free debate

August 29, 2009

It's Nessie on Google Earth!!! (or is that a boat?)

People love to find cool stuff. That's part of what drives scientists around the world. However, sometimes this drive can lead us to find nonsense. Similarly, Google Earth is a great computer program, but it too can be used to find nonsense.

If you remember a few months back, someone claimed to have found Atlantis on Google Earth. That turned out to be an artifact of how Google put together the data. Now Fox News is reporting that Nessie has been found using Google Earth.

I have written about how credulous the news can be and this is a perfect example. Fox says "Some experts believe Nessie may be a Plesiosaur, an extinct marine reptile with a shape like the Google image." Who ever these "experts" are, they have a very poor knowledge of Plesiosaurs. To me, this image looks more like a squid than a Plesiosaur.

In actuality, of course, you are seeing a boat. The tentacles or fins are really just wakes. In fact if you look at pretty much any popular lake in the world with Google Earth you can find similar images. The one below is from lake Powell. You can see how every boat has a slightly different wake pattern. The is a great example of pareidolia at work.

To see this for yourself, you can go to Latitude 57°12'52.13"N, Longitude 4°34'14.16"W on Google Earth.

August 27, 2009

Lightning's Twin

And here I thought normal lightning was cool.

As it turns out, lightning has a twin above the clouds. It's known as a gigantic jet. The name is pretty accurate, too; where normal lightning fits into a 6-inch channel and travels up to around 4.5 miles, gigantic jets have multiple channels and can travel as much as 40 miles, and enter the ionosphere (which is the boundary between the atmosphere and outer space).

Because of their location, and their short duration, there are only 5 photographs of these gigantic jets. One of the most recent of these was caught nearly on accident. Steven Cummer, of Duke University in North Carolina, had equipment set up to photograph sprites, another sort of electrical discharge in the upper atmosphere. Their equipment was in just the right place at the right time, to capture a 1 second image of a gigantic jet.

This new data will be very useful as scientists study these gigantic jets more closely. Right now, very little is known about them. Scientists have no idea what types of storms or conditions are necessary to produce a gigantic jet. Cummer is planning to set up a high-speed, low-light, color camera, to attempt to capture more images of this upward lightning. This will help determine chemical process, temperature, discharge patterns, and much more. For now, we have a couple cool pictures and videos, and hopefully more are on the way.

Credit: Science Daily- Lightning's Mirror Image... Only Much Bigger

August 26, 2009

Dynamic Earth: Earthquakes

With a whole bunch of solid plates moving about on the Earth's surface, via plate tectonics, it isn't surprising that natural disasters often occur around plate boundaries. Earthquakes, in particular, are related to plate tectonics.

The boundary between two plates is a fault zone, and it is in these zones that earthquakes typically occur. There is a huge amount of friction that builds up on these fault lines, as the plates move against each other. The tension has to be released at some point, causing an earthquake (see image to right). To see what this is like, try this little experiment. Press your hands together tightly. Now, try to slide one forward. It is difficult to move, at first. At some point, though, your hand shoots out, as the pressure created by your arm is greater than the friction between your hands. This is exactly what happens on a fault line.

A prime example of a fault would be the San Andreas Fault, in California. This fault marks the boundary between the North American and Pacific plates. There has been tension building up in a section of this fault, near Los Angeles, for around 300 years. Because of this, it is possible that a newly discovered type of earthquake will hit is area, and soon. Supershear earthquakes are the geological equivalent of a sonic boom. They travel much faster than seismic waves were thought to be able to. They could be devastating, if they hit major cities like LA or San Francisco.

There is a lot more to earthquakes, and I'll try to elaborate further in another post. For now, though, check out TheTech for more about earthquakes in general.

Credit to New Scientist for information of supershear earthquakes, and to the TV show How the Earth Was Made.

August 25, 2009

A Spacecraft Anomaly and an Amazing Picture

LCROSS (the Lunar Crater Observation and Sensing Satellite) is part of NASA's plan to return to the moon.  LCROSS is a low-cost, high-risk mission.  That risk, however, was not supposed to be until October.

On August 22nd, LCROSS started experiencing an "anomaly."  According to NASA, a fault in one of the instruments used to determine its orientation caused the thrusters to fire excessively.  Mission operations declared a "spacecraft emergency" and are still working to mitigate the problem.  One of the major problems is the large amount of fuel LCROSS consumed durring the anomaly.  The team is still trying to figure out what went wrong to try and prevent it from happening again.

I really hope that NASA can get this figured out soon.  The main objective of LCROSS is to crash into the surface of the moon and send up a plume of material.  As of right now, NASA is saying that they will have enough fuel for everything to continue as planned.  The plan now is to impact the moon in the early morning of Oct. 9th.  Don't be surprised if this date changes and I will keep you updated on opportunities to view this amazing event.

The image at the top is an image taken by LCROSS of the moon and the Earth both as crescents.  The Earth is in the foreground and the blue/red specs are cosmic radiation (not stars).

Image Credit NASA Ames

August 22, 2009

A New Face to Saturn's Rings

Over the last few months, we have been treated to a series of images of long shadows cast across Saturn's rings.  This unique viewing opportunity happens about every 15 years as Saturn approaches equinox.  The low angle of the Sun's rays across the rings has been great for science and, of course, produced some amazing photos.  August 11th was Saturn's equinox, so now the opposite side of the rings is being lit up by the sun.

In this bottom image you can see Titan and the shadow that it's casting on the planet.  Both of these are raw images from Cassini so they're a little rough but still give a sense for Saturn's grandeur.  Click on the images to a larger version.

In my opinion, Cassini has produced more eye candy than any other spacecraft we have put up there.  I hope that Cassini will continue to function for many more years before it is crashed into Saturn.  Imagine what we would see and learn if we sent a Cassini-like mission to each of the outer planets.  I hope the folks at NASA recognize the public interest these images have produced and will try for more missions that will be able to capture the majesty that space has to offer.

All images are credit NASA/JPL/Space Science Institute

August 21, 2009

Celebrating 100 Years: The Burgess Shale

One of the absolute coolest fossil sites is the Burgess Shale, located near Field, British Columbia. The formation was discovered almost exactly 100 years ago, by paleontologist Charles Walcott of the Smithsonian. In it are preserved the remains of the ocean life from over 500 million years ago, during the Cambrian period.

What is so interesting about the Burgess Shale is the incredible quality of the fossils. In general, fossils are remains of hard tissue: bones, shells, exoskeletons, teeth, and so on. The Burgess Shale fossils show soft tissue as well. Paleontologists find structures like eyes, and even whole organisms that didn't have hard parts at all. It's also one of the most productive fossil sites; there are a huge number of fossils coming out of a relatively small area.

Another neat feature of this fossil deposit is that it spans a time of rapid evolution. Between 542 and 488 million years ago, so many diverse forms of life developed that that time period is called the Cambrian Explosion. Many of these forms are bizarre, as well. There are spiny worms, 5 eyed arthropods with elephant trunks, and something that looks like a combination of jellyfish, sea cucumber, shrimp, and snail. And these are just a few of the sea creatures that roamed the ancient sea of the Cambrian. It is these forms, and the implications they have on how life developed, that make the Burgess Shale such an important, and amazingly cool, formation.

Credit: American Institute of Physics

August 20, 2009

What is Skepticism?

Science is a process. We use this process the understand the natural world around us.  There is a growing group of people who use this process to form their opinions about the world.  Skeptics promote critical thinking and science education.  Skeptics do not just dismiss ideas out of hand, but try to establish if an idea is supported by the evidence.  Skepticism is not a set of beliefs, but a method.  There are issues that multiple reasonable skeptics will hold different opinions on.
Skeptics often rely on the scientific method because it is one that relies on evidence and logic.  In science, anecdotal evidence is below the standard of evidence. This is one of the main reasons that skeptics can often get branded as deniers.  Skeptics will often reject ideas like UFOs and ghosts because the evidence does not support them.  This, however, can lead to the false conclusion that skeptics are close-minded.
Skeptics, as a group, have to remain open-minded.  To be close-minded is to hold a set of beliefs regardless of new evidence.  The evidence we have about the world around us always changing.  Since skepticism is based on evidence, our stances on different issues have to change.
Skepticism is a powerful tool for exploring reality. There are many cases where a dose of skepticism can really help in everyday life.  Skepticism is a way to keep an open mind and still be able to filter out the nonsense. 

August 19, 2009

Scientific Unknowns: What is Life?

Life is you, me, and every living thing on our planet, but defining it nearly impossible.  We study life here on Earth and look for it on distant worlds, so how can we not know what it is?  The real problem is we only have one example of life: our planet.

All life on Earth is based on the same things.  Carbon makes up the organic molecules; think of these as the Lego set of life.  DNA is the code that allows for replication and therefore evolution.  Water is the liquid that allows the organics to easily form long chains.  All of these things have come together to make life here on Earth.  What we don't know is if life could be based on other things, for example, liquid methane instead of liquid water.

Imagine that you had to define what a dog is, with only a St. Bernard as your example.  A St. Bernard has four legs, slobbers all over, is very resilient to the cold, has a long snout, and is usually very friendly.  By making a definition of all dogs by one breed, your definition becomes biased towards that breed.  Some things like having four legs will apply to all dogs, but when you try to pin down specific attributes your definition breaks down fast.

So, what parts of our definition of life apply across the board, and when are we being too specific?  We don't know.  This is maybe one of the most important questions in science, because it directly relates to how we look for other forms of life in the universe.  Could life be based on something other than carbon, maybe sulfur or silicon?  Is there a code other than DNA that life on a distant world has utilized?  The universe has always found ways of surprising us wherever we look.  I see no reason why the search for life would be any different.

August 17, 2009

The Wonder of Science

The night sky is a beautiful thing. I don't think I will ever get tired of seeing the Milky Way, or a meteor flash across the sky. Even the simple twinkle of a star. Yes, we live in an amazing universe. I think so many undervalue the beauty of nature, because they haven't been shown its complexity. Science is a method of describing reality. The reality of the universe, our universe, is one of unimaginable wonder and splendor.

I think that by destroying the quality of science education, we create the perfect storm for those who promote pseudoscience. We all want to think of our universe as a incredible place to live. I think that this is part of being human. If we starve a generation of the wonders of science, they will try to find it elsewhere. As much as the ideas of pseudoscientists may resonate within a person, it is the products of science that resonate with the world.

Science may not always give us the answer we want, but the answers we get are often stranger and more intricate then anyone would have ever guessed. We have never found evidence of Thor, but we have found black holes. Psychics have yet to show that they can see into the future, but scientists see billions of years into the past. We may not have found Bigfoot, but what of the dinosaurs that would make even a Yeti tremble? We have found particles that break all our common knowledge, and galaxies that break our sense of scale. No, the answers that science gives us are not always in line with what we want. The answers are rarely simple, and maybe not as comforting as we may like. Still, it is science in which I trust.

I write this now on the keyboard of my computer. As I do so, I draw electricity from my battery. That electricity was produced far from where I sit now, yet I am able to use it. You are able to read my words, because I have broadcast them through the air in a form of light invisible to my eyes. From there, the signal took advantage of cables, a work of art in and of themselves. I am sure before it ever reached you, it has been converted back and forth many times. It has done so while maintaining the quality necessary for you to be able to see these words in front of you. This is what science has done for us.

If somehow this does not impress you, think of this. If we were to live at almost any other point in history, we would not be able to come even close to feeding 6 billion people. Science makes this possible. Until very recently, people lived to a average age of 40. Now many of us expect to live to 80 or beyond. Science has changed the world in a way that I find unrivaled by any other human endeavor.

Today, I have watched the skies, but I have done so with friends. I have climbed mountains and looked out over amazing vistas. I have seen wonder in not only the eyes of a child, but in the eyes of high schoolers. I have met people whose lives I can only imagine. I have talked to the disabled, the elderly, and every other group I can think of. Regardless of who they were, or what they had done, there was something that they all shared. The curiosity and amazement I could see in them as they held a simple meteorite. It is amazing what a little rock from space can do.

This is why I explore the world. This is why I use science. The songwriter and comedian Tim Minchin said something in one of this poems that I think really sums up things very nicely. “Life is full of mysteries, yeah
, but there are answers out there
 and they won’t be found
 by people sitting around
 looking serious
 and saying 'Isn’t life mysterious?' ”

Bad Science: Pareidolia

There are many ways that we can come to believe in an idea.  Sometimes we even think that we are acting on evidence, when in reality that evidence is fallacious.  This Bad Science series is going to point out some common ways our brains can be tricked.

To start with, I have chosen one of my favorites: pareidolia.  Think of this as seeing familiar images in the clouds.  Our brains are really good at finding patterns.  That's why you can look at the bark of a tree or a rock formation and see a face.  Once you see that face, it may be hard not to see it.  This can make for a fun optical illusion.  The problem is when people think that the face in the clouds is real.

One of the best and most famous pieces of pareidolia is the face on Mars.  You can clearly see in this 1976 voyager picture a face in the rocks (left, near the top of the image).  The face is actually the product of shadows cast by the sun, poor resolution, and pareidolia.  When this was released it was used to fuel a conspiracy theory of an aliens on Mars.

In 2001, NASA put any questions to rest regarding this weird formation.  The Mars Global Surveyor took a high resolution picture of the same formation when the sun was at a different angle (below).  I can still kinda make out where the eye and nose is, but it clearly just a rock formation.

Pareidolia is something we all experience.  It is literally hard-wired into our brains.  We can even experience audio pareidolia.  Our brains are amazing things, but we always need to remember that they can be fooled.  Sometimes clouds are just clouds, rocks are just rocks, and shadows are just shadows.  Enjoy the photos, but be skeptical.

For more see the Skeptics Dictionary 

Images courtesy NASA

August 16, 2009

Zombie Ants

A new scientific study has proven the existence of mind-control and zombies!

Ok, not exactly. However, a new study suggests that a fungus does take over the bodies of ants. This weird parasite, Ophiocordyceps unilateralis, infects carpenter ants. The ant doesn't immediately die, though. Instead, the fungus controls it, causing it to travel to the ideal location for the fungus to grow. The ant crawls up understory plants, and clamps onto the underside of a low leaf. The ant then dies here, and the fungus continues to feed on the body, preserving only the exoskeleton and the mouthparts. After a few days, it erupts from the corpse, revealing a stroma. Spores are released from this, floating down to infect other ants.

Though the scientists aren't sure how, the fungus have very precise control over these "zombie" ants. The team found that the infected ants were, almost exclusively, clamped to the undersides of leaves 25 cm from the ground, on the northwest side of the plant. The conditions in that place are optimal for the fungal growth.

The precision with which the fungus takes over the carpenter ants is a bit disturbing. Scientists are still investigating, to try and understand how exactly it turns unsuspecting ants into zombies. It's a very specialized skill, and a fascinating one.

Credit: Science Daily- Parasite Causes Zombie Ants to Die in an Ideal Spot

August 12, 2009

Talking Dolphins

When people talk, we tend to use short words as much as possible. For instance, I've never heard anyone say, "May I have permission to obtain a dessert composed of milk, sugar, and several additional ingredients?" However, "Can I go get an ice cream?" is a very common question at my house. This rule of communication is known as the law of brevity. Both the listener and the speaker want to put in as little effort to get the point across. As it turns out, dolphins also use the law of brevity when they communicate.

Dolphins use about 30 non-verbal behaviors to communicate. In a recent study, ecologists David Lusseau and Ramon Ferrer-i-Cancho broke up these behaviors into simple units. Jumping and turning are considered individual units. Butting heads, on the other hand, is made up of four units: both dolphins jumping, and then both dolphins using their heads. The team analyzed the behavior of the dolphins and determined that they used simple, one unit behaviors more frequently than the complex behaviors with more units.

This is the first time scientists have seen evidence of the law of brevity in non-human communication. However, with this evidence of it's use among dolphins, many suspect that it is common in other species as well. While it doesn't prove that another species is using language, it is one of the first steps to finding evidence of language outside of humans. And the possibilities that opens are staggering.

Credit: Discovery News- Dolphin Speak Relies on Brevity

Skepticism and a Facebook Scam

Everyday we are assaulted with claims of scientific proof or hear hear a story of the baffled scientists. So how can we sort through all of this information and find out what is real and what is a scam? Whenever you read something or see a claim, there are a things you can look for that should trigger some skepticism.

I recently got an account on Facebook. Less than a month ago one of my friends sent me a message that caught my attention.

Facebook is recently becoming very overpopulated,there have been many members
complaining that Facebook is becoming very slow. Records show that the reason is
that there are too many non-active Facebook members and, on the other side, too
many new Facebook members.

We will be sending this message around to see if members are active or not. If
you are active please send to at least 15 other users using Copy+ Paste to show
that you are still active. *Those who do not send this message within 2 weeks
will be deleted without hesitation to create more space.*

Send this message to all your friends and to show me that you're still active and
you will not be deleted.

Founder of Facebook,
Mark Zuckerber

I am always skeptical of anything that asks you to forward it. Most of the time, if it is an e-mail for example, the person who sent it would have no way of knowing if you forwarded it or not. In this case, if really was Facebook they probably could check if had forwarded the message, but there are other problems.

If Facebook really wanted to delete all of the inactive users, think of what the best way for them to do this is. They could send a message directly on Facebook to every user that has them click a link to confirm that they are active. They could send a e-mail to every user asking them to click on a link to confirm that they are still active. Finally, they could just look at the activity records of their users and delete all accounts that haven't been accessed in say 18 months. Having the users send around a message just doesn't make any sense.

If that isn't enough and you want to make sure that it isn't hoax you can always look it up. The first place I went was, which is a great resource for urban legends and Internet myths. I did a simple search for Facebook deleting accounts and there it was.

So why is this important; all I saved was a little bit of time and annoyance for me and my friends, right? In this case that may be true, but it is the process that is important. This scam, like many, relies on people buying into it without hesitation. There are many scams out there which can be very harmful both financially and even physically. Skepticism is not about being cynical, it's about looking at the evidence behind something. A little bit of skepticism can go along way avoiding scams, and maybe even save your life.

August 10, 2009

Skepticism and Daily Health: Organic Food

Another common "health" product is organic food. Organic products are grown without pesticides, synthetic fertilizers, antibiotics, growth hormones, or genetic modification. This is supposedly better for you, as there are no harsh chemicals in the food. Individuals often claim that it tastes better as well. But, there are a few issues with the idea of organic food.
First of all, the term "organic food" is a major misnomer. All living things, and products from living things, are, by definition, "organic". They are made up of carbon chains. The idea that an apple is not organic if pesticides were used while growing it is really not true. It's still organic. It's just doesn't have a little "organic" certification sticker.

More importantly, there is no proven health benefit of eating "organic" food versus any other produce. In fact, a Biritsh agency recently did a study on the differences between "organic" and "non-organic" produce. There is a very slight difference in the levels of a couple of nutrients, but not enough to actually affect health. So, "organic" food doesn't have any health benefit in that regard. Also, to date, there is no good evidence showing that pesticides in food hurt humans. The levels are too low.

So, "organic" food isn't significantly different from any other produce. If you happen to like it better, for taste or whatever, that's your choice. But the science isn't there to support paying more for "organic food" because of its health benefits.

EHSO- Pesticides in Your Food
BBC News- Organic 'has no health benefits'

August 9, 2009

This is just Amazing!

For me there are two things that I just love in astronomy: pretty pictures and violent collisions. When the two come together, you get amazing images like this.

This incredible image is of something careening through Saturn's rings. Whatever this object is, as it's sailing though the rings, it's dragging a trail of debris behind it. The long shadow is being cast because Saturn's rings are almost edge on towards the sun. The exact process that created this dazzling effect still seems to be a mystery. For more on this check out Phil Plait's blog. Whatever it is it's awesome. This is why I love science.

August 8, 2009

What is Science? (Occam's Razor)

Occam's Razor is usually presented as "the simplest answer is usually right". Occam's Razor is a great tool for evaluating different claims, but this everyday statement is a little oversimplified. It was the medieval monk William of Ockham who said "plurality should not be posited without necessity." The best way of putting Occam's Razor might be "the idea that adds the least new assumptions is most likely to be true." There are a few different ways to think of this principle.
One way it is often used to remove unnecessary elements of an idea. A good example of this is the origin of life. We don't fully understand how the organic soup of the primordial Earth formed the first life (although we are getting closer). People have proposed the hypothesis that a alien species planted life on the Earth. To accept this hypothesis, we have to add the assumptions of the alien race, their knowledge of our planet, and we still have the problem of how they originated. Because of this, Occam's Razor would have us chose that it was a chemical process that gave rise to life. Occam's Razor is not evidence or proof for an idea, but it can tell us which is more likely to be correct.
Occam's Razor is also used incorrectly by many pseudoscientists, like ufologists. They say that the simplest answer to all of the blurry photos, crop circles, and anecdotal reports is that there are aliens visiting our planet. The mistake they make is that we can explain these things without making any new assumptions about our universe (for example people have admitted to hoaxing crop circles). The ufologists claim requires us again to add the existence of an alien race that is visiting the earth, a very large assumption.
If one idea is supported by more evidence then another, go with the evidence. If the evidence is equal, Occam's Razor is the tool of choice to decide which idea is more likely.

August 7, 2009

A Cosmic Display

Every August I spend at least one night laying out under the stars and watching one of the most spectacular shows. This is the Perseid meteor shower. If you've never seen a meteor shower, it is a sight to remember. A meteor shower happens when the Earth passes through debris left behind by a comet. This particular meteor shower is made up of debris no larger than about a pebble left behind by comet Swift-Tuttle.

The meteor shower will peak around August 11th, and you should get a good show as long as you are within a few days of that.  I would recommend trying to get away from any large city, although you should still be able to see the brightest meteors in light polluted areas.  This year sounds like it should be a particularly good show, with estimates for the peak as high as 200 meteors per hour.  To watch this spectacle just look up into the sky after it gets dark.  You will probably see the most meteors looking roughly North-East in the early hours of the morning (midnight to 4am).  The only problem this year will be the moon.  The moon will be high in the sky for the best nights.  This is unfortunate, but shouldn't stop you from having a great night.

The streaks of light you will see are dust and ice left behind by the comet burning up in our atmosphere.  It is a common misconception that the reason they burn up is because of the friction with our atmosphere.  What is actually happening is they are compressing the air in front of them and that compression creates heat.  It is unlikely that any of the any of the meteors you see during the Perseid will ever hit the ground.

I plan on heading up into the mountains near where I live a few nights after the peak with a sleeping bag and some friends.  I hope you all have clear skies and enjoy one of the most amazing sights the sky has to offer.

For more information I recommend

August 6, 2009

Martian Meteorite Confirmed!

Block Island, which I talked about earlier today, has been confirmed by Opportunity to be the largest ever meteorite discovered on Mars. It is apparently a iron nickel meteorite. This indicates that it was formed as part of the core of a large asteroid. Opportunity also took images that were used to create this 3D image of the asteroid. Enjoy.

Image courtesy NASA

Scientific Unknowns: Dark Energy

Last week, I talked about dark matter and how it is a placeholder name. Dark energy is essentially the same thing, only for a different problem.

When we look out at distant galaxies, we see something very surprising: they are all running away from us. At first glance, you may think that means that we are at the center of the universe. One thing you realize when you study science long enough is that this is a common first guess, but it has yet to ever be true. The reality is that all galaxies are running away from each other. This is because the universe is expanding.

Think of this like a balloon. Put just a little bit of air in the balloon and then draw dots all over the balloon with a marker. If you then continue to inflate the balloon the dots all move away from each other. From the perspective of any one dot it looks like all of the other dots are running away from it.

When scientists first discovered this expansion they expected that it would be slowing down due to gravity trying to pull everything together. What they found was that the expansion of the universe is speeding up. Dark energy is the place holdername for whatever it is that is speeding up this expansion.

Dark energy is literally one of the greatest mysteries in astronomy today. Some estimates say that it makes up 70% of our universe, yet we have no idea what it is. That is a big hole is our knowledge of the universe and I can't wait to see what fills it.

For more information on dark matter and dark energy you can check out NASA

A Meteorite on Mars?

I have been out of town for the last week so I'm doing a little bit of catch up. While I was gone, the Mars rover Opportunity made an amazing discovery. It found what is probably a meteorite on Mars.

Whenever I have the chance, I love to examine meteorites. The fact that you are holding a rock from space is a really incredible experience. I can't imagine how the scientists at NASA felt when they saw this rock just sitting there. This rock is being called "Block Island." The pitting you can see is very similar to how meteorites here on earth look. Opportunity is planning on using its X-ray spectrometer to see what this rock is made out of and confirm that it is a meteorite.

Images courtesy NASA/JPL

Dynamic Earth: Plate Tectonics

To understand many of the changes that occur on our planet, we have to understand the nature of the Earth's crust. The surface of our planet is not a solid mass; instead, it is divided up into plates. It's sort of like a big jigsaw puzzle, with each plate being a puzzle piece. However, these plates don't sit still. They move around, at a rate of around 5 cm per year (also the rate at which fingernails grow). And, because there isn't a lot of extra room, these plates collide. What happens next depends on what type of plate they are, and how they collide.

There are two different types of plates that make up the Earth's crust: continental crust, and oceanic crust. Oceanic crust is heavier than continental crust, so when the two collide head-on, the oceanic crust dives beneath the continental crust, in a process known as subduction. The oceanic crust melts as it enters the mantle. The magma formed, along with the way the continental crust is pushed upward, creates mountain ranges. This is occuring right now along the west coast of South America.

When oceanic and continental crust collide at angles, a different type of process can also occur. Transverse faults form where two plates are sliding along each other in opposite directions. One of the best examples of this is the San Andreas Fault in southern California. West of the fault, the state is on the Pacific plate, moving north, while east of the fault, it is on the North American plate, moving south. At some point, thousands or millions of years in the future, California will end up in Alaska. Right now, though, this transverse fault is a worry, as it is the reason California is so prone to earthquakes. But, more on that later.

Occasionally, continental crust collides with continental crust. In this case, one of the plates has to give, but niether wants to subduct. It ends up acting similar to a car collision, where the crust crumples as the two plates collide. A collision of this sort is occuring between India and Asia, and is creating the Himalaya mountains.

Finally, oceanic crust almost never collides with other oceanic crust. Instead, oceanic plates move away from each other. This creates a gap, through with magma from the mantle seeps up. The mid-oceanic ridges are actually the boundaries between oceanic plates!

A view of the plates on the modern Earth
There's a lot more to plate tectonics than I can fit into a post. So, for more information on how plate tectonics works, how it has affected the planet in the past, and how the Earth might look in the future, I recommend the Paleomap Project.

August 4, 2009

POP: Preparation

From out in the field, the next step is actually getting the fossils prepared for research or display. There are a lot of different techniques for preparation, depending on what type of fossil is being worked on.

Leaves and Invertebrates
Leaf fossils and invertebrates are often not removed fully from the rock, as they are too fragile. Instead, small air scribes are used to carefully remove rock from around the fossil. This reveals intricate structures in the fossils: veination in leaves, stripes on insects, spines on trilobites.
Sometimes, acids and other chemicals are used to prepare the fossils as well. This technique has to be very delicate, however, so as not to errode the fossils along with the rocks.
Fossil cystoids, before and after preparation
Most vertebrates are prepared out of the rocks entirely, though not all. Fish fossils, particularly, are often left in the matrix, as was the famous Archaeopteryx specimen. Small air scribes, dental picks, water, acetone glues, and a lot of patience are generally the tools of choice. Preparators have to work slowly, so as not to damage the bone. In fact, it takes about 300-500% more time to prepare a fossil than it does to take it out of the field in the first place. Every bit of exposed bone has to be carefully reinforced with superglues, as well, so it doesn't crumble away. It's a tedious process, but a necessary one. Without preparation, not one fossil could be studied or put on display in a museum.
A saber-toothed cat skull, before and after preparation

For more information, visit the DMNS Follow a Fossil site, and read the preparation section.
Image credit: Marc Behrendt Preparation

August 3, 2009

What is Science? (Self Correction)

Science is not a stagnant thing.  It is constantly changing and correcting itself.  Science is better seen a process of getting information than as a body of information.  One of the hallmarks of science is this self correction.  In science, no idea is above being challenged or immune from criticism.

Pseudoscientists often present scientists as trying to maintain the status quo.  In reality, the opposite is often true.  If a physicist could collect evidence that gravity was not the curving of space but something else, they would become one of the most famous physicists of our time.  The reason that this is done so rarely is that in science, you have to have the evidence.  Well-accepted theories have lots of evidence behind them, and in order to overturn them you would need more evidence than supports the original claim.

One field where ideas are constantly being overturned is medicine.  New drugs are studied rigorously to demonstrate effectiveness and safety.  After years of study, the drug can be approved by the FDA.  Once the drug is approved, people continue to test it.  If at any point the drug is show to be unsafe the FDA will pull it from the market.  Good doctors will prescribe treatments that have been shown to work with minimal side effects.  If new risks are discovered they stop prescribing the treatment.  These are both really good things.

Another good example is the Piltdown Man hoax.  This was a forged fossil of a early human ancestor.  The fossil reflected what paleoanthropologists at the time thought our evolutionary ancestors would look like.  Because of this, the scientific community of the time did not suspect a hoax.  Over time more real fossils were found and Piltdown Man became an anomaly.  As it became more of an exception it started to be ignored until finally it was revealed as a hoax.  For more on Piltdown Man, see Talk

It was Carl Sagan who said "In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day."  It is sometimes hard to admit that you are wrong, but if we don't we never move forward.  Science is always striving to move forward, and therefore always correcting itself.

August 2, 2009

Comet Calamity?

It is commonly accepted that asteroids are capable of causing mass extinctions. The extinction of the dinosaurs, 65.5 million years ago, for instance, is widely considered to have been caused by an asteroid impact. However, the idea of similar mass extinctions being caused by comets is not very likely, according to the finding of a new study.
First, Jupiter and Saturn seem to do some shielding. They have much more gravitational force than the Earth does, and so can provide some protection from incoming comets. The scar found on Jupiter is evidence of this.
Also, according to the new study from the University of Washington, the probability of actually getting hit by a comet is very low. Most long-period comets, the sort that might cause an extinction event, are part of the Oort cloud (the remnants of the cloud from which our solar system formed). The study used a computer model to estimate the number of comets in the Oort cloud. From this prediction, they determined that only 2 or 3 comets could have hit the Earth during the most intense comet shower over the past 500 million years. These impact would have been nearly simultaneous, matching an extinction event occuring 40 million years ago. However, that extinction was relatively minor. Thus, it is highly unlikely that comet impacts caused any mass extinction events. The chances of comets getting past Jupiter and Saturn is small, and those that do aren't likely to hit our planet.

Credit: Science Daily- Crashing Comets Not Likely the Cause of Earth's Mass Extinctions

August 1, 2009

Speciation in Action

The process of evolution is the way in which organisms change into something else. speciation, the process that splits two populations of the same species into two separate species, is central to evolution. Scientists can observe genetic changes in the lab, and can see the results of speciation in many different animals and plants. Darwin's Galapagos finches are still a wonderful example of this. However, there aren't many opportunities to catch the process of speciation in action. A little species of flycatchers has provided one of these rare opportunities.

J. Albert Uy, of Syracuse University, has conducted a study of the Monarch flycatchers, common on the Solomon islands. There are two varieties of this little bird, separated by a change in only one gene. Because of these, the flycatchers on one island are all black; the flycatchers on another have chestnut-colored bellies. The males of the species are very territorial; if another male enters an individual's territory, the intruder is attacked. Yet, interestingly, chestnut flycatchers rarely attack black flycatchers, and visa versa. This suggests that the chestnut and solid black varieties no longer recognize each other as potential competitors. This, in turn, means there is little to no interbreeding between the varieties. As a species is defined as a set of creatures that can mate and produce viable offspring, the two varieties of Monarch flycatcher are on a path to become separate species.

This is an amazing new piece of evidence to evolution. The fossil record is good, but too incomplete to provide absolutely definitive evidence. Microevolution (evolution on a very small scale, that doesn't necessarily create new species) can be readily observed in the lab, but macroevolution, like what is occuring now with the Monarch flycatchers, is not easy to see in action. Hopefully, these populations continue to be observed over time, so that the process of speciation and evolution can be documented.

Credit: Science Daily- Study Catches Two Bird Populations as They Split into Separate Species

What is Science? (The Burden of Proof)

Pseudoscientists often say, "You can't prove I'm wrong; therefore, I'm right."  The mistake that they are making is where they place the burden of proof.  In the American court system (I know that it is different in other countries), you are considered "innocent until proven guilty."  This means that it is the job of the prosecutor to prove the defendant guilty.  Another way to say this is that the burden of proof is on the prosecutor.  In science, the burden of proof works in a similar way.

If I purpose a new hypothesis, say that flying unicorns exist, it is my job to prove it.  The burden of proof is always on the person proposing the new idea.  This is done for two reasons.  If it was the job of scientists to disprove every claim that came their way, they would never have time to do anything else.  The other problem is that vague claims like the one above are logically impossible to disprove.  All you can say is that they are extremely unlikely to exist.  On the other hand proving that flying unicorns exist would be quite easy, all I have to do is find one that can be studied.  If you hear a wacky idea, ask for evidence.  Don't let them wiggle out of that by asking you, or anyone else, to prove them wrong.