Had A Long Day?

Have you ever felt that your day has been very long? Has it ever happened that you wanted to just rush back home and crash on your bed but it never seemed that the night was coming anytime soon? Well, it may not be completely because of your tired mind playing tricks. You can put part of the blame on the Earth and part of it on our nearest neighbor in space, the Moon. Thanks to the interactions that these two have been having since their birth, the Earth's rotation is slowing down and our days have been growing increasingly long, albeit at a pace which is unnoticeable in a single lifetime. To get a hang of how slow this process is, let's have a look at some numbers. An average day in the Devonian Period, approximately 420 million years ago, was around 21.8 hours long. That's around 8000 seconds shorter than our present length of 24 hours. After all the mathematics, the Earth is losing approximately 20 seconds every million years. If that is not slow, I don't know what is.

An artist's rendition of the protoplanetary disk and the early Solar System

Let's first answer this primary question. Why does the Earth rotate in the first place? We all take it for granted but we never really do ask why it happens. Well, simply put, the Earth's rotation is a remnant of the angular momentum of the original dust and debris that formed the Solar System. This dust and debris coalesced to form planets which gained this momentum and started rotating as a result. Other factors contributing to the rotation also include the hypothetical impact that formed the Moon and mantle-crust interactions as well as tidal action.

So why this downward trend in the speed of rotation? As I mentioned above, we do not have to look far for an answer. Our own Moon and its gravitational pull are culpable. We all have studied back in our school days that the attraction of the Moon and the Sun are the reason behind the tides that rock our shores four (two low and high tides respectively) or two (one low and high each) times a day. So far so good. We assume that the water of the oceans are pulled directly towards the Moon. This is where we go wrong. 

The tidal offset as a result of the Earth's rotation

The Earth's rotation drags this tidal bulge a little ahead of the position directly under the Moon. Now, this tidal bulge contains a sizable amount of mass of itself and this mass does not lie on the line that joins the gravitational centers of the Earth and the Moon. As a result, there exists a torque (in simpler terms, a rotational force) between the two bodies. This torque acts in the direction opposite to the Earth's rotation and decelerates it while at the same time, further increases the speed of the Moon in its orbit.

The Moon is not the lone culprit. The Earth's crust and its molten interiors contribute to this slowdown as well. Any interaction between the solid crust & mantle and the liquid core results in a drag which makes the Earth go that tiny bit slower. Major tectonic activities have also played their part, although not always to decrease the speed. For example, the Indian Ocean Tsunami on 26th December 2004 which was a result of the Sumatran Earthquake, cut 6.8 microseconds off from our day and no one (except some scientists) was the wiser.

You must be wondering how, apart from making your day even longer than it seems to be, does this affect your daily life? How does an increase in the day's length by two-thousandth of a second change anything? You would be surprised by how much.

Ever used a GPS to track your way through the maze that you call a city? Now, the GPS signals that help you pinpoint your location travel at the speed of light - 30,00,00,000 metres per second. This is roughly equal to 0.4 metres in one nanosecond. Imagine if you let the time go uncorrected and let the GPS satellite and the receiver on the ground go out of sync by that two-thousandth of a second each day, it will be a miracle if the GPS even shows you standing in your own city. Even as you are reading this blog, perfectly timed transmissions of data from all over the world come together and form this page without a glitch. A microsecond slip in this transmission and all you would be seeing right now would be a colourful mess.

Another peculiar phenomenon, predicted to occur billions of years into the future, is tidal locking. A tidally locked body rotates around itself and revolves around its neighbour at the same speed causing one side of the former to constantly face the central body. The best example of such a body is the Moon whose far side never is seen from the Earth. But, if this deceleration in Earth's rotation goes on, even the Earth will become locked and then only one side of the Earth will face the Moon. The Moon will be over a single place permanently in such a scenario.

Only one side of the Moon faces us due to the equal length of its rotation and revolution time.

To correct this and prevent this mess from happening (no one can prevent the tidal locking; I meant the GPS errors), there is a leap second, much like the leap year, which is occasionally added to keep the length of the day in check and not let it drift away from the atomic time (which is widely used in all the systems now). You can read more about it here :
http://en.wikipedia.org/wiki/Leap_second

Well, not to make your day any longer than it already has been, I'll finish this here and let you ponder over what you have read. Wishing you all the best of luck. Longer days lie ahead....

They Ruled The Earth Before Us

The Age of Reptiles ended because it had gone on long enough and it was all a mistake in the first place.

- Will Cuppy, How To Become Extinct (1941)

I haven't read the book nor did I hear about it until a week ago when I was surfing away on the World Wide Web and chanced upon this quote from the book (I have to admit - the title is quite eye-catching and I might be found reading it in the near future). I also do not know the context in which this sentence is used within the book but I do disagree with Mr. Cuppy's view here. For those less proficient in the Geologic Time Scale, the Age of Reptiles was the Mesozoic era which started around 251 million years ago and ended nearly 65 million years ago. It is so called because of the ridiculous dominance that the reptiles enjoyed over Earth, especially the most popular among their family, the dinosaurs for the whole duration of this era. These 'terrible lizards' (the literal meaning of dinosaur in Greek) were the undisputed rulers of this planet for nearly 186 million years. In comparison, we, Homo sapiens, have been around for just about 2,50,000 years out of which nearly half that time was spent solely in the continent of Africa. I don't think we have earned the right. So, what unique characteristics did the dinosaurs possess that helped them lord over the lands for that amount of time? How were they different from their contemporaries?

The Age of Reptiles, a 34 m mural depicting the period when reptiles were the dominant creatures on the earth, painted by Rudolph Franz Zallinger.(for full image: http://donglutsdinosaurs.com/wp-content/uploads/2012/02/Age-of-Reptiles-1000x302.jpg

Numerous theories have been put forth to explain this long reign of the dinosaurs. Ranging from post-apocalyptic survivors to sheer luck, these theories cover almost all the ways that they could have adopted to pull through some hard times. I wish I had the time to discuss all of them.

The first dinosaurs appear in the fossil record some time after the largest mass extinction in the Earth’s history at the end of the Permian period. Known as the ‘Great Dying’, the Permian extinction event decimated most of the existing reptile and amphibian groups. A large part of the ecosystems and various kinds of ecological niches were up for grabs after being vacated in such dramatic fashion. According to studies, the dinosaurs formed a part of the group that led the recovery of these ecosystems in the Triassic period that followed. However, in the early years of their evolution, dinosaurs were one of subordinate groups and largely remained under the radar as other reptile groups diversified. This would remain unchanged throughout the Triassic and, as luck would have it, another major mass extinction event occurred, this time at the boundary of the Triassic and Jurassic period. This event is attributed to have accelerated the rise of the dinosaurs (who survived) to the top by getting rid of the competition.

It was not just mass extinction events that helped the dinosaurs on their way. Evolution played its role too. A variety of unique features are shared by all dinosaurs that set them apart from any other vertebrates and more importantly, the other reptile groups. Anatomically, there were two changes that are of particular importance, providing an important evolutionary advantage to early predatory dinosaurs. Unlike their contemporaries and predecessors, the dinosaurs had an upright stance. This was aided by strong knee and ankle joints which were firmly attached to the shin bones with a hinge joint at both ends. This vastly improved their speed and agility and gave them that extra edge over other slower organisms.

Dinosaurs were odd physiologically as well. You see, most reptiles today are ectotherms i.e. they are cold blooded and need external sources to maintain their body temperature. However, our illustrious giant lizards were allegedly endotherms (warm blooded) and there’s proof. Their growth rate was phenomenal when compared to their reptilian brethren and it is comparable to living warm blooded animals. Their bone textures (irregular as in mammals as compared to the neat parallel rows of typical reptiles) and oxygen isotope ratios of extremities (¹⁶O and ¹⁸O ratios depend on temperature) also point to the same conclusion – dinosaurs maintained their own body temperature.

I really want to talk more on this topic but the other reasons are way above my level and I wouldn't be able to do justice to those theories (also, I can't risk losing my readers, can I?). I would be glad if someone has something to contribute to this though. So, I will bring this post to an end with a cheesy and dramatic paragraph.

It is truly remarkable that this group of animals, nearly non-existent at the start of the Triassic, could go on to leave such an everlasting impact on the planet’s history so much so that young human beings would be fascinated when a movie featuring them would be made nearly 65 million years after their demise. We may never learn the reason behind this dominance but one thing is for sure – it was not a mistake.

As Colourful As It Gets

When I was a kid, the only thing I was good at (and my mum will probably stand testimony to that) was smearing colour all over me and anything around me. As children, everyone of us was fascinated by that chart on the last page of our drawing books which showed us what we could obtain if we mixed the basic colours. (if you don't remember, have a look here : http://www.siliconimaging.com/ARTICLES/CMOS%20PRIMER/image006.gif )

All in all, most of us retain this childish allure for anything that exhibits a multitude of colour. There are very few examples in nature that are as captivating when it comes to this. One among them are minerals. And, as if to prove me right, I was noticing my classmates when our professor was teaching us the reasons behind these wonderfully coloured crystals. All their eyes lit up when a gemstone was shown on the screen and when the professor actually handed out some from his collection, everyone forgot that there was a lecture going on. (believe me the stone hadn't even gone back into the paper packet and most of the class was already half-asleep.)

Now, you find a variety of colours in minerals. Thousands of hues and shades of all possible colours are seen. Over time, a geologist sees so many minerals that nothing amazes him. And there is nothing more omnipresent than the mineral that makes up the sandy beaches that mark our shores - quartz.

Quartz is such a mineral that does not evoke any curiosity. White and transparent - there is hardly anything that is interesting. But, sometimes even this oft forgotten member of the mineral world conjures up something that makes us sit up and notice it. Purple amethysts and yellow citrines (pictured below) serve to remind us not to write anyone off so easily.

Yes, agreed, crystals are pretty but there is a cryptocrystalline variety of quartz that is sometimes as beautiful as the ones above. And, if you need proof, have a look below. Believe it or not, these are just some of the extraordinary range of colours that can be exhibited.

(Photo credit : David Englund; http://www.davidenglundphotography.com/)

(Photo credit : David Englund; http://www.davidenglundphotography.com/)

Known as agate, these beautiful mineral specimens are classically associated with volcanic rocks. They are generally found in nodules or hollow cavities in volcanic rocks formed by volatiles previously present in the lava and it is their monochromatic or coloured bandings that are their most striking features. Now, the burning question is - how do these bands form or more precisely, how are agates formed?

It all begins with a cavity in the rock, preferably in a volcanic rock. Water containing SiO2 (silica - the composition of quartz) percolates through these holes and the mineral starts to crystallize. In the initial stages, the concentration is high and the silica in the solution is in a polymerized state. This is supposed to lead to rapid crystallization in the form of fibrous crystals which nucleate on the wall and grow inwards. This makes the first layer very fine grained. It is followed by a comparatively coarser layer of quartz. However, the solution is an open system with continuous variation in the solute and the solvent due to external sources of water and silica. Thus, when the concentration gets high enough again, the silica crystallizes rapidly and voila! You have your peculiar bandings, all the result of  these periodic changes in the concentration of the silica in the fluid.

And, the vivid colours that make agates so valuable and appealing to the eye are the result of trace impurities in the form of transition metals. Iron, manganese, copper are some of the ions that impart these colours to them. Iron oxides make the bands go red, brown, black or green depending on the various factors like oxidation state etc. Oxides of manganese colour the layers pink, violet or black. There are various combinations of these ions that bring about the other shades that are seen.

Sometimes, however, the concentrations don't vary as time passes and the silica keeps getting depleted as the crystalliztion proceeds inwards. This results in progressively coarser quartz grains towards the centre and we have what we call a geode (they are some impressive freaks of nature - fully formed crystals enclosed in a rock. Do check them out!)

Notice how the layers become coarser towards the centre.
(Photo credit : David Englund; http://www.davidenglundphotography.com/)

But this is not the place to be talking about geodes. For now, focus on the hypnotic beauty of the agates. I'll be back soon with some other stuff...

The List : Krem Liat Prah

What was your first reaction when you read the title? Is this guy talking about a Chinese movie on his list? Or maybe, it was : he has lost it after just five posts. Sadly, I am still sane and this is another awesome addition to The List.

Krem Liat Prah is the largest natural cave in India. It is situated in the Shnongrim Ridge of the Jaintia Hills district in the state of Meghalaya, northeast India. Currently being surveyed in the Abode of the Clouds Expedition, its length is approximately 25 kms and more is being added to that as connecting tunnels are discovered. It is carved out of limestone and contains some spectacular caverns, one of which is called the Aircraft Hangar. (Well, they must have named it that for a reason, no guesses why!)

Krem Liat Prah   (picture courtesy: Hugh Penney; flickr.com)

And that's not it. Liat Prah is not the only cave in the area. There are around 150 other caves, not as large as Liat Prah but equally spectacular.

So, now that you are all in awe and amazed at the beauty and extent of the cave, let's get a little geological insight into it as well. How are these formed? And why here of all places? The reason is simple - I mentioned it before - limestone.

Limestone is a sedimentary rock composed primarily of calcium carbonate. CaCO3 is one mineral which dissolves so easily that I sometimes wonder how it even forms huge massive rock deposits! So, as groundwater makes its way through these rocks, it carves out a path and over a period of time enlarges them enough to create these marvels. And, sure enough, the Jaintia Hills, where these caves are found, are composed of  limestones belonging to the Prang formation of the Sylhet Group. Massive, fossiliferous and grey, these limestones are from the Eocene Period (approximately 48 MYA to 34 MYA) and form a thick succession which is perfect for the formation of an underground network.


Going by the extra ordinary proportions of Krem Liat Prah, it is a surprise it has remained hidden for so long. Not anymore. Its wait in the shadows ends now. Time for some spelunking!

So Where Are The Comments?

First of all, I would like to apologize for the lack of posts. I've been quite busy with - midterms, competitions and above all, journal completion. But don't you worry. I've got a lot of stuff lined up for the next few weeks. I'll put it up soon enough for you to enjoy - that's assuming you enjoy reading my posts.

So, that brings me to my next point. At the start of this blog, my first post had emphasized on the fact that I am doing this to try and create a network of young geologists like us. But I do not see that happening. I mean, if you really do enjoy reading my posts (again, just assuming) I guess Blogger would have told me to get out because the comments section was getting flooded with, well, comments.

I do not ask you to start a conversation everytime I post on the blog. But what I ask of you is that if you really think that this is a good initiative, help me make this better. Help me reach out to the thousands of geologists who never get a chance to speak out. It is only with your feedback that I can improve or else I'll just keep posting whatever I like. And that really doesn't serve any purpose at all.

If you are confused on how you can contribute, here are some pointers - 

YOU COULD

• comment on the post and share it (well, sorry, that was a little obvious).
• send me written articles about something interesting that you found and that you would like to share with us. My email id is right beside the photo of the handsome guy you see to your left.
• suggest a topic on which you would like a post either by mentioning it in a comment or via email.
• if you know me personally, I would like you to let your friends know that I am an awesome guy and that I do not put emails regarding any query into my spam folder.

These are just some of the ways you could help out (feel free to innovate and find out new ways to spread the word).

So, that's all for now. Keep your eyes peeled for the expected posts.

Peace Out.

The List : Balancing Rock of Jabalpur

Let's start off with a weird entry...

Balancing rocks are known worldwide for their gravity defying appearance (and also partly because everyone likes to take a picture with them trying to push it off). Now as the name suggests, they mostly occur as large boulders (some as big as buses) resting on other rocks. The most astonishing part about these features though is that they are naturally occurring. The term however is not technically sound; not all 'balancing' rocks are 'balancing' themselves but are actually firmly attached to the rock below. But who cares right? As long as they don't topple over on you while you are busy capturing what would probably end up as your Facebook profile picture.

Now, some of these are so famous that just a picture of the feature can lead you to naming the place where it has been clicked.

The one in Utah, US, is by far the most popular among these. The total height of ‘Balanced Rock’, as it’s called, is about 39 m, with the balancing rock rising 16.75 m above the base (The big rock on top is the size of three school buses).

Balanced Rock, Utah (photo credits : Jean-Christophe Benoist)

Then, there’s the one situated at Kjeragbolten, Norway. Suspended at a height of 984 metres, it takes a lot of courage to go stand atop that. Have a look and decide for yourself.

Kjeragbolten, Norway

However, what is not known is that we have our own stuntmen in India. In Jabalpur, Madhya Pradesh. Formed as a result of erosion of volcanic rocks, these are said to have survived an earthquake of magnitude 6.5 on the Richter Scale. Given below are some pictures that show how precarious it is. Agreed, it is not as spectacular as some of its more distinguished siblings but hey, it's a wonder of nature too!

                                     

Balancing Rocks at Jabalpur (source : http://www.jabalpurtourismpc.com)

Don't you agree that this is worth a visit? There are many such hidden gems that are waiting to be discovered. But that’s it for The List now. Got to study. As they say, got to maintain the right ‘balance’ in life.

The List

How many of you have heard of the Grand Canyon? If I had asked you to raise your hand if you had heard of it, 99% of the hands would have gone up (The 1% is for those who were probably scratching something or gorging on some snack while reading this). Now, if I mentioned the Yellowstone National Park (last seen in the geologically horrible movie, 2012) or the Meteor Crater in Arizona, less hands would shoot up but it is still quite popular.

But what if I asked you where we find fossilized dinosaur eggs in India? Stumped right? It is mildly amusing and very surprising that we do not have much knowledge of geological sites that exist right in our own backyard. Not that I do not understand the importance and significance of the above mentioned sites. It's just that maybe it's our own fault when we dream of going to these world-famous sites and crib about it when we can't (money issues!) when all we have to do is hop on a bus or a train and tour our own country which has no shortage of similar wonders.

So, for the next few days, I am going to be mentioning some of the sites that I happened to come upon in my quest to find a cheap and fun way to satisfy my geological curiosity. Do tell me about any sites that you would want to have known or that you would have heard of and would like to visit.

Let's begin The List....