Day: November 23, 2020

Tobacco and Slavery

When America was in the process of colonization by European powers who began settling their people there, they required large numbers of labors to work on their farms. Most of the people who were enslaved and sold in America were Africans.

The transatlantic slave trade involved many millions of people, and its history and legacy have had an impact all over the world. There were European slave traders, ships’captains and sailors as well as African traders and the African people captured and enslaved.

They cultivated the land which were highly fertile and produced crops in vast quantities. Colonizers saw that these crops were commercial in nature. The produce were shipped to Europe and earned huge profits. One of these was Tobacco.

Dunhill Early Morning Pipe Tobacco,

Tobacco is called Nicotiana tabacum in scientific language and English were to make huge profits by selling it just as they did by selling illegally opium produced in Bihar India to Chinese people.

The opium trade had two effects which favored English to defeat the Chinese and dictate the terms in future trade of Silk. These were making the Chinese people addicts and siphoning of the money from China. Anyway we are talking about tobacco.

Original people of the Americas were already growing it when the colonizers got foothold there. It originated in the Andes mountains in South America. It was not only smoked but also used in ceremonies and as a medicine. They smoked it through pipes.

It was Mr. John Rolfe who was one of the first English colonists in Jamestown, Virginia which was founded in 1607. He introduced the sweeter Caribbean tobacco to Virginia. Heavily forested island of Barbados were cleared for cultivating the tobacco. Tobacco was the most profitable export from mainland North America before cotton was established, and from the Caribbean before sugar took over.

Tobacco cultivation requires lots of hard work. Many diseases which were unknown to Americans came along with Europeans and reduced the local population. This made the English to capture the Africans and sell them as farmhands in America.

Tobacco became very popular throughout Europe. Francis Drake first introduced it to England in 1585, and Walter Raleigh made it fashionable. It was seen as a miracle medicine, curing anything from stomach ache to gunshot wounds, and snakebites to bad breath.

Carbon Dating

An element can exist in different forms which have same chemical properties but different atomic weights. They have same atomic mass because number of protons are identical but additional neutrons make then different in weight. Such atoms are called isotopes.

For example carbon which has 6 protons and 6 neutrons have an isotope which have 6 protons but 8 neutrons.  They are represented as C14 and C12. Addition of extra neutrons make them less stable and many of them are radioactive.

The rate at which a particular atom decays is independent of temperature, light or darkness. During decay the atom is trying to achieve state of minimum energy and produces atoms with lower atomic numbers and energy.

The rate of decay is expressed in terms of half life. For example a given weight of C14 atoms will become half in weight in 5600 years precisely.  Then the remaining mass will again take 5600 years to become 1/4 th and so on.

This property has many uses and one of the most popular one is carbon dating to determine the age of wood.

Vegetation absorbs CO2 and the same C14/C12 proportion is found in wood as in the atmosphere as long as the tree is alive. But, after a tree is felled it no longer absorbs CO2 from the atmosphere. Inside the dead wood, the C14 brothers slowly disappear, and are not replaced.

So, a piece of wood from a Pharaoh’s tomb contains a far lower C14/C12 proportion than a tree that has recently been felled.

This type of clock is particularly useful to archaeologists, and allows them to date wood between 200 and 20,000 years old.  The ratio of C14/C12 is measured using a ratio recording mass spectrometer.

Is there life on Mars? Again Microbes hold the key

Earliest life of single cell evolved into 3 branches having distinct traits. The branches further subdivide into more branches on the evolutionary tree of life called Phylogenetic tree of life. The first three branches are called Bacteria, archaea and Eucaryota.

As we can see in this tree, there is a member of archaea family with the name Methanogen. This microbe holds the answer for presence of vast quantities of methane which is trapped inside the ice cages called methane hydrates.

These hydrates are found in Earth’s in permafrost regions having very low temperatures or under the deep sea floor. Water molecules arrange themselves into octahedral cubes in which molecules of many compounds can fit into them.

These are called clathrate compounds. These structures are very fragile and as soon as the overhead pressure is reduced or temperature increases, the structure crumbles and gas is released. So special technology is required to produce the methane from hydrates.

In US, carbon dioxide was pumped into the hydrate layer. It gets substituted into the cages releasing the methane free. It served two important purposes. First the production of fuel gas methane and sequestration of unwanted carbon dioxide which is a greenhouse gas.

These microbes use carbon dioxide and hydrogen to make their food and also generate methane and water.

These microbes are very enterprising. They can use alternative sources of carbon like acetates which are the products formed by another kind of bacteria by breaking the macro-molecules present in the buried organic matter, for their food. One thing these tiny beings hate is oxygen. They work in anaerobic environments like deep buried locations.

Now this microbe is being held responsible for the methane gas found on Mars indicating that there is life on the planet. It means Mars is not a dead planet.

Professor James Kasting said if there is anything alive on Mars at this time in its history, it would probably be some form of microbial life living deep beneath the planet’s surface. Perhaps the most likely form of microbial life is a type of bacteria known as methanogenic bacteria, or methanogens for short.

The CO2 needed by the methanogens could presumably come from the atmosphere. The H2 could come from chemical reactions between water and certain types of rocks, specifically magnesium- and iron-rich basalts. Such rocks are found on certain parts of the seafloor today on Earth. When they react with water, they form minerals called serpentine minerals.

In the process, hydrogen is produced. The reaction that produces methane is thermodynamically favorable, so Methanogens could use the energy released by this reaction to drive their metabolism.

Microbes can make many reactions happen at much lower temperature by changing the path of reactions through enzyme catalysts which these microbes synthesize.

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