We’ve been working hard on making this trip very affordable for students and members of the U of A Scuba Club and we’re happy to announce that the price this year will be $650 which includes all hotel costs, diving costs (not including rentals) and breakfasts for 7 nights at Blue Angel Resort. To break it down a little further, the details are as follows:

- 7 nights at Blue Angel Resort in a shared room (choice of roommate available, added cost for a single room)
- 7 buffet style breakfasts at Blue Angel’s amazing restaurant (note: this isn’t a cheap continental breakfast; bacon, eggs, pancakes, fruit, coffee, etc… are all served!)
- 10 boat dives on Cozumel’s protected reef, along with unlimited shore diving

The dates for the trip correspond with U of A’s spring break, which falls between February 20th and 27th for the 2010/2011 academic year. The days are are also nicely aligned with a Westjet Edmonton to Cozumel direct flight, which avoids many of the travelling pitfalls we experienced last year due to travelling through the US. In any case, you are free to choose your own flights, but if you’re interested in staying up to date with deals, I will be looking for specials on the Westjet flights mentioned previously. At the moment, these regularly priced flights are about $450 each way, or $900 total. I expect to get these flights half-price when the come on sale towards the end of the summer. In terms of renting gear, our sponser Ocean Sports is providing us with a fabulous rental deal over the course of the week. For last years trip, all told the rental was around $100.

Additional meals at Blue Angel’s restaurant are extremely affordable. If prices remain similar to last year, you can eat happily and healthily over those 7 days for about $200 per person (about $15 per meal). I highly recommend this option, because it takes a load off in terms of planning, shopping for and storing groceries when on Cozumel Island.

A conservative estimate puts the trip cost around $1850 plus certification fees, although this can be as low as $1500 if a good deal on flights comes around. If you know you’d like to join us on the trip, please contact me using this address (cozumel@uofascuba.com) so I can arrange payment of your deposit to Ocean Sports through Megan Plemel (megan@oceansports.ca). Please feel free to address me directly with any questions. I hope you decide to come, it’s a ton of fun!

Here are a couple of images from last year that might entice you a little… This first one is a group shot on our last day in the dive shop where we’d store our gear and get set up for our daily dives.

Here’s a shot of the restaurant with the dive shop below. The view from the hotel is incredible: facing west you can see the sun set every day, along with the ocean and multiple cruise ships that amble by to stock the island’s resorts with eager tourists.

A group shot on the boat, taken candidly. We’re on our way back from two dives.

Enjoying some local entertainment while out for dinner in downtown Cozumel.

Preparing for a night dive off the beach at the resort.

Heading into the darkness!

First of all, let me say that the dive resort we stayed at was beautiful! There wasn’t a beach, per se, to lounge on, but there was plenty of space to lie out in the sun. Our fantastic photographer, who graced me with his pictures, (I broke my camera two days into the trip) took all the pictures that I’ve posted here. On the right is a photo from the hotel overlooking the restaurant (above) and dive shop (below). The light blue water was the shore dive domain, and in the distance you can see the fence of the ray pen of the neighbouring property. The package we booked with Ocean Sports and Blue Angel included unlimited shore diving, even at night. There was a tonne of life at every dive site we visited, due mostly to the fact that the area was designated the Cozumel Reefs National Park by presidential decree in 1996. Also included in our package were two boat dives a day for five days with additional boat dives at $50 for two. Over the course of six days, my dive number more than doubled, with 18 logged dives by the end of the week. As a group, we had four divers earn their PADI Advanced Open Water certification, with Peak Performance Bouyancy, Underwater Naturalist, Underwater Navigation, Deep and Night dives. We also had one of our group complete his Night specialty. Our instructor for the week, Kari Atkins, who is in the photo above as well as the videos below, was pure, 100%, FDA approved AWESOME! I’m getting ahead of myself a little bit, so before I bore you to death with all the little details, get comfortable, maybe have a bathroom break, and when you’re ready, hit up the two videos below along with the commentary below. Both were produced by the Talented Randy Travis of RandyTravisUnderwater.com.

This first video is the Santa Rosa Wall, which was a little under an hour away from the resort by boat. As you can see, we descended to about twenty meters on the sandy shelf and then swam towards the wall, where the bottom slopes off into the deep. We were immediately graced by a nurse shark, which moved steadily against the current so that all of us had a nice view before we were swept away. The current was very strong, pushing us along the gallery of the reef. It was nice for me though, since I was suffering from blisters on my feet from all the activity earlier that week, and if you watch carefully you can see me with my fins crossed, still keeping up with the rest of the group. The dives on the wall were my favourites because of the large number of swim-throughs, small pseudo-caves made out of reef material, that were very interesting to explore and practice our buoyancy skills. Out of all the dives, this one was the most desolate of life, with a very low number of fish, eels and rays. You can compare this to the second video.

This second video was taken on Paradise Reef. This is where we did the Underwater Naturalist part of our Advance Open Water specialty. As opposed to the wall dive, this one was at a depth of about fifteen meters with a relatively sandy bottom. There was an abundance of life here, which was lucky since our requirements for the certification were to identify four types of vertebrate animals, four types of invertebrate animals, and two types of plants. You can see me and the other divers examining our waterproof identification booklets along the way, writing what we see on our dive slates. I bought my booklets so I could show everyone what we saw, since my camera was broken. It’s funny what diving does to you; I remember being surrounded by dozens of species of fish and not being able to find any of them in the booklet, and at about fifteen minutes into the dive I hadn’t written anything down. I was getting so frustrated and I finally recognised that I was stressed and came to a full-stop, took a few deep breaths and said, “I’m going to flip to a page in my book, and wait until one of the fish on that page swims in front of me.” Sure enough, about ten seconds later I ID’d the first fish, and I completed the exercise over the course of the next ten minutes.

All in all, the week passed very quickly. Scuba diving tires you about pretty fast, and two dives a day is more than enough for most people to be asleep before their head hits the pillow, especially when you’re wrestling with current on the majority of the dives. On top of the dives, we would walk into Cozumel city and get dinner and drinks.  Luckily, while we were there, there was a three-day parade many kilometers that went back and forth along the main drag in the evening. We all went out one of the evenings and enjoyed the festivities (and $1.50 one liter beers)! The restaurant at the dive resort was phenomenal, and even more impressive than how delicious and filling the meals were, was the final price, which hardly put a dent in my overall trip budget!

There is much more to say, but I’ll stop here for now. If you’re interested in more details of my trip, feel free to contact me or leave a comment below. I can’t emphasize enough how much fun I had on this trip. I volunteered to organise the trip again next year with the help of the Scuba Club and Ocean Sports, so I count myself very lucky to be able to have another awesome experience next year!

Before we get into the nitty gritty of the assignment, if you’re adventurous, have a look at the source we were given as a reference: A reversible wet/dry adhesive inspired by mussels and geckos[1]. Additionally, I’ll be pulling some extra information from Biological Adhesion for Locomotion on Rough Surfaces[2], which may require a subscription. Now, against my better judgement, I’m just going to copy and paste the questions and answers for the first three problems on my assignment (the others are about the polarity dependence of STM images, see Atom-selective imaging of the GaAs(110) surface). Here goes!

• A gecko walks up walls using physical adsorption forces.  Would the gecko’s ability to walk be altered if the wall was wet?  What about if the wall had a layer of very fine dust on it?

The gecko’s ability to walk up walls stems from special structures on their feet called setae which interact with surfaces via Van der Waals forces (physical adsorption forces). Each seta is roughly 1mm long and 5µm in diameter, terminating in hundreds of fine structures called spatula which are 200nm long and 10nm in diameter. Since these structures are flexible, they can conform to a surface effectively and increase the overall surface area available for interaction.

A gecko’s ability to walk on the wall when wet depends on the force available to each seta. In [1], their artificial “gecko” structure composed of nanopillar array of PDMS 600nm long and 400nm in diameter. These structures had an adhesive force per pillar of 39.8±0.2nN in air, reducing to 5.9±0.2nN in the presence of water. This overall reduction in force per setae by a factor of 7 means that a typical gecko weighing 25g, will have its shear force parallel to the surface of 10N in air reduced to 1.5N in wetness (assuming reduction in force per setae is approximately the same as the artificial structure). Since the gecko weights 25g or 0.025kg, the force due to gravity on a vertical surface is only 0.025kg*9.8N/kg=0.245N, and the gecko will continue to stick. Its ability to walk on a wet surface will be weakened, but not eliminated.

However, actual gecko setae do not suffer the same decrease in force due to thin layers of water because of their ability to squeeze water out between setae [2]. In fact, in [2], they cite another source that claims the pull-off force for a gecko’s foot is reduced by a factor of six when submerged in water. In either case, the gecko’s ability to walk on wet surfaces is diminished, but not eliminated.

In [2], the question of whether a gecko can walk on a contaminated surface is questioned. The answer, it turns out, is that gecko’s can walk on dirty/dusty surfaces for a special reason. It was proposed that small particles would passivate the gecko’s feet, but it was found that geckos never need to clean their feet; this suggests that these small solid particles bind more strongly to the wall than the gecko’s feet. The author of [2] finds this explanation unsatisfactory since adhesive tapes lose their adhesive properties after repeated applications to dusty surfaces. He proposes that the lateral movements of the gecko’s feet scratch these particles off the setae, maintaining their adhesive properties. Therefore, we must assume that the ability of gecko’s to walk on dusty surfaces is diminished, but not eliminated.

• Evolution has created tiny and fairly large (gecko) animals that can walk up walls.  Is it just a matter of time before bigger animals develop similar capabilities?  Or is there some limit that prevents that?

We must consider the ratio of surface area available for adhesion to the weight of an animal. Assuming an animal walks on a vertical surface, the adhesion force must be greater than the force due to gravity (neglecting whether an animal could remain rigid enough to walk vertically, poor giraffe…). For a gecko, each foot is about 100mm², for a total of 400mm², and setae have a density of about 10,000setae/mm². Each seta can withstand 10^-5N shear force, which corresponds to about 0.1N/mm². Thus, a gecko has an available shear force of 0.1N/mm²*400mm²=40N. (Note, however, that the value quoted in the literature is only 10N. We will stick with the ideal case). The weight of a gecko, calculated about is 0.245N, and therefore the ratio of shear force to weight is 40N/0.245N=163, which we require to be above 1. We need our animal to obey this relation (Surface Area of Feet[mm²]*0.1N/mm²) / (Weight [kg] * 9.8N/kg) > 1, or rearranging Surface Area of Feet[mm²] / Weight [kg] > 98mm²/kg.

So a gecko has 400mm²/0.025kg=16,000mm²/kg. An elephant has feet approximately 50cm in diameter (no references), with the largest recorded weight being 12,000kg. So an elephant would have (50cm*10mm/1cm)²/12,000kg=200,000mm²/12,000kg=17mm²/kg (yes, I realise that elephant’s feet aren’t square, I’m just too lazy to divide 50cm by two, convert to mm, square it, and multiply by pi, since the answer will only make up for the fact that I used the heaviest elephant on record). Since 17mm²/kg is less than the 98mm²/kg we require, we are forced (sadly) to admit that a geckelephant cannot walk up walls.

The limiting factor is the surface area of adhesive contact to weight ratio of an animal, which we require to be 98mm²/kg. Since our geckelephant doesn’t meet this criteria (even within a factor of 5), we are forced to admit that there are some current animals which would magically benefit from the addition of gecko-like structures to their feet/hands. Since this is not how evolution works (also, quite sadly) we can assume that the only way a species would develop the ability to walk up walls is if (i) there is an evolutionary pressure to do so, and (ii) the species’ body is within the current limits of a gecko-like foot structure or (iii) the species could evolve to be within the constraints of the gecko-like foot structure or (iv) the species could develop a better adhesive and so beat the constraints of the gecko-like foot structure.

The rest of the questions are based on reading [1], but the most interesting question is the applicability of this science, to which I wrote:

Indeed, there will be practical products based on this science. Cited in [1], for starters are: wet temporary adhesives for medical industrial, consumer and military settings. If the products are reliable, they would be better than current adhesives because (i) they are reusable over may cycles (ii) they work in wet/dry conditions and (iii) they are likely to work in conditions where other adhesives have limited functionality (i.e. hot/cold, low/high pressures…etc.). Just like the buttons/zippers/velcro, these products would find their way easily into daily life.

As with any approach, expanding the limits of functionality by testing in other conditions would be an improvement. They geometry of these structures also needs to be explored, i.e. varying the length/width of the structures, spacing between pillars, adhesive layer thickness…etc. Additionally, a biomimetic structure with a setae/spatula refinement may further improve the structure. In all, this research could be expanded substantially.

Wow, I’m seriously impressed if you read all of that. Have a gecko five!

[1] Haeshin Lee, Bruce P. Lee, Phillip B. Messersmith, “A reversible wet/dry adhesive inspired by mussels and geckos”, Nature, Vol 448, p338-341, (2007).

[2] B.N.J. Persson “Biological Adhesion for Locomotion on Rough Surfaces: Basic Principles and A Theorist’s View”, MRS Bulletin, Vol 32, p486-490, (2007).

Hit the read more link to see a few of my personal tips and guidelines to barter earnestly.

I want to tell you why you need to barter in countries like Mexico. While products and goods have a certain value, vendors expecting to barter tend to have a higher initial price to try to sell their goods for a larger profit. By having a large initial price, vendors are doing something very tricky: calling upon an Anchoring Bias. An anchoring bias is the tendency that most humans have to base their initial valuation of a product on the first price they see.  As an example, if the asking price for an object is $20, so offers tend to be clustered below, but close to the $20 price mark. The same item initially priced at $30 will make offers cluster closer to $30. Vendors know this, and set high initial prices so that your initial evaluation of the product is high as well. Before you look at an item’s price make an earnest estimate of a product’s value before you see the price.

The eHow article says to offer 1/2 of the listed price for your first offer, but don’t be ashamed to offer less if you feel the product is less valuable or your estimate of the value is low. I found 1/3 of the listed price to be a good starting point and offering one third the difference between your last offer and the vendor’s counter offer, with the intention of converging around the 1/2 price mark. (Math geeks: N[Sum[3^(-n), {n, 1, Infinity}]] converges to 1/2.)

Always be prepared to pay what you offer. If you and the seller agree on a price, the worst thing you can do is renege on the deal. To avoid this, only carry what you are willing to pay into a sale. You can do this by going to the shop and examining the product, then privately moving only the amount of money you are willing to pay into your wallet or purse. This is also a devious but effective method of driving down the price, since you can show the vendor how much money you “have”, thereby nullifying any attempts to make larger counter offers. As a less devious alternative, I wrote a budget for my final day in Playa del Carmen and used the amount of money I budgeted for gifts as a bartering tool.

Finally, and in addition to step 4 in the eHow article above, always be prepared to walk away from a purchase. Don’t just turn and walk away from the seller. If the price is still too high for your preference, thank the seller for his time earnestly, then move along. The seller will usually make a last-ditch attempt to sell the item at your last offer price. If this is the case, thank them, make the purchase and move along.

That’s all I’ve got for now. I will be spending a few weeks on the island of Cozumel in the near future, and I intend to explore the intricacies of bartering for services (specifically massages and haircuts). I’ll update you on my successes (or failures)!

First of all, I tend to read a lot of books, but I don’t necessarily think this is a prerequisite for owning an eBook. If you compare the price of best selling eBooks with the price of physical copies, you can justify the cost of an eBook reader with as little as 25 books, a conservative reader’s yearly quota. After that, any further purchases are savings that stay in your pocket.

However, I think the eBook Reader excels at a different market than new releases and best sellers: the classic book market. With website like Project Gutenberg and Feedbooks, getting a classic novel that’s properly formatted for your device is as easy as downloading a file and transferring it to your device. Of course, there will be naysayers that say the best part of reading a book is flipping through it, smelling it’s old pages, and keeping it on the shelf. Let’s be serious here, if you want one of these classics, and your serious about collecting them, then you aren’t going to settle for less than a first edition. If you aren’t going to settle for less than a first edition, then you aren’t going to spend less than the cost of an eBook Reader on the book. If you want to read the book, then an eBook reader fits the bill. You won’t worry about dog-earing pages, cracking spines, or getting hot sauce on it. (You want to be careful with an eBook, in the way your careful with any electronic device, but a little hot sauce wipes off no problem).

Next come the naysayers that don’t think eBooks look as good as paper. They’re getting there, and while I can’t say much about the PRS-600, whose screen is nigh unreadable in low light or specular lighting due to the high reflectivity of it’s touch screen layer, the PRS-300 is a good competitor to a standard paperback. In fact, I’m going to go out on a limb and say that the PRS-300′s screen is better than a standard paperback for 2 reasons: one, it renders fonts flawlessly, unlike some prints that smudge or otherwise mar the ink on the page; two, it has a brilliant white background in natural light that rivals the contrast of a typical paperback, more so than aged and yellowed pages of older paperbacks. On top of those two reasons, the viewing angle is only limited by how oblique of an angle you are willing to read by. Here’s a quick shot of the screen (exert from Walden by Henry David Thoreau):

The benefits of the PRS-300 over regular books are it’s size, portability and manageability. It’s about the same width and height of a typical paperback, and about a third as thin. The PRS-600 and Kindle are both a bit larger in width and height, but still on the order of a typical hardcover. So yes, it’s smaller than a book, so it can go anywhere a book can go. It’s also denser, the PRS-300 can hold about 350 standard books. That’s not to say that you’ll be reading them all simultaneously, but if you fill the reader up at the get go, you’ve got 350 books to read before you have to do anything but charge it (don’t worry about charging it though, the battery lasts about 2 weeks of use, or about 4000 pages, in my experience). What do I mean by manageability? I mean that you don’t have to hold an eBook open to keep your page, you don’t have to use two hands to change pages…etc. I found this to be incredibly useful while eating, since I can use my hands for regular food activities, and touch the reader only to change the page. It’s also much easier to remain in a comfortable position while lying down, since you don’t have to alternate between the left and right pages of a book.

Before you go out and buy your own eBook Reader though, there are some points to consider. Although the software is getting more user friendly, Sony’s eBook Library and Adobe’s Digital Editions software are a major pain in the ass. I’ve personally switched to the open-source Calibre to manage my library and synchronize my books with my PRS-300. Although it’s simple to use, if you aren’t a tinkerer and you don’t like frustrating moments with finicky software, I would nudge you towards the Kindle, since it has wireless connectivity and a built in bookstore (it also can access Wikipedia for free).

I’ve currently read over 1000 pages on the PRS-300 and there’s no slowing me down. I’ll be burning through books on this thing until one of us kicks the bucket. As always, if there are any questions, I will be happy to answer them in the comments below.

One of my all-time favourite tools for predicting interesting events in the sky is Heavens-Above.com. With the website you can check the configuration of the planets and stars for almost any night (a reasonable time past and present), check the rise and set times of the Sun and Moon, and predict what satellites will be visible, and where and when they’ll appear in the sky. I’ve even found it useful for identifying an object after I’ve seen it. I’ll give you a quick run down of how to use it and what cool things you can see (no telescope or binoculars required)!

The setup is pretty simple, but if you get this even a little bit wrong you can end up missing something incredible, like an Iridium Flare.

First of all, Heavens-Above requires that you manually enter your location and timezone to give accurate results, so step one is:

1. Configure your location:

Go ahead and pop over to Heavens-Above.com, and you’ll see something like this screenshot:

Once you’ve got clicked the ‘select from map’ link, you’ll be taken to a page like the following:

Add a marker by clicking on the map, then choose your timezone, and click submit. I’ve added the University of Alberta’s Observatory for my location. Now we’re ready to rock and roll!

2. Checking the night sky

Once you’ve completed the configuration, you can hit the ‘Whole sky chart’ link on the main page, under the astronomy heading. I won’t give you a direct link, since it will depend on what your location is. Once you’ve got a chart, you can manually adjust it by manipulating the Year, Month, Day, Hour and Minute fields. I usually check two charts before I head out: one from the beginning of the observing period and one at the end. That way I will know roughly what I can expect to see over the course of the time I’m outside. Note that the Hour box takes the 24 hour convention as input, so if you plan on going outside at 9:00pm you’ll want to enter ’21′ into the box.

3. Finding interesting satellites

There are numerous options from the main page, and although Heavens-Above does a great job with the whole sky chart, the Sun, Moon and planetary data, where it really shines is under the ‘Satellites’ heading. There you’ll find my favourite link: ‘ISS’ and ‘Iridum Flares’. Each of these links will spit out a table like the one below. Here I’m looking up International Space Station passes over my location for the next 10 days:

As you can see, there are only three passes, but luckily there’s one tonight starting at 8:10pm! The rest of the data in the table let’s you know where the satellite will be in the sky. The ‘Alt’ (altitude) parameter represents how high off the horizon the satellite will be in it’s starting, maximum altitude and ending position. This number is given in degrees, with 0 degrees representing the horizon and 90 degrees representing the zenith, or the point directly above your location. The ‘Az’ (azimuth) parameter represents the angle in degrees from North, counting clockwise. So 0° is north, 90° is E, 180° is S, and 270° is W.

With something like the International Space Station you will see a faint spec in the sky as it comes into view, with a relatively constant brightness over the course of its trajectory. If you are observing the ISS in the evening, it will appear near the western horizon and travel across the sky. Then it will disappear into the shadow of Earth (cool!).

Iridium flares are very different from the ISS. They tend to be quite dim, so it helps to have a dark sky to be able to see them, however, at one point in their trajectory you’ll get an incredibly bright flash as their main antennae reflect sunlight. These satellites can have many trajectories, since there are a few dozen in various orbits around Earth.

If you are having trouble with anything else on the site, it hosts its own Frequently Asked Questions section at the bottom of the page where your question is sure to be answered! Good luck, and happy satellite hunting!

The ATM cave was so cool that I’m going to hit you with a read more link to get the rest of the goodness, see you after the jump!

Let’s get straight down to buisness. The ATM cave is formed by a system of streams that flow through the ground in the Tapir Mountain Nature Reserve. To get there our tour group took an early morning van ride from San Igancio into a region that was covered by orange groves. We had a short stop at the last sign of civilization, only to find the most foul-mouthed parrot I had ever heard.

From there is was only a short drive to the edge of the jungle and the path that would eventually lead us to the entrance of the ATM cave. If you are planning on doing this trip, it takes up almost a full day. There’s about an hour hike to the entrance of the cave through the jungle, which is full of very interesting plant and animal life. For the most part we only saw insects, but our guide knew a ton of stuff about the plants. Along the way, it’s necessary to cross a stream several times. I say stream, but I was given to believe that it was at it’s lowest point of the year. Our knees got wet, but it wasn’t much of a challenge to cross.

Before we entered the cave, our tour group served us a horrible lunch of tuna and cucumber sandwiches, so bring your own snacks. We also had a chance to have a dip in the pools which formed at the mouth of the cave. The water was refreshingly chilly, since it was incredibly hot and humid. I also noticed schools of tiny fish, which looked very close to the aquarium style Tetras you can buy here in Canada.

After lunch we got suited up with our helmets and our headlamps and it was off to the races. The entrance of the cave was a deep pool, that we had to swim across. Oh, and advice to weak swimmers, bring along a strong swimmer. In most cases the parts of the cave that you have to swim across are short and shallow, but occasionally there is a very deep pool, so it helps to have someone who can help you along. There was a 60-ish year old woman who was with us that wasn’t a swimmer at all, and the tour guide gave her assistance along the way (needless to say, she didn’t make it all the way to the end of the cave, so she turned back when we met up with an earlier tour group on their way out).

Only a few dozen meters into the cave the darkness started overpowering our tiny headlamps. The following picture is looking across a large chamber towards the entrance of the cave. I tried getting a shot of the giant stalactite which the Mayans believed was the physical representation of the guardian of the underworld. It was a suitable symbol, but as you can see below, very hard to take a picture of (without a flash, of course).

The trek into the cave lasted for over two hours, and we had more luck with wildlife in the cave than we did in the jungle. Inside the cave we saw a blind cave crab and a few cave fleas, which I think are more closely related to crickets than they are to fleas. There was also evidence of bats everywhere, although I didn’t see a single bat along the way. In the picture below you can see an awesome limestone formation in the foreground. In the background of the image you can see the ceiling of the cave, along with some strange holes. The holes are actually formed by the bats. Apparently when they are hanging from the roof and they poop, some of their poop hits the roof above them and slowly dissolves those holes into the roof. I have no idea how it works.

So after about two hours hiking, swimming, scrambling we come to a point where there is a giant ledge, about 5 meters high and a single boulder that reaches up to it. This it the most challenging part of the hike, since it’s a wet, slippery, and wholly eroded rock that stands between the cave and an incredible cathedral underground. This is where the 60-ish year old woman got turned around. She spent about 15 minutes trying to climb this rock, but kept getting freaked out by the height. It was entirely psychological, since about a dozen people were giving her help. I felt incredibly bad, because as soon as we had climbed onto the ledge, out tour guide started pointing out signs of human life, notably sacrificial pottery.

The number of artifacts in this part of the cave were staggering. The chamber that we were in could literally house the largest cathedrals that I had ever seen. Everywhere we stepped we had to plan carefully so that we didn’t disturb relics of the past. We were even require to take our sandals off and walk solely in our socks, to prevent our sweat from damaging the artifacts and the interior of the cave. The cave was used about 1000 years ago as a place of religious sacrifice to the god of the underworld. There were even remains of humans that had been sacrificed, many of them bludgeoned on the head with special tools that had been found near their resting places. The picture below is a skull illuminated by a red LED. One of our tour members had strayed off the path and almost walked on it, but our tour group was watching everyone carefully, so there was no risk of damaging it.

One of the most famous features of the cave is know as The Crystal Maiden. It’s a complete skeleton of a teenage female that was sacrificed in the cave. The skeleton had been covered with layers of calcium carbonate as the water levels in the cave rose and fell through the rainy and dry seasons over the course of a millennium. Our tour guide speculated that she had been hit in the face, because her jaw was inhumanly askew, and then left for dead in the cave. Her resting place is high up above the main chamber, which means it is possible that she was trying to find a way out of the cave when she finally succumbed to her injuries. There is a skeleton nearby of a very small person, who would have been her guide in the underworld, since she was likely to be a Maya royal. This point marked the end of the tour where we would have to turn around and head back to the jungle.

The return journey was an excellent way to reconcile how difficult it must have been for the Mayans to access this cave, let along discover and explore it in the first place! Several of our group member’s headlamps had started to go dim (mine included) and luckily our group leader had packed some extra batteries for us. Can you imagine how difficult it must have been to accomplish a journey like that with only fire based light sources? You have to remember that we swam almost a third of the time we were traveling through the cave, sometimes through crags and cracks that were so small that our largest companions had difficulty getting through them!

By the time we had finished our hike out of the cave, we were exhausted. We were inside for nearly 4 hours, and in addition to that we had to hike another hour just to get back to the van. Before we packed up for the hike I had a celebratory swim in the entrance to the cave, to celebrate my return from the world of the dead. I’m looking forward to visiting again!

You can click any of the pictures to enlarge, and read a brief description of each one. If I had to say only one thing about my trip it would be this: I had an amazing time and there is more for me to learn in this part of the world. I will be going back time after time. There is one thing that I would have changed about the trip: either I would have done the whole thing without the benefit of the GAP tour company, or I would have brought along someone who could have joined me for the tour. Without the benefit of a partner in crime, it was a bit awkward being alone in a tour group.

On to the gallery! Enjoy!

35 Toyota Venza’s ($32,000) + 100 Cash Prizes ($10,000) + 1,000 Toshiba Laptops ($700) + 25,000 Tim Cards ($100) + Winning Rim Tabs = $38,019,185

Total number of cups: 281,686,000

Overall expectation value: $38,019,185 / 281,686,000 = $0.134970091

There is more data available in the Contest Rules, but strictly speaking I’m not interested in what my expectation value is for winning the Toyota, nor do I want to complicate things by recalculating my odds based on what province I’m in. So you can expect to win 13-ish cents on each cup you buy.

Happy rolling!

Well, at least there aren’t rules against drinking in public (or internet cafes for that matter), *sip* ahhh.

Every restaurant has the motto “slow down”. Everyone here will tell you if you’re walking too fast. I was told to relax by a chef on the street, and I was already pretty friggen relaxed. I’m burnt as hell, the SPF 45 is almost meaningless. Tomorrow I’m SCUBA diving in the Spanish Bay and having a night dive at the local reef. Today I snorkled with nurse sharks, eagle rays, sea turtles, and saw those neat fish in symbiotic relationships with other fish. There are thunderstorms over the horizon which illuminate the clouds shrouding the moon.

I don’t think I’ve ever been so happy in my life.

So I’m not going to use the internet for the rest of the trip. We’re leaving for Playa del Carmen the day after tomorrow, and I’ll be home Saturday night. I’ll do a big round up post, and a couple of packing advice posts about what I used and what I didn’t. But other than that, I hope you’ve enjoyed the last couple of posts and I encourage you to post your questions or e-mail them to me so that I can answer them in the big round up.

The beer is beckoning. Over and out.