Category Archives: geography

What Lies Beneath

 

Curious Friends, Today we will talk about a very strange world within our world. I dont know if Science Fiction writers know about this but if they did they could write hundreds of stories about it.

 

      About 15 million years ago the poles of the earth started freezing. Antartica was formed. Before the freezing there was a lake in Antartica. When freezing took place ice formed over the lake. So this lake was covered with a sheet of ice about 3.5 kilometres thick. Now the lake itself did not freeze. It was just cut off from the atmosphere by a 3.5 kilometres think ice sheet.

 

 

      This lake exists today. And it has water which was cut off from the rest of the earth 15 million years ago!!!!! It was discovered in 1977 near the Russian Antartic station Vostok. So this was named Lake Vostok. It is very large : 14000 sq Kms and is deep ( about 500 metres).

 

      There is no way to reach this lake. It is deep(3.5 Kms) below ice. So the only way is to drill that deep. Once the Russians decided to drill and get water samples from there. But about 400 feet from the lake they stopped. They realized that any drill would contaminate the lake which has remained “untouched” for 15 million years.

 

 

      This lake would tell us a lot about the kind of conditions that existed on earth 15 million years. Maybe fish from 15 million years ago is still preserved there. Also who knows, this lake may still have life that has completely gone off in a different direction than the rest of the life on earth. You would ask? But how is life possible without sunlight. It is possible. Life exists in Marina Trench( See VERITAS: The Limits of Ocean Depth 4 Jun 2003. I am appending it for your convenience) which is 11 kilometres deep and has NO sunlight. Life in such places exists near hydrothermal vents( where the hot gases from earth’s core come out). So life can exist in places without sunlight by using the heat from the earth’s core. Who knows, maybe there are hydrothermal vents in Lake Vostok.

      Also we have seen( VERITAS:Europa 17 Jul 2003 [availabe to new people on request] ) that Jupiter’s moon Europa has something similar. It has thick ice covering oceans of water. Maybe life in these Oceans on Europa has  a resemblance to the life in lake Vostok.

      The biggest problems before Scientists is to get some samples of water from lake Vostok without contaminating it. They are experimenting with different devices to do this. Till that happens, we can only imagine what lies beneath that icy wall.

 

 

 

               Death was in that poisonous wave,

                    And in its gulf a fitting grave

                    For him who thence could solace bring

                    To his lone imagining-

                    Whose solitary soul could make

                    An Eden of that dim lake.

                              ( Poe – The lake)

 

 

 

Kanwar

 

 

 

 

 

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  Go, wondrous creature! mount where Science guides:                 

  Go, measure earth, weigh air, and state the tides:                 

  Instruct the planets in what orbs to run,                          

  Correct old time and regulate the Sun;                             

|======================================================|

 

 

The Magnetic Reversal

 

   Curious Friends, in today’s VERITAS we will explore the  earth’s magnetic field and some strange phenomenon related to it. This article is inspited by something that my friend Amit Chopra told me.

        The exact cause of the earth’s magnetic field is still a mystery to man. The magnetic field of earth resembles the field of a giant bar magnet buried in the centre of the earth. But this could not be the reason because the core of the earth is very hot ( more than 1000 degrees

celsius) and at this temperature  any permanent magnetism is lost. The most likely cause of earth’s magnetism is that molten charged lava is constantly flowing in the core. These electric currents cause earth’s magnetism. This theory is called the dynamo theory of earth’s magnetism.

        The field of earth’s magnetism is huge. It extends several thousands of kilometres into space. The magnetic poles of the earth are slightly tilted with respect to the axis of earth’s rotation. But these poles are not static. They keep changing their locations independently of each other and are not always at opposite sides of the earth.

Nobody has a good theory to explain why the poles keep changing their locations.

        Every once in thousands of years something very dramatic happens!

The earth’s magnetic field reverses its direction! The north pole becomes south pole and vice versa!!! The average time between reversals is about 250000 years. But this time is not always exact. It varies from thousands to millions of years. The actual reversal takes about 1000 years. This also is not always the same. It may take as little as 100 years for the poles to reverse . And there is evidence that atleast once in earth ‘s history the polarity of the magnetic field remained the same for 30 million years. The most recent confirmed flip occurred about 780,000 years ago.

        How do scientists know that earth was once magnetized in the opposite direction? Rocks that solidified at a particular date always contain a record of the magnetic field at that date. Rocks collected below deep oceans and lakes show a definite magnetic field effect opposite to what we have today. When these rocks solidified by sedimentation thousands of years ago their crystal structure oriented itself to the magnetism of that time.

      Scientists believe that the earth’s magnetic field weakens over time after each reversal and after a long time it shuts off. it then appears again. It may appear again with the same polarity( this is called geomegnetic excursion) or it may appear with the opposite polarity ( reversal). Measurments carried by scientists over the last 150 years have shown a constant decrease in the magnetic field strength. The magnetic field has decreased by about 10 % since 1845. So in about 1000 years or so the magnetic field will shut off for some time to reappear again with either the same or the opposite polarity.

        No body knows why the earth’s magnegtic field changes direction. Several scientists are working on this but nobody knows for sure.

        If the magnetic field reverses how will it affect us. As I mentioned earlier the magnetic field of earth extends several thousands of kilometres into space. It protects us from the harmful effects of charged particles emitted by the sun. These charged particles interact with the magnetic field and are deflected around the earth. There are belts around the earth where the magnetic field has trapped a lot of charged particles. These are called Van Allen Belts. At the north and south poles the interaction of these cherged particles with the magnetic field produces brilliant radiation: the northern lights( aurora boleris) and the southern lights ( aurora australis).

   Curious Friends, sometimes Science too becomes a victim of fashion. We see today that every young Physicist wants to just do research in particle physics or field theory. But there is mystery everywhere. Our Earth’s magnetic field is as mysterious as anything else. One should not follow the fashions. One should follow nature and nature alone:

 

                ….. First follow nature and your judgement frame

                By her just standard, which is still the same

                Unerring NATURE , still divinely bright

                One clear, unchanged and universal light

                Life, force and beauty must to all impart

                AT once the source, and end, and test of Art

                Art from that fund each just supply provides

                Work without show and without pomp presides:…..

 

                                                        -Alexander Pope

 

kanwar

 

|======================================================|

  Go, wondrous creature! mount where Science guides:                 

  Go, measure earth, weigh air, and state the tides:                 

  Instruct the planets in what orbs to run,                           

  Correct old time and regulate the Sun;                             

|======================================================|

 

The Limits of Ocean Depth

 

      In today’s VERITAS we shall explore the deepest point of all oceans. We will see if life can survive the extreme conditions of these depths.

      The deepest point on earth is the Challenger deep located in the Marina Trench. This is located north of New Guinea in the Pacific Ocean. The depth of this point of the ocean is about 11 kilometres(6.8 miles). So if you could place Mount Everest there, it would be submerged with 1 km of water over its peak.

      We know very little about places so deep below the sea.

Light lasts to about 200 metres below the sea. By 500 metres it is pitch dark. The top 200 metres where there is still light is called the “photic zone”. Photosynthesis can only occur in this shallow zone. Below 100 metres the temperate drops to 2-3 degrees C.

Pressure increases rapidly. For every 10 metres the pressure increases by 1 atmosphere. SO extreme conditions start even before we reach the 500 metre depth. You can imagine( or can you?) the conditions at the bottom of Challenger deep. Would life survive there? Imagine the weight of 11 kilometres of water on you!

      Yes, there is life at the bottom of the Challenger deep.

There are certain organisms which absolutely need high pressure to maintain their body processes. These are called barophilic organisms. Their cell membranes have different protein composition. Their enzymes are bound differently. Normal enzyme bindings get weak with pressure.

      So the Challenger deep has life in the form of microbes which love pressure. It also contains more complex creatures. Shrimps, scale worms and sea cucumbers are also found there.

So we see that several different kinds of creatures live there.

What do they eat? They eat smaller organisms! But it has to start somewhere! Most the life that we are familiar with starts from the sun with plants producing food from sunlight. The rest of the creatures eat plants or other plant eating creatures.

At the depth of Challenger deep what is the primary source of energy?

Sunlight cannot reach there. What is at the bottom of the foodchain?

At the bottom of the foodchain are creatures that take energy from the hot core of the earth. The Mariana Trench has chimneys and hydrothermal vents which release smoke from the hot core of the earth. These hydrothermal vents release poison gas, heavy metals, acids, and heat. Some Creatures survive by oxidizing the hydrogen sulfide that is released by these vents. This process is called Chemosynthesis. 

The rest of the creatures eat these creatures. These hydrothermal vents are home to colonies of creatures that use the stuff released from them.

      These releases from the vents may seem like food for the organisms that live in the deep. Far from it. For most of these creatures these gases and heavy metals are extremely toxic. Also these vents create extreme heat that these creatures are not used to. Liquified heavy metals can clog the mouths of these creatures killing them instantly. Only for a small set of creatures these chemicals act as food. The rest just depend of these creatures and these stay away from the vents.

      Fish has been found till a depth of 8.5 kilometres( 5.2 miles) in the Challenger deep. These fishes have no eyes( no light so no eyes).

      How deep has man gone? The deepest that a man could descend was to a depth of just 90 metre from the Challenger deep floor.

Submersibles with robotic arms have touched the ocean floor several times.

      Some beautiful lines from Lord Byron’s poem: The Sea:

 

       Roll on, thou deep and dark blue Ocean,–roll!

       Ten thousand fleets sweep over thee in vain;

       Man marks the earth with ruin,–his control

       Stops with the shore;–upon the watery plain

       The wrecks are all thy deed, nor doth remain

       A shadow of man’s ravage, save his own,

       When, for a moment, like a drop of rain,

       He sinks into thy depths with bubbling groan,

      Without a grave, unknelled, uncoffined, and unknown.

 

Kanwar     

 

|======================================================|

  Go, wondrous creature! mount where Science guides:                 

  Go, measure earth, weigh air, and state the tides:                 

  Instruct the planets in what orbs to run,                          

  Correct old time and regulate the Sun;                              

|======================================================|

 

The Longitude Problem

 

      Until a few days back I had no idea of who John Harrison was and what his contribution to Science was. THis VERITAS is thus inspired by a wonderful program telecast on National Geographic that made me aware of this remarkable genius and the importance of his work.

      An urgent petition reached Parliament on March 25 , 1714 . 

Certain “Captains of Her Majesty’s Ships, Merchants of London , and Commanders of Merchant-men” wanted something done about the day’s most pressing problem in navigation, the problem of longitude.

      In those days Sailors never could accurately know the longitude of their position. They could never know(precisely) how close or how far they were from a particular landmark. This resulted in numerous accidents. For example on October 22, 1707, at the Scilly Isles near the southwestern tip of England, four homebound British warships ran aground and nearly two thousand men lost their lives.

      There were several ways to solve this problem. The two major ones were : the astronomy solution and the clock solution. The astronomy solution relied on the sailors observing the skies(planets, moons stars) to find out their exact longitude. But this solution was not practical for sailors:

A huge telescope is okay on land but imagine a sailor trying to look at jupiter on the deck of a ship tossing voilently at sea. It was not practical at sea and it did not work for sailors.

      The other way to know the longitude was to know the time at your current position, know the time at a standard position( London for example) and to relate the longitude to the time difference. It was known that for every 2 minutes time difference you are half a degree away from the reference point. One could always know the local time at a place:

The sun’s elevation will tell you that accurately. However how would a sailor know the current time at the reference point. Let me tell the readers that this is not such an easy thing. As the Great Newton himself pointed out: “…by reason of the Motion of a Ship, the Variation of Heat and Cold, Wet and Dry, and the Difference of Gravity in Different Latitudes, such a Watch hath never been made.” Remember that in those times clocks were pendulum clocks. Imagine what effect a tossing ship would have on a poor pendulum. :-(.

      Several scientists tried their brains at this problem and failed.

THis list includes Newton , Galileo , Halley , Cassini . This problem was ultimately solved by John Harrison a watchmaker with a love for Science.

      In 1714 the English parliament announced a prize of 20,000 pounds to anyone who could solve the longitude problem within half a degree of latitude or 2 minutes of time. The instrument would be taken on a ship to West Indies and tested there with respect to longitude(time) of London.

        Harrison was twenty-one years old when Parliament announced the prize.  He was born in 1693 at Foulby in Yorkshire, the eldest son of a poor carpenter. Harrison in his spare time studied Physics and Mechanics.

      Harrison worked alone. None of the Great scientists of the time paid any attention to his work. In 1735 Harrison made his first clock called H1. It had not one but two pendulums which were joined to one another. The effect of Gravity on one was compensated by the other. However there was still the problem of pendulums increasing in size due to temperature difference at various places. In 1740 Harrison built H2. But its design was wrong and it failed too. From 1740 to 1759(19 years) Harrison worked on his next clock, the H3. It had two new inventions of Harrison: a strip made of several strips of 2 metals to compensate for expansion due to changing temperatures and a caged roller bearing which reduced friction drastically. Despite that The H3 failed to meet the standards and was discarded.

      Harrison realized that his clocks were too big. In 1755 he started work on a tiny pocket sized watch with all his inventions inside it. H4 was tried in 1761. A ship carried it to Jamica on a 60 day journey . And the watch was accurate to a remarkable 5 seconds. It was a feat! But no one was convinced! Imagine what the top scientists would have felt when they got to know that a simple watchmaker had done what they had considered impossible. So Harrison was not awarded the prize.

He was asked to disclose the secret of his watch. Some scientists thought that the watch was a freak and no other like it could be made. The watch was kept by the Longitude Board and asked a watch maker to replicate it. Harrison was disappointed. He started work on H5. In 1770 Harrison went to the King of England himself. The king himself put H5 to trial and was impressed. The Longitude Board was however reluctant to give Harrison the prize. They only gave him 8000 Pounds. But more importantly he was recognised as having solved the Longitude problem.

      Harrison had worked on the problem for 45 years. He was 80 years old and had crossed swords with the leading lights of his day before solving the problem. In a sense he was a TRUE scientist. He tried untiringly and patiently on what he believed was right. And he did not care what others thought would or would not work . 

 

In the year of Harrison’s death, James Cook sailed again to the Pacific , where he demonstrated beyond any doubt the utility of the chronometer in marine mapping.  Nearly two centuries later , the honored guest at a dinner at 10 Downing Street was an American, who rose to propose a toast to John Harrison.  His invention , the American said, enabled men to explore the Earth with precision and , when most of the Earth had been explored, to dare to build navigation systems for voyages to the Moon .  “You, ladies and gentlemen, started us on our trip .”  The speaker was Neil. A. Armstrong.

What is inside the earth

 

      As all of us have studied the earth’s interior in our school days .

Now lets look at it it again . Earlier the earth was molten . Then the lighter elements like silica , oxygen started coming to the top and the heavier elements like nickel and iron started going towards the centre .

The layers at the top cooled off . But the interior still remains hot.

The earth now has 3 layers :

 

1) The crust : this is where we live . It extends upto 30 Km deep .

   It is cool and brittle . It tends to break during earth quakes .

 

2) The Mantle : This extends from 30 kilometres to 2900 kms below the

   earth . It accounts for most of the earth’s volume . It is composed of

   Iron , Magnesium , silicon . All earthquakes , volcanoes orignate from

   this layer . It is semisolid . It has a temperature of about 1000 degrees.

 

3) The core : The core has two parts :

 

   a) The outer core : This is liquid . consists of molten iron and nickel.

      It has a temperature of about 3700 degrees . 

   b) The inner core : Because of intense pressure this is a solid ball of

      iron . It has a temperature of > 4300 degrees and is about 5200 Kms

      deep .

 

How do we know what is inside the earth ??

 

Well there are various ways to find out . When waves generated by siesmic activity ( such as earthquakes ) goes from one layer to another it bends ( like light bends on hitting a surface with different refractive index ) .

 

another way is to study the insides of the earth is to study the two types of siesmic waves : The compressional P waves and the shear S waves .

The compressional P waves can travel both in solids and liquids . The shear S waves can travel only in solids ( in liquids if something is pushed sideways there is very little resistance ) .

 

      So suppose an earthquake occurs in New York and you observe the waves on the other end of the earth . Scientists observed that till a seperation angle of 105 degrees you get both P waves and the S waves thru the earth . After a seperation angle of 105 degrees the S waves ( Shear waves) disappeared completely . That means that the waves are passing thru liquid . By some trignometrical calculations u can find the radius of the liquid inside the earth .

 

      The earth’s Magnetic field can also be explained by the movement of the liquid in the core . The moon and Mars have no magnetism .

To account for the magnetic field in the earth the convection has to be very rapid . The liquid iron seems to be charged and its rapid movement causes the magnetism .

 

      We can also learn a lot about our magnetic field by observing the field of Sun which is similar but stronger . The magnetic lines of force twist arouund the core and then they rise to the top( cooler layers) .

Here they become cyclonically twisted till a release happens in form of sun spots . The sun’s Magnetic field reverses its polarity every 22 years .

If you apply the same equations to the earth then we see that it should change its polarity ( south becomes north and vive versa ) every 250,000 years .

 

      Scientists when studying old rocks have observed that the orientation in which the rocks are laid/frozen does show us that about 300,000 years ago the earth’s magnetic field was indeed opposite to what it is now .

 

Panama Canal

Here is the story of the construction of Panama Canal . It turned out  to be a much bigger challenge than people first imagined .

 The complete article ” the unkindest cut ” is in www.discovery.com .

 I am just gonna talk about some parts that I thought were important/interesting

 

 

 The idea that a canal should be built thru Panama to connect the Atlantic

 and Pacific ocean and save ships from a 12,000 mile journey around South

 America was as old as 1513 .

 

 The first attempt to make this canal was by the Frenchman : Ferdinanad

 de Lesseps . He had built the suez canal earlier . I 1883 work started

 on the panama canal . 20,000 workers started digging . But progress

 was too slow . The terrain was mountaneous and had thick forests.

 ( suez canal was build thru a desert ) . Then because the french

 cut too many trees , this resulted in landslides . And then disaster

 struck . By 1884 yellow fever( caused by a mosquito ) was killing

 200 workers a month . The project was scraped in 1889 . A failure !

 

 

 In 1903 the AMericans started building the canal after suppressing

 a local revolution and creating a new state “Panama ” . In 1905

 Yellow Fever struck again killing workers . But the Americans had

 a plan . They asked a tropical disease expert Dr Walter Reed to

 suggest something . The plan was executed by Colonel William Gorgas .

 He installed wire nets(worth 90000 $ ) , fumigated houses , improved

 sanitation and by December 1905 the disease was finished !!!!!!!

 

 The person incharge of the canal Stevens was a very methodical

 chap . He spent 2 yrs planning the infrastructure etc . He

 suggested a canal with locks( I dont know what this means )

 But Stevens was replaced by Col Goethals. Goethals executed

 Steven’s ideas and the canal was completed in 1914 . Yippie !!

 

 The total cost : 639 million $ .

 

 If u make a mountain out of the earth moved it would occupy 1 city

 block and would be 19 miles high . coool aint it !!  

Incas

The Incas were a fierce warrior tribe that ruled Equador to central Chile between 1200 and 1535 AD .

 

The architecture of the Incan cities amazes scientists . They built their cities on the steep sided of the Andes Mountains . The cities had stone steps leading upto them and the building blocks were massive blocks of stone . These stones were so tightly fitted together that not even a blade could pass between them .

 

The Incas had a very strong hierarchial structure in their society .

The Sapa( priest ) , the ruler were at the top . Then were the councilors. After that came temple priests , regional commanders . The lowest level were farmers , workers etc . Even women could rise to the top and could occupy any position .

 

They developed a system of irrigation and this led to surplus food .

The Inca population prospered and grew . The Incas had a great army .

They build strong fortresses on the tops of mountains . The most famous Incan fortress is at Sacasahuman located at the Incan capital Cuzko .

 

The Incas also had a complex religious system . They worshiped the animal spirits and had complex religious rites. In Incan paintings the heaven are depicted by the Condor , the underworld by the Puma .

The incas also hhad a elaborate calendar.  The sun temple( remember Tintin ) in Peru had the calendar inside it .

 

The Incas were very cruel people . The punishments were very severe .

They didnt have any prisons . Why ? because all punishments were by crusl deaths . Culprits were thrown off mountains , or had eyes , hands removed etc . They didnt need prisons .

 

The 40,000 memner Inca army was destroyed by the Spanish Army . In 1535 the inca sociaty was wiped out . One of the reason of the destruction of the Inca society( according to Discovery Channel ) was that when the Incas came in contact with the Spanish they also came in contact with bacteria/virus which the Europeans brought with them . The Europeans were immune to these virus . But the Incas had no defences . Epidemics caused the Inca society to perish . This also shows the destructive power a new bacteria/virus can have on a different/new population .

Timbuktu

You may have heard the name Timbuktu in many songs or a mention of it in comics or funny stories .

 

      There is actually a place called Timbuktu and it has a very interesting history.

 

      Timbuktu is a city in the West African country Mali . It was a post on the trans-saharan trade route . It lies on the southern edge of the Sahara desert just 8 miles from the Niger river .

 

      It was founded in 1100 AD as a seasonal camp by  the Tureg Nomads .

It was incorporated in the Mali Empire in the 13th century by the Mali Sultan Mansa . He built his royal residence and a great mosque there .

 

 

      In the 14th century Timbuktu became a centre of trade and learning .

Salt from the north was exchanged with gold from the south here . Many

Muslim scholars settled here to spread the teachings of islam .

 

      In 1591 it was captured by Morocco . Most of the city’s scholars

were either killed or arrested . Timbuktu continued to be disturbed by

attacks from various tribes until 1893 when it was captured by the French .

 

      It bacame a part of various tales of adventures of Europeans trying

to explore the Sahara . It bacame famous in stories and songs as a desert

city .. inaccessible and full of mystery .

 

      In 1960 it became a part of the republic of Morocco .

 

      It is now easily accessible by camel or road and is an important

administrative town of Morocco .