Geology of Dasam Falls in Ranchi district of Jharkhand State, India.

 The Dassam Fall is a natural cascade across the Kanchi River.

by

Dr. Nitish Priyadarshi

Geologist

A waterfall is a place where water flows over a vertical drop in the course of a stream or river. Waterfalls are also called cascades. Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it.

The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls. Waterfalls themselves also contribute to erosion.

Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.

Erosion is just one process that can form waterfalls. A waterfall may form across a fault, or crack in the Earth’s surface. An earthquake, landslide, glacier, or volcano may also disrupt stream beds and help create waterfalls. 

Running water always erodes rock, but some rocks are more resistant than others. So a waterfall occurs when geological forces have produced either a sudden change in rock types or a steepening of a gradient where a stream is flowing. With a break in elevation, a stream or river becomes a waterfall.

The Dassam Falls  (also known as Dassam Ghagh) is a waterfall located near Taimara village in Bundu police station of Ranchi district in the Indian state of Jharkhand. Scenery around the falls is very much beautiful. Tourists visiting the Dasham falls get fascinated after viewing the scenery and glory of the place. Tourists from all over India come to visit this beautiful place, which must form an integral part of your Jharkhand itinerary. Natural beauty of the place attracts visitors throughout the year. Tourists can enjoy bathing in the stream, but they are advised to be cautious while taking a dip in the stream.

Dassam means ten. Since ages and till today, whenever the waterfall is seen, ten streams of water can be seen falling. Hence, the name is given. The Dassam Falls is a natural cascade across the Kanchi River, a tributary of the Subarnarekha River. The water falls from a height of 44 metres (144 ft). The sound of water echoes all around the place. Dassam Falls at one of the edges of the Ranchi plateau is one of the many scarp falls in the region.

The Dassam Falls is an example of a nick point caused by rejuvenation. Knick point, also called a nick point or simply nick, represents breaks in slopes in the longitudinal profile of a river caused by rejuvenation. The break in channel gradient allows water to fall vertically giving rise to a waterfall.

Geology of Chota Nagpur Plateau:

The Chota Nagpur Plateau is a plateau in eastern India, which covers much of Jharkhand state as well as adjacent parts of Odisha, West Bengal, Bihar and Chhattisgarh. The Indo-Gangetic plain lies to the north and east of the plateau, and the basin of the Mahanadi River lies to the south. The Chotanagpur Plateau (22°-25° 30'N and 83°47'-87° 50'E) covering an area of 87,239 sq. km includes Ranchi, Hazaribagh, Singhbhum, Dhanbad, Palamau, Santhal Parganas (Jharkhand) and Purulia dis­tricts (West Bengal). It is composed of Archaean granite and gneiss rocks with patches of Dharwar rocks (phyllite, mica-schists).

The Chota Nagpur Plateau of Jharkhand state is a continental plateau - an extensive area of land thrust above the general land. The plateau has been formed by continental uplift from forces acting deep inside the earth. The Gondwana substrates attest to the plateau's ancient origin. It is part of the Deccan Plate, which broke free from the southern continent during the Cretaceous to embark on a 50-million-year journey that was violently interrupted by the northern Eurasian continent. The northeastern part of the Deccan Plateau, where this ecoregion sits, was the first area of contact with Eurasia.

Chotanagpur consists of a series of plateaus standing at different levels of elevation; the highest general elevation of about 1100 m in the mid-west­ern portion known as the Pat lands. From here the land descends in all directions in a series of steps particularly towards the east until it merges gradu­ally with the Lower Ganga Plain. The sharp break in slope are marked by steep scarps where the rivers like Barakar, Damodar, Subamarekha north and south Koels have carved out deep gorges and water­falls. The most characteristic features of relief are revealed in the Hazaribag and Ranchi plateaus standing at same general elevation (600 m) but separated by the Damodar trough (Permo-Triassic trough fault).

Water falls of Ranchi plateau.

It is the largest part of the Chota Nagpur Plateau. The elevation of the plateau land in this part is about 700 metres (2,300 ft) above mean sea level. The general topography is undulating. The Ranchi plateau gradually slopes down towards south-east into the hilly and undulating region of Singhbhum (earlier Singhbhum district or what is now Kolhan division. The plateau is highly dissected. Damodar River originates here and flows through a rift valley. To the north it is separated from the Hazaribagh plateau by the Damodar trough.To the west is a group of plateaux called pat.

There are many waterfalls at the edges of Ranchi plateau where rivers coming from over the plateau surface form waterfalls when they descend through the precipitous escarpments of the plateau and enter the area of significantly lower height. The North Karo River has formed a 17 metres (56 ft) high Pheruaghaugh Falls at the southern margin of Ranchi plateau. Such falls are called scarp falls. Hundru Falls (75 m) on Subarnarekha River near Ranchi, Dassam Falls (44 m) on Kanchi River, east of Ranchi, Sadni Falls (60 m) on Sankh River (Ranchi plateau) are examples of scarp falls. Sometimes waterfalls of various dimensions are formed when tributary streams join the master stream from great height forming hanging valleys. At Rajrappa (10 m), the Bhera river coming over from the Ranchi plateau hangs above the Damodar River at its point of confluence with the latter. The Jonha Falls (25.9 m) is another example of this category of falls. In fact the Gunga River hangs over its master stream, Raru River (to the east of Ranchi city) and forms the said falls.

Formation of Waterfalls in Ranchi Plateau.

The waterfalls of Ranchi plateau including Dasam falls are due to disturbances in late geological age. The Ranchi plateau (or the whole of Peninsular India) believed to have undergone uplift as the side effects of the Himalayan orogeny particularly during the late Tertiary. As the streams descend they are marked by waterfalls.

The Chotanagpur Plateau is made up mainly of Precambrian rocks but has witnessed uplifts synchronously with Himalayan uplift in the Cenozoic.

Some times, waterfalls of varying dimensions are formed when the tributary streams join their master streams from great height forming hanging valleys. In other words, hanging valley falls are formed when the level of the junction of the tributary streams is much higher than the level of the main valley of the master stream. The Rajrappa falls ( 10 m.) at the junction of the Bhera river and the receiving Damodar river (located to the north of Ranchi city) is a typical example of hanging valley waterfalls as the Bhera river after coming from over the Ranchi Plateau hangs above the Damodar river as its confluence with the latter. The Gautamdhara or Johna falls ( 25.9 m.) is another example of this category of falls. In fact, the Gunga river hangs above its master stream, Raru river, ( to the east of Ranchi city) and forms the said falls.

Some falls of Ranchi plateau comes under knick point falls. The breaks in channel gradient caused by rejuvenation are called knick points or heads of rejuvenation. These breaks in channel gradient or knick points denote sudden drops of elevation in the longitudinal profile of the rivers and allow the water to fall down vertically giving birth to waterfalls of varying dimensions. Hundru falls ( 76.67 m) on Subarnarekha river ( near Ranchi city), Johna or Gautamdhara falls at the confluence of Raru and Gunga rivers (to the east of Ranchi). Dasam falls ( 39.62 m and 15. 24 m ) on Kanchi river (east of Ranchi) are the examples of knickpoint falls.

Geology of Dasam falls:

 

Surface rocks surrounding the area are highly smooth. This is due to abrasion. Abrasion is the mechanical scraping of a rock surface by friction between rocks and moving particles during their transport by wind, glacier, waves, gravity, running water or erosion. This phenomenon is active there from millions of years.

Ptygmatic folding of quartzo-feldspathic veins are prominent on the Precambrian (granite-gneiss) rocks of the area.

The ptygmatic folding term is now used essentially for highly contorted quartzo-feldspathic veins found in areas of intense metamorphism and granitisation. Their origin has been a matter of controversy, two different theories have been put forward 1.the veins were originally intruded as flat sheets and the folding is due to deformation of the host rock. 2. Folding took place during the process of injection, which occurred under special circumstances.

It is possible to demonstrate experimentally that material being injected into a weaker host material will develop ptygmatic folding, if it encounters a more rigid mass. This is clearly what happens when ptygmatic veins are formed in granitised or migmatic materials.

 Fig. Ptygmatic folding in rocks of Dasam falls.

Fig. Quartzo-feldspathic intrusion.

Fig. Faulting in the rocks of Dasam Falls.

There are also many potholes in the rocks of  Dasam falls area. Potholes are the kettle-like depressions in the rocky bed of streams. The stream beds in Ranchi plateau are frequently dotted with potholes. Potholes are due to localized drilling action of rock fragments. Where there is an originally minor depression the water of the stream will undergo swirling and the dancing rock fragments will grind against the side and bottom of the depression which will undergo gradual enlargement in perimeter and depth.

  Fig. Potholes in the rocks of Dasam Falls.

Potholes develop particularly in coarse-grained rocks like sandstone or weathered granite

( as in Dasam Falls). In recently uplifted areas like Dasam falls the supply of the boulders or angular rock fragments encourages potholing. The original minor depression could result from local lithological weakness of the rock or joint intersection or the erosion of a local rock piece. The hollow begins to arrest rock fragments.

  

Reference:

Ahmad, E. 1985. Geomorphology. Kalyani Publishers, New Delhi.

Mahadevan, T.M. 2002. Geology of Bihar and Jharkhand. Geological Society of India, Bangalore.

Singh, S. 1994. Physical Geography. Prayag Pustak Bhawan, Allahabad, India.

Rock paintings dating back thousands of years ago have been found on the hill in Ranchi city, India.

Hand Print was found in a rock shelter.

By

Dr. Nitish Priyadarshi

Fig. Hill near Ranchi where Rock painting was found.

A few days ago, during my geological trip to the near by hills in Ranchi city of Jharkhand state of India, I had the opportunity to see rock art for the first time in the city. These rock paintings were found on a hill some 5 kms North of Ranchi city. This hill is composed of granite gneiss rocks. Earlier I saw such paintings far away from the Ranchi city in the villages or in remote areas during my field studies. Fascinated by the detail of their making, I chose them as the subject with geology.  Currently, as a researcher in Geology, I am elaborating on this topic further by studying the engravings of such paintings on the rocks of Ranchi Plateau. There are abstract of geometric symbols, parallel lines, and fence-like patterns. Other symbols hand- and footprints, dancing images etc. Most of the symbols were drawn with great care and were obviously arranged with some purpose. So far it is it is impossible to decode their meaning and cultural significance, but undoubtedly those symbols were once blessed by magic and in the painter’s view therefore possessed supernatural force.

In the hill few big hand prints were found in a rock shelter. One was prominent and others have faded. It resembles to female hand. According to local people these hand prints belongs to Goddess Durga.

Fig. Hand prints on the hill near Ranchi

Fig. Author on the hill with rock paintings.

Many experts have analyzed hand prints at caves in Spain and France and found most of them were female. Red Ochre paint has been used in these handprints which nearly date back to 15,000 to 20,000 years. This shows us that the paintings belong to the Latmos Rock Paintings group. The Latmos Mountains in the hinterland of the west coast of Turkey near Milet were one of the holy mountains of Asia Minor.

Similar rock paintings have previously been found in the Beşparmak Mountains, Bafa Lake and its environs, all of which are located in an area divided between Muğla’s Milas district and Aydın’s Koçarlı and Söke districts. Beşparmak Mountains is a ridge of many spurs running in an east-west direction along the north shore of the former Latmian Gulf on the coast of Caria, which became part of Hellenised Ionia. The city of Latmus, located on the south slopes of Mount Latmus 25 kilometres (16 mi) east of Miletus. Miletus was an ancient Greek city on the western coast of Anatolia.

Such similarity in hand prints gives a conclusion that the civilization in both the areas might have been same.

Prehistoric painters used the pigments available in the vicinity. These pigments were the so-called earth pigments, (minerals limonite and hematite, red ochre, yellow ochre and umber), charcoal from the fire (carbon black), burnt bones (bone black) and white from grounded calcite (lime white). Prehistoric handprints span all continents and began appearing on rock walls around the world at least 30,000 years ago.

Fig. Rock painting similar to geometrical lines.

Other rock art found near hand prints is like some geometrical lines with few parallel lines. It looks like an irregular-shaped net. Experts compare it with local Sohrai Art made by tribes of Jharkhand. But to me it looks like some ancient village map demarcating the boundaries or some language or some astronomical information which is still to be understood. These paintings are important in terms of world cultural heritage. 

10,000 year-old-rock paintings was also found in Tangar Basli block some 40 kms from the state capital Ranchi is now under threat. These rock paintings resembles to rock paintings of rock art of Great Canyon Region.

Threat is from the stone quarrying due to which these paintings have been exposed to the flying stone dust and open atmosphere. Most of the paintings now have been faded. Drawings are made on granite and granite gneiss rocks. In these paintings red ochre has been used. Dancing is the major subject of all these paintings. We now recognize that they did not simply live in caves and hunt animals. They also participated in a full cultural lifestyle, social events with friends and neighbors.

   

Fig. Rock paintings of Tangar Basli near Ranchi

Such rock art in Ranchi and other parts of Jharkhand has the great similarity with little difference in rock art of other countries. It seems that the single civilization was spread all over the earth.

Geology of Ranchi Plateau provides enough cliff faces and domes perfectly suitable to create rock-cut architecture. Granite, granite gneiss and schist are widespread in Ranchi Plateau - these rocks can be tough and time resistant, thus providing ideal basis for paintings. Shade of deep cave and skilful protection from seeping water provide ideal protection from elements.

All of these markings are referred to as "Rock Art." People worldwide have been producing rock art for thousands of years. Some of their messages, produced thousands of years ago, can still be seen today. The oldest are usually found in rock shelters and caves where they are protected from the elements. However, in arid climates some examples of rock art have persisted for ten to fifteen thousand years, depending upon how the art was produced, the direction that it faces and the type of rock used as a "canvas."

Ancient petroglyphs do not have "signatures" because they were produced before written words were invented. So, they cannot be attributed to a specific person. However, petroglyphs can sometimes be attributed to a specific group of people who inhabited or passed through the area where the petroglyphs occur.

Now all these paintings in Ranchi and other parts in the district are under threat due to natural weathering and interference of people.

Reference:

http://www.crystalinks.com/petroglyphs.html

http://www.livescience.com/14149-mysterious-ancient-rock-art-nile-river.html

http://www.hurriyetdailynews.com/ancient-paintings-discovered-in-aydin.aspx?pageID=238&nID=46107

http://geology.com/articles/petroglyphs.shtml

How the Waterfalls are formed? With special reference to Ranchi plateau in Jharkhand State of India.

The waterfalls of Ranchi plateau are due to disturbances in late geological age.

By

Dr. Nitish Priyadarshi

Fig.1 Johna falls is the example of waterfalls resulting from upliftment. 

Fig.2 Dasam falls formed due to upliftment.

 Fig. 3 Hundru falls is the example of knickpoint falls.

A waterfall is a place where water flows over a vertical drop in the course of a stream or river. Waterfalls are also called cascades. Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it.

The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls. Waterfalls themselves also contribute to erosion.

Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.

Erosion is just one process that can form waterfalls. A waterfall may form across a fault, or crack in the Earth’s surface. An earthquake, landslide, glacier, or volcano may also disrupt stream beds and help create waterfalls. 

Running water always erodes rock, but some rocks are more resistant than others. So a waterfall occurs when geological forces have produced either a sudden change in rock types or a steepening of a gradient where a stream is flowing. With a break in elevation, a stream or river becomes a waterfall.

Geology of Chota Nagpur Plateau:

The Chota Nagpur Plateau is a plateau in eastern India, which covers much of Jharkhand state as well as adjacent parts of Odisha, West Bengal, Bihar and Chhattisgarh. The Indo-Gangetic plain lies to the north and east of the plateau, and the basin of the Mahanadi River lies to the south. The Chotanagpur Plateau (22°-25° 30'N and 83°47'-87° 50'E) covering an area of 87,239 sq. km includes Ranchi, Hazaribagh, Singhbhum, Dhanbad, Palamau, Santhal Parganas (Jharkhand) and Purulia dis­tricts (West Bengal). It is composed of Archaean granite and gneiss rocks with patches of Dharwar rocks (phyllite, mica-schists).

The Chota Nagpur Plateau of Jharkhand state is a continental plateau - an extensive area of land thrust above the general land. The plateau has been formed by continental uplift from forces acting deep inside the earth. The Gondwana substrates attest to the plateau's ancient origin. It is part of the Deccan Plate, which broke free from the southern continent during the Cretaceous to embark on a 50-million-year journey that was violently interrupted by the northern Eurasian continent. The northeastern part of the Deccan Plateau, where this ecoregion sits, was the first area of contact with Eurasia.

Chotanagpur consists of a series of plateaus standing at different levels of elevation; the highest general elevation of about 1100 m in the mid-west­ern portion known as the Pat lands. From here the land descends in all directions in a series of steps particularly towards the east until it merges gradu­ally with the Lower Ganga Plain. The sharp break in slope are marked by steep scarps where the rivers like Barakar, Damodar, Subamarekha north and south Koels have carved out deep gorges and water­falls. The most characteristic features of relief are revealed in the Hazaribag and Ranchi plateaus standing at same general elevation (600 m) but separated by the Damodar trough (Permo-Triassic trough fault).

Water falls of Ranchi plateau.

It is the largest part of the Chota Nagpur Plateau. The elevation of the plateau land in this part is about 700 metres (2,300 ft) above mean sea level. The general topography is undulating. The Ranchi plateau gradually slopes down towards south-east into the hilly and undulating region of Singhbhum (earlier Singhbhum district or what is now Kolhan division. The plateau is highly dissected. Damodar River originates here and flows through a rift valley. To the north it is separated from the Hazaribagh plateau by the Damodar trough.To the west is a group of plateaux called pat.

There are many waterfalls at the edges of Ranchi plateau where rivers coming from over the plateau surface form waterfalls when they descend through the precipitous escarpments of the plateau and enter the area of significantly lower height. The North Karo River has formed a 17 metres (56 ft) high Pheruaghaugh Falls at the southern margin of Ranchi plateau. Such falls are called scarp falls. Hundru Falls (75 m) on Subarnarekha River near Ranchi, Dassam Falls (39.62 m) on Kanchi River, east of Ranchi, Sadni Falls (60 m) on Sankh River (Ranchi plateau) are examples of scarp falls. Sometimes waterfalls of various dimensions are formed when tributary streams join the master stream from great height forming hanging valleys. At Rajrappa (10 m), the Bhera river coming over from the Ranchi plateau hangs above the Damodar River at its point of confluence with the latter. The Jonha Falls (25.9 m) is another example of this category of falls. In fact the Gunga River hangs over its master stream, Raru River (to the east of Ranchi city) and forms the said falls.

Geological formation of Waterfalls in Ranchi Plateau.

The waterfalls of Ranchi plateau are due to disturbances in late geological age. The Ranchi plateau (or the whole of Peninsular India) believed to have undergone uplift as the side effects of the Himalayan orogeny particularly during the late Tertiary. As the streams descend they are marked by waterfalls. The most important water falls in Ranchi Plateau are the Hundru falls on the Subarnarekha. The structure is granite-gneiss. The main drop is on a nearly vertical. It could be interpreted as due to local faulting because as believed all the scarps in Ranchi plateau are due to successive Tertiary faulting.

The Chotanagpur Plateau is made up mainly of Precambrian rocks but has witnessed uplifts synchronously with Himalayan uplift in the Cenozoic.

According to another concept falls of the plateau are formed due to sudden steeping of slope. This steepening may be caused by the quicker erosion of softer elements below harder rocks at the lower end of which water tumbles ( as on the Bhusur river 300 m., west of Hinoo bridge in Ranchi city).

Waterfalls of varying dimensions are formed due to upliftment of local nature in the courses of the rivers. These waterfalls are obliterated when the rivers regrade their longitudinal profiles. A series of waterfalls on the river along the junction of Palamau upland and the northern flat plain ( Palamau district Jharkhand) are said to have been formed due to orogin of escarpment caused by upliftment of southern Palamau during Tertiary period. Patam falls ( 45.72 m) and Datam falls (30.45 m) on Patam river ( in Bhandaria Anchal, Palamau, Jharkhand) are typical examples of such categories. The waterfalls on the eastern margin of Ranchi Plateau ( e.g. Hundru falls on Subarnarekha river, Dasam falls on Kanchi river, Johna or Gautamdhara falls on Gunga river etc.) are also quoted as the examples of waterfalls resulting from upliftment.

Some times, waterfalls of varying dimensions are formed when the tributary streams join their master streams from great height forming hanging valleys. In other words, hanging valley falls are formed when the level of the junction of the tributary streams is much higher than the level of the main valley of the master stream. The Rajrappa falls ( 10 m.) at the junction of the Bhera river and the receiving Damodar river (located to the north of Ranchi city) is a typical example of hanging valley waterfalls as the Bhera river after coming from over the Ranchi Plateau hangs above the Damodar river as its confluence with the latter. The Gautamdhara or Johna falls ( 25.9 m.) is another example of this category of falls. In fact, the Gunga river hangs above its master stream, Raru river, ( to the east of Ranchi city) and forms the said falls.

Some falls of Ranchi plateau comes under knick point falls. The breaks in channel gradient caused by rejuvenation are called knick points or heads of rejuvenation. These breaks in channel gradient or knickpoints denote sudden drops of elevation in the longitudinal profile of the rivers and allow the water to fall down vertically giving birth to waterfalls of varying dimensions. Hundru falls ( 76.67 m) on Subarnarekha river ( near Ranchi city), Johna or Gautamdhara falls at the confluence of Raru and Gunga rivers (to the east of Ranchi). Dasam falls ( 39.62 m and 15. 24 m ) on Kanchi river (east of Ranchi) are the examples of knickpoint falls.

Reference:

Ahmad, E. 1985. Geomorphology. Kalyani Publishers, New Delhi.

Mahadevan, T.M. 2002. Geology of Bihar and Jharkhand. Geological Society of India, Bangalore.

Singh, S. 1994. Physical Geography. Prayag Pustak Bhawan, Allahabad, India.

 

Why vegetarian animals are fat?

Theory begins some 50 million years back.

By

Dr. Nitish Priyadarshi.

One of my friends suggested me to become non-vegetarian. He gave the interesting example about the benefit of becoming non- vegetarian. He said that all non-vegetarian animals like tiger, cheetah, wolfs are slim compared to vegetarian animals like buffalo, elephant, zebras etc. I started searching the mystery of why vegetarian animals are so fat? Some theories are hidden in pages of time million years back.

Why did some prehistoric animals get so big in the first place? No one knows for sure, but there are lots of theories. One theory begins some 50 million years back.

The past 50 million years appear to have been a time of progressive deterioration. On every vegetated continent, grasses and small hard leaves widened their domain. While certain herbivores accommodated to the new foliage- and evolved the art of eating coarse, fibrous fodder-other species, committed to Eocene and Oligocene ways, died. In many animals, from horses and zebras to rodents, from antelopes to kangaroos, from giraffes to camels, from elephants to pigs, the main food-processing part of the jaw, the cheek teeth, became larger in over-all height and riddled with complex slicing edges. An increase in tooth height, called hypsodonty (high tooth) is typical of animals that harvest greenery close to the ground-mainly fibrous grasses in open territory which is generally poor in nutritional value.

Any animal committed to such a diet must eat an enormous quantity. This requires both a large gut and a large body capable of handling masses of grass and other fibrous plants. Long –distance travel allowed access to such volumes of vegetation, mowed and chewed as the animal walked along. After the Eocene, many lineages of animals evolved to a large size, formed social herds, and modified their limb bones in ways that allowed wide and rapid movements over open terrain.

The other theory says being larger can provide many evolutionary advantages—bigger animals are less vulnerable to predators and can compete more assertively for resources. The existence of bigger herbivores also means that carnivorous animals have to grow in order to be effective hunters. A species' size may also shift in response to environmental factors. In cold climates, a bulky frame can be an asset to warm-blooded animals—the bigger they are, the better they retain heat. The opposite is true for cold-blooded animals—in a warm climate, a bigger mass can help insulate an animal and keep it from overheating. Scientists suggest that some plant-eating dinosaurs and other animals might have gotten so big because the foliage in that era was extremely tough and woody: A larger body frame meant a longer digestive tract and more time for bacteria to do its work, allowing the dinosaur to extract as much nutritional value as possible from each bite.

 

Venus shining above Ranchi city, India.

People confused it with flying object or a satellite.

By

Dr. Nitish Priyadarshi

Venus planet near to Earth.

Few of my friends call me up to know about the bright object in the sky above Ranchi city. They confused it with some flying object or a satellite. It is Venus, I told them. It’s the planet which is easily visible at nightfall around the world in early November. Venus continues to draw all eyes to the western sky after sunset. Observers have been watching the bright planet for many weeks, although it seems that a fairly large percentage is not quite sure exactly what they have been looking at. Venus has increased noticeably in recent days. Venus beams mightily in the west at dusk, as seen from across the Earth. You can’t miss it. It sets roughly two-and-one-half-hours hours after sunset at mid-northern latitudes in early November and close to three hours after the sun by the month’s end. Venus! It’s the beautiful “evening star.”

The best time to observe Venus is actually in the early morning or early evening before the sky gets too dark. This is because Venus is so bright that it can actually be more difficult to see its features with the large contrast between it at the night sky, and it is best to catch it with some twilight behind it.

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has no natural satellite. It is named after the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky. Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, gravity, and bulk composition (Venus is both the closest planet to Earth and the planet closest in size to Earth). However, it has also been shown to be very different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. Venus may have possessed oceans in the past, but these would have vaporized as the temperature rose due to a runaway greenhouse effect.