from the hectic pace of your life, and to reflect on what you have learned in the past year. You might naturally retreat a little and take more private time for yourself now.
That frightened me a bit, since my intuition is that I need a break. I thought I might drive out to the Creation Museum in Petersburg, Kentucky (just south of Cincinnati). I'll call in sick at work for the next couple of weeks and ask my colleagues to show my students videos while I'm off - here's a good one for my historical geology class. I've been coming more and more skeptical of evilution now that I see how scientists are simply unable to address objections to Darwinism proposed by great thinkers like Ken Ham.
Has anyone noticed the Moon looks funny lately too? Tilted weirdly. I think the scientists are covering it up to avoid panic.
I can't believe I didn't win the MegaMillions lottery either. I bought $1,000 worth of tickets because I know how your odds are greatly improved when you buy more tickets like that. I even used my lucky numbers that I got out of a Chinese take-out fortune cookie last Friday
By the way, did you see the Washington Post OpEd which exposed how college professors don't work hard enough? As a professor I can certainly attest to that. I only teach a few hours a week. I don't have to come in until 11 am and typically leave before 2 pm when I go down to the local tavern and drink Scotch until it's time for dinner. Top shelf stuff too since I'm paid so well as a full professor.
Since I have so much free time, I've decided to get invest in other activities to keep from getting bored. Did you know they used to mine silver and gold right here in the Shawangunks? True. I was doing some historical research and came across some documents in the local historical society archives that have been completely overlooked. As a geologist, I was able to figure out the exact locations referred to and hiked out there one day after I gave my students a worksheet and left class early. There's still enough gold in some of these mines to make a whole slew of people fabulously wealthy. I was able to purchase some of the land these mines are on from the Mohonk Preserve and am currently selling shares in the mine to those people who aren't afraid of being rich. At only $1,000 / share, it's a great opportunity. Just mail me a check and you're in.
Oh, some good news for a change. My wife has finally agreed that an open marriage would do us a world of good. So, if you're an attractive female between the ages of 18 and 30 (35 if you take care of yourself), give me a ring. Sorry, but current students are not eligible for this offer. Not to be immodest, but I do have quite the reputation as a ladies man. You know what they say about geologists, right? We know how to make the bedrock!
On a final, more serious note. The recent uptick in solar flare activity on the Sun leads me to caution everyone reading my blog. Energetic particles from large coronal mass ejections (CMEs) can damage sensitive brain tissue unless you take precautions. Fortunately, there is an easy, inexpensive remedies everyone has available in their kitchens. A layer of aluminum foil (heavy duty) will very effectively shield you from these particles (as long as you point the top of your head toward the Sun during a CME. Here are some simple directions (by the way, it's aluminum foil, not tin foil!).
You did notice the date this was posted, right?