Tuesday, August 31, 2010

Rare earths elements are in increasingly short supply as world demand surges.

Jharkhand State of India can play major role in Rare Earth Elements production.
Dr. Nitish Priyadarshi

China has been steadily reducing export quotas since 2005 for rare earth elements, which consist of 17 metals used in crucial new green technologies like hybrid cars, wind turbines and superconductors, as well as in missile guidance systems and mobile phones.

According to Chinese experts, “Mass extraction of rare earth will cause great damage to the environment and that's why China has tightened controls over rare earth production, exploration and trade,".

Overseas buyers have expressed concern about China's policies to restrict rare earth exports, which have driven up global prices. Rare earths are in increasingly short supply as world demand surges, with industry officials predicting a global shortfall of 30,000 to 50,000 tonnes by 2012.

The automobile industry uses tens of thousands of tons of rare earth elements each year, and advanced military technology depends on these elements, too. Lots of "green" technologies depend on them, including wind turbines, low-energy light bulbs and hybrid car batteries. In fact, much of western civilization depends on rare earth elements such as terbium, lanthanum and neodymium.

If that happens, the western world will be crippled by the collapse of available rare earth elements. Manufacturing of everything from computers and electronics to farm machinery will grind to a halt. Electronics will disappear from the shelves and prices for manufactured goods that depend on these rare elements will skyrocket.

Seeing the possible scarcity of rare earth elements in coming future, India can play major role in REE production. Especially Jharkhand and West Bengal State, which has the potential of good REE in its rocks and inland placers.

Rare earth elements or rare earth metals are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium, and the fifteen lanthanides. Scandium and yttrium are considered rare earths since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties. Rare earth minerals occur chiefly in association with alkalic plutons and in placers derived from them. Specific minerals mined for their rare earth or thorium content are monazite and bastnaesite. Despite their high relative abundance, rare earth minerals are more difficult to mine and extract than equivalent sources of transition metals (due in part to their similar chemical properties), making the rare earth elements relatively expensive.

Common Properties of the Rare Earths.

  1. The rare earths are silver, silvery-white, or gray metals.
  2. The metals have a high luster, but tarnish readily in air.
  3. The metals have high electrical conductivity.
  4. The rare earths share many common properties. This makes them difficult to separate or even distinguish from each other.
  5. There are very small differences in solubility and complex formation between the rare earths.
  6. The rare earth metals naturally occur together in minerals (e.g., monazite is a mixed rare earth phosphate).

Indian reserves are predominantly of monazite ore. Monazite contains about 60% of the rare earths of the cerium group expressed as oxide plus an average 7.2% thorium and minor yttrium. It is yellowish to reddish brown mineral. In India, it occurs in commercial concentrations in beach sands.

The pegmatite veins in crystalline rocks contain a few rare earth minerals as their accessory constituents. The most common of these are columbite and tantalite, torbernite, aeschynite, allanite etc. which occur in the mica pegmatite of Hazaribag in Jharkhand State of India. Other places in India are Nellore, Andhra Pradesh and Tranvancore in Kerala and Rajasthan. Gadolinite is found associated with cassiterite in a tourmaline pegmatite in Palanpur; and molybdenite in the crystalline rocks of Chota Nagpur in Jharkhand state.

Geological Survey of India (GSI), during field season 1993-94, carried out detailed study of the north Singhbhum shear zone, in Jharkhand State, with a view to establishing mineral potential including rare earth elements (REE). The results obtained, being not encouraging, similar study in parallel north Purulia shear zone, which is also known as Jhalda shear zone is to be taken up. It extends westward in Ranchi district and is associated with apatite and magnesite mineralization. Recently, some carbonatites with high REE values are reported from this shear zone in West Bengal in India.

In the course of specialized thematic mapping of Chota Nagpur gneissic complex in parts of West Bengal, a few rare metal pegmatites bodies have been identified .Chemical data of these samples show high cesium (1.72 to 13.73%), rubidium (0.27 to 0.33%) and lithium (0.07 to 1.36%).

The world reserve base in terms of rare earth oxides content is estimated at 110 million tones. Although a certain degree of rare earth’s processing exists in a number of countries, the industry is dominated by a few main players like USA, France, Japan and China.

Mineable concentrations of source elements of the rare earth group of metals are uncommon. Bastnaesite is mined extensively in China and the USA. Monazite is recovered largely as a by-product of processing heavy mineral sands in various parts of the world, primarily Australia and India.

Among the inland placer deposits containing heavy mineral, there are two appreciable concentrations of monazite, which are located in Ranchi plateau of Jharkhand and the Purulia planes of West Bengal in India. These occurrences cover an area of about 608 km2 , forming a thin cover of an average depth of about 50 cm (which may be locally up to 2 m). These deposits have been formed due to the weathering and erosion of Precambrian gneisses and schists, intruded by pegmatites and porphyritic granits, which are rich in monazite and other associated heavy minerals.

The rare earths are constituents of more than 100 minerals, but only few are recovered. Bastnaesite, monazite, xenotime and rare earth-bearing clays are the principal sources of rare earth supply in the world.

REE are strategic resources upon which entire nations are built. In many ways, they are similar to rubber -- a resource so valuable and important to the world that many experts call it the "fourth most important natural resource in the world," right after water, steel and oil. Without rubber, you couldn't drive your car to work or water your lawn. Many medical technologies would cease to work and virtually all commercial construction would grind to a halt.

Monday, August 23, 2010

Climate of the world is changing.

Climate is changing, carbon dioxide is increasing, and Earth is getting hotter.
Dr. Nitish Priyadarshi
Mumbai floods
First it was Bombay floods, then Kosi floods, Punjab floods, Rajasthan floods, Leh floods, Jharkhand drought (all in India). Now it is Paksitan floods, China flash floods and landslides, boiling of Moscow, forest fires in Russia, Bolivia and Portugal, and there are lots more to say and write. Millions affected, thousands died, no ending disaster. Climate of the world is changing. What would you think? Yes its climate change or in other broad definition its global warming.

If we take the case of drought in Jharkhand State of India, it is very unusual. Other than some pockets of the state, Jharkhand never passed through severe droughts. Rainfall was sufficient all around the year. But from last one year rainfall pattern has changed. Farmers are still waiting for the sufficient rainfall. Agriculture scientists are worried. Monsoon Clouds have changed their way from Bay of Bengal.

Scientists feel that carbon dioxide is rising, so temperature is also rising. And they conclude that, all these disasters are the out come of Global Warming and El Nino. To larger extent it’s true. Climate is changing worldwide. Where it is use to rain heavily now passing through droughts.

All the three factors (air temperatures, air pressure and humidity) which affect weather are changing. Temperature is rising so the humidity. Humidity is the amount of moisture that is present in the air. We know that the amount of moisture in the air affects the climate and weather greatly. If there is a lot of moisture in the air, it is likely to rain.

The cloud become bigger and bigger, heavier and heavier. Finally, the water droplets become so heavy, that they fall as heavy to very heavy rain as it happened in Leh and part of Uttrakhand states in India, where hundreds died this year due to cloud brust.

Heating of Arabian Sea has resulted in the disaster floods in Mumbai, now in Rajasthan and Gujrat and in neighbouring country Pakistan.

Heavy rains have also affected Delhi, Mumbai and other metro cities of India. Other than climate change, “Urban heat island effect”, may be the other cause of these heavy showers. Scientists have found that urban areas are 1 to 5.5 degree centigrade hotter than the countryside.

The summer of 2002 saw widespread flooding over much of central and western Europe, from Romania to Russia. The city that was most badly affected and was certainly most in the news was the Czech capital, Prague. In August of that year heavy rainfall from a slow-moving frontal system which also affected much of the rest of Europe. The river Vltava rose ominously, forcing the country’s president to enforce an evacuation of 40,000 people.

Scientists discovered that North America, Europe, Asia and Australia had the highest rate of warming during the 20th century. These places experienced temperature rises of between 0.5 and 0.6 degree centigrade from 1950 to 1999. Industrial activity coupled with deforestation in these parts of the world is high. Oil refineries and factories that burn fossil fuels for making electricity produce air pollutants, such as sulfur dioxide and carbon dioxide. As carbon dioxide is greenhouse gas, it traps heat and warms the earth’s surface.

Climate is changing, carbon dioxide is increasing, and Earth is getting hotter. We are under the threat of worst changes of nature. Scientists have found that the Earth’s temperature increased up to 0.6 degree centigrade during the 20th century. They believe that one of the main causes of this global warming is the increase in green house gases in the atmosphere. They estimate that if the amount of green house gases continues to increase, the earth’s temperature will continue to rise too, perhaps by up to 3.5 degree centigrade over the coming decades.

Tuesday, August 17, 2010

Concept of environment in ancient Indian Philosophy.

Indian thought perceives that there is life in all kinds of things.
Dr. Nitish Priyadarshi

Worldwide awareness of the need for protection of the environment and prevention of ecological disaster has taken root, very slowly, only in the past 50 years or so.

Although human beings are considered the most intelligent life form on earth, they are responsible for most of the damage done to planet earth.

In India and elsewhere, as awareness of clean water needs, pollution of air, water and soil, global warming, species extinction, etc creates urgency for action, religious thinkers and activists have begun to reflect on how the values of Indian tradition might contribute to fostering greater care for earth’s ecology.
Environmental in Indian thought is not conceived as a physical, lifeless entity- it is very living mechanism where humans are one of the many living creatures. There is also a great emphasis on adaptation as one of the guiding principles for an interaction between human and non- human world.

It has been argued by ancient Indian philosophers that man being an intelligent creature should have the protection of environment as one of the fundamental duties. The fragility of the environment has also been carefully stressed in such discourses.

The principal cosmic-vision is fully integrated in two different but related traditions- the oral and textual. While the reflections of the oral tradition are more focused on practice, the textual tradition offers a complete and systemic analysis of the universe.

The Indian textual tradition assumes that, like the rest of the material world, man is made of elements which at death disintegrate and dissolve into nature. At the most general levels there are nine tatvas or elements; Earth, Water, Fire, Air, Sky, Time, directions, Mind and Soil. Indian mythology explains that elements originate in phases. Water, Earth and sky come first; aquatic animals and birds second; land third; air or wind fourth and finally fire.

Indian thought explains Environment as a given entity which is transcendental in nature. It perceives that there is life in all kinds of things, it might be biotic or non-biotic material. There is greater emphasis on mutual dependence where living in isolation was not possible. Environment has been perceived as a friendly abode.

It was considered very good to live in forest where one can experience environment in its purest form. Living in urban centers, which is natural- man made living, was given secondary position. It was perceived that nature can satisfy everybody’s need if one maintains harmony with the given environment.

Even in different stages of human life in Hindu philosophy, shifting to forest in older age was given importance which is commonly known as “Vanaprastha”. A Vanaprastha (Sanskrit ) is a person who is living in the forest as a hermit after partially giving up material desires.

This word is generally used to denote a particular phase of life in the Vedic ashram system when a person is between the ages of 50 and 74. In this phase of life, the person is in a retreat from worldly life. He lives away from the city, in a jungle as a hermit, with as little material possessions as possible. This stage denotes a transition phase from material to spiritual life.
When a householder is considered to be older or advanced in years, perceiving his skin become wrinkled, his hair turns gray, and has grandchildren, the time is said to have come for him to enter the third stage of life, or vanaprastha. It is said that he should now disengage himself from all family ties, except that his wife may accompany him, if she chooses.

Ancient Indian felt Brahman (not caste) presence in everything around them. Since these divine forces sustained all living creatures and organic things on this earth, to please God, they felt they must live in harmony with His creation including earth, rivers, forests, sun, air, and mountains. This belief spawned many rituals that are still followed by traditional Indians. For example, before the foundation of a building is dug, a priest is invited to perform the Bhoomi Pooja in order to worship and appease mother earth and seek forgiveness for violating her. Certain plants, tries and rivers were considered sacred, and worshipped in festivals.

What oral tradition says?
Oral traditions form the basic method by which we come to know about the knowledge which has not been codified. They also help us to understand those societies, for which we have very limited textual information. Day-to-day human conversation carries the glimpses of ancient past.
In oral tradition in India, environment has been perceived as a living being which breathes, feels, protects etc. Environment is a friendly entity.

The animals and forms are one of the basic components of tales and oral tradition in India had created. Various attributes of animals were identified and were used as if they are natural characteristics. Plant life provided the base of different stories. It was always kept in mind that human survival was possible only with the conservation of entire flora and fauna. It is also reflected in the religious practices as different animals and plants were worshipped at different times so as to ensure their survival.
Environment in Philosophical treatises-
The Indian textual tradition conceives environment as a system with life which has synchronized the complex inter-relationship of numerous living and non-living entities. Even the abiotic world has been perceived as a living creature with a soul. It is a very significant concept as it placed man as equal to every other element of our environment. The Indian thought greatly emphasizes upon a very cordial relationship among all the elements of our world. To highlight the importance of various components of our environment, various rituals have been institutionalized. These rituals ensured that we treated even the non-living world with great care and maintain a harmony.

For example fire is conceived as messenger of God. Earth has been considered as mother goddess. Sky is worshipped as father. Earth worship manifested itself even in stone worship.
The tales of Panchtantra also highlight the special position which is given to living world. Animals are given human characteristic of not only language but also faculty of feelings and rationality. It tries to give lessons to mankind by highlighting the problems through animal world’s characteristics. Different attributes of animals have been identified and are very beautifully utilized in these tales. Cow is worshipped. Trees are worshiped. Various animals are allotted to different Gods and Goddesses as their mode of transportation to highlight their utility and to enhance their position.

Vedas, Upanishads, Puranas, and other scriptures give a detailed description of trees, plants and wildlife along with their importance to the community. Trees have considered as an essential part of dwelling in Indian homes. Significance of plants and trees to human life is further exemplified in Varah Puran which advocates regular plantation as a means to achieve heaven. In Matsyapurana and Padmapurana also there is description of great plantation ceremony- Vriksha Mahotsava (Tree Festival). In Matsyapurana plantation of a tree has been equated with progeny of ten sons.

Indians believed that humans, gods and nature were integral parts of one organic whole. Ancient Indian writers, later on, personified each of the divine force as a Devata or deity worthy of reverence and worship. Even Charvaka, the atheist philosopher of ancient India, who totally rejected Vedas, the Hindu scriptures, considered the principles of Vayu (air) Bhumi (earth), Jala (water), Agni (fire) as important factors in regulating the lives of humans, animals and plants.

Hymn IX of Book 10 of Rig Veda is dedicated to Water. The hymn recognizes the life giving ability of water, not only physically but also spiritually. The prayer concludes that plentiful supply of pure water be always available.
Here is a hymn from Isha Upanishad:
"Everything in the universe belongs to the Supreme God. Therefore take only what you need, that is set aside for you. Do not take anything else, for you know to whom it belongs".
Isha Upanishad also says: “Resources are given to mankind for their living. Knowledge of using the resources is absolutely necessary.”
The holy scripture Bhagavatam (Volume 2, Chapter 1, Verses 32-33) says:
"The air is His breath, the trees are the hairs of His body, The oceans His waist, the hills and mountains are His bones, The rivers are the veins of the Cosmic Being (Brahman), His movements are the passing of ages".

Indian philosophical thought also highlights the numerous species of flora and fauna and their special position vis-à-vis environment and Master living creature. This totalistic view is a great achievement of the Indian philosophy.

Wednesday, August 11, 2010

Flood devastation in Pakistan.

Assistance requested by The International Rescue Committee (IRC).
Dr. Nitish Priyadarshi

The worst flooding in Pakistan's history has now affected more than four million people and left at least 1,600 dead, says the UN.

While floods in the north-west began to recede, the vast body of water has been moving down the country into new parts of Punjab and menacing Sindh province.

All wells have been contaminated and water-borne diseases are spreading, officials say.
The region is midway through monsoon season and more rain is forecast.

The number of affected districts in Punjab has reached seven, while 350,000 people have been moved from neighbouring Sindh province, most of which is on high alert, the United Nations said.

In Punjab, known as Pakistan's "breadbasket" for its rich agriculture, more than 1,300 villages have been affected and at least 25,000 homes destroyed, said disaster relief officials in the province.

In the worst-affected areas, small villages have been submerged.

In large tracts of Kot Addu and nearby Layyah, water levels were so high only treetops were visible.

The 2010 Pakistan floods began in July 2010 after record heavy monsoon rains. The Khyber Pakhtunkhwa province of Pakistan was worst affected. At least 1,600 people were killed, thousands were rendered homeless, and more than fourteen million people were affected. Estimates from rescue-service-officials suggest the death-toll may reach 3,000 victims. According to a recent estimate of United Nations, the number of people suffering from these massive floods in Pakistan exceeds 13.8 million, which is more than the combined total of the 2004 Indian Ocean tsunami, the 2005 Kashmir earthquake and the 2010 Haiti earthquake.

The floods were caused by monsoon rains, which were forecast to continue into early August and were described as the worst in this area in the last 80 years. The Pakistan Meteorological Department said that 300 mm (12 inches) of rain fell over a 36-hour period and more was expected. So far as many as 500,000 or more people have been displaced from their homes. Manuel Bessler, head of the UN Office for the Coordination of Humanitarian Affairs, stated that 36 districts were involved, and 550,000 people were affected, although later reports increased the number to as high as a million affected.
Officials have warned that the death-toll could rise as many towns and villages are not accessible and communications have been disrupted. In some areas, the water-level was 5.5 m (18 ft) high and residents were seen on roof-tops waiting for aid to arrive. At least 45 bridges and 3,700 houses were swept away in the floods. The Karakoram Highway, which connects Pakistan with China, was closed after a bridge was destroyed. The ongoing devastating floods in Pakistan will have a severe impact on an already vulnerable population.
Mean while United Nations has criticized the world nations for responding slowly, despite the ferocity and magnitude of disaster. As of 9 August, only $45 million have been committed, which is far less than several recent natural disasters combined.
The International Rescue Committee contacted me to circulate this information through my blog to help Pakistani people in distress.

The International Rescue Committee (IRC), a global leader in humanitarian assistance, is on the ground providing aid to survivors of the flooding. You can read about their emergency response efforts here [link: http://www.theirc.org/news/irc-ground-flood-ravaged-pakistan-situation-desperate-9144].

The IRC has been providing lifesaving aid in Pakistan for 30 years. they are already working in the areas hit hardest by the floods, including Charsadda, Kohat, Lower Dir, Nowshera, Tank, Mardan and Swat. Last year, many of these same areas were affected by fighting between militants and government forces that uprooted millions of people.
The IRC will also focus on providing clean water, sanitation, shelter and essential supplies to those who have fled the rising waters. With their robust network of local staff and partners already on the ground -- and decades of experience responding to emergencies in Pakistan -- the IRC is well-positioned to help families in dire need.

Tuesday, August 10, 2010

Heat wave killing people in Russia.

Muscovites are dying from extreme heat.
Dr. Nitish Priyadarshi

A polar bear cub looks at an adult polar bear resting with a bucket on its head in the cooling waters of a pool at the Moscow Zoo, as the city experiences a prolonged heatwave
Picture: AP

Muscovites are dying from extreme heat and smoke faster than their bodies can be stored, cremated or buried, and Russians are worried the death toll could be far higher than the official count.
Morgues are overflowing and one crematorium in the Russian capital is working around the clock in three shifts. In Mitino on Moscow's northwest, a note at a crematorium warned that it was not accepting any new orders for cremation.
The crematorium's four furnaces are currently "processing" 49 bodies per day, with cremations every 20 minutes, according to a timetable available at the reception.
As wildfires and a record-setting heatwave continue to pummel Russia Monday, death rates in Moscow are also rising as residents navigate smoke-laden streets and record temperatures.

Heat stroke and complications from air quality have nearly doubled death rates in Moscow, from about 360 deaths a day to about 700, according to Moscow's health department, The Associated Press reported. Carbon monoxide levels are two to three times higher than the level considered healthy.
Many Russians have taken to wearing facemasks when they leave their homes to protect themselves from the smog.
As some people take to the water to beat the heat, a spate of drownings has added to the skyrocketing death toll. Many of those who drowned were drunk, according to the Emergencies Ministry.
The head of Russia's weather service, Alexander Frolov, said this summer's temperatures could be the hottest in up to a millennium."In 1,000 years, neither we nor our ancestors have observed or recorded anything like this sort of heat," he said in televised comments, reported Bloomberg News. About 52 people have been killed by the fires since they began in late July.

A satellite image released by NASA Monday showed large swaths of the region surrounding and south of Moscow experiencing land surface temperatures up to 12 degrees Celsius higher than average temperatures for the same dates between 2000 and 2008.

This NASA image from Saturday shows the coverage of the smoke around the city that's forced airports to delay flights. The red outlines indicate fires that were still burning.

The acrid smog from the fires burning in the countryside dozens of kilometres outside the city is seeping into apartments, offices and even underground into the Moscow metro, forcing Russians to flee the city.

RUSSIAN officials declared a state of emergency as raging wildfires threatened to engulf a major nuclear plant.
It came as leaders were accused of covering up hundreds of deaths from poisonous smog and the country's worst ever heatwave.
Last night the blazes threatened to spread to the Mayak reprocessing plant, in Ozersk in the Urals.
A local official said: "A state of emergency has been introduced in forests and parks due to a complicated fire hazard situation."
The peat bog fires have already threatened the nuclear research city of Sarov.
A record 50 days without rain and heat hitting 38°C (100°F), sparked fires across Russia.


Monday, August 9, 2010

Earth like planets in our universe?

Spotting true Earth-sized planets is challenging with current technology.
Dr. Nitish Priyadarshi

Twinkle, twinkle little star, goes the nursery rhyme, but what scientists are really wanting to find is planet’s similar to our earth.

When scientists confirmed in October that they had detected the first rocky planet outside our solar system, it advanced the longtime quest to find an Earth-like planet hospitable to life.

Rocky planets -- Earth, Mercury, Venus and Mars -- make up half the planets in our solar system. Rocky planets are considered better environments to support life than planets that are mainly gaseous, like the other half of the planets in our system: Jupiter, Saturn, Uranus and Neptune.

We know that earth is a pretty rare planet in our universe. Only a relative handful of planets are rocky and even fewer are in the habitable zones of their stars. At the same time, there is still a lot that we don't know about our universe outside the solar system.
The challenge in finding earth-like planets is the sheer distances involved. It involves light years even between our sun and the nearest star. We can currently observe stars and other galaxies, but it is even more difficult to find a planet. The first challenge is that planets are often much smaller than the stars they orbit. The earth is one millionth the size of the sun. The second challenge is that planets don't emit or reflect much light. With these two conditions using ordinary astronomy tools to find planets is impossible

Many scientists speculate that our galaxy could be full of places like Pandora from the movie "Avatar" -- Earth-like worlds in solar systems besides our own.

That doesn't mean such worlds have been easy to find, however. Of the 400-plus planets so far discovered, none could support life as we know it on Earth.
"The problem with finding Earth-like planets," "is that their host stars can emit 10 million times more infrared light than the planet itself. And because planets like ours are small and orbit very close to their respective stars, it makes Earths almost impossible to see."

The rocky planet CoRoT-7 b was discovered circling a star some 480 light years from Earth. It is, however, a forbidding place and unlikely to harbor life. That's because it is so close to its star that temperatures might be above 4,000 degrees F (2,200 C) on the surface lit by its star and as low as minus 350 F (minus 210 C) on its dark side.

GJ 1214 b is an extrasolar super-Earth discovered in December 2009 orbiting the star GJ 1214, at a distance of 13 parsecs or approximately 40 light-years from earth, in the constellation Ophiuchus. It is the second exoplanet (after COROT-7b) discovered to have an established mass and radius less than those of the gas giants in the Solar System, and is the first of a new class of planets with small size and relatively low density. It is also the first super-Earth around which an atmosphere has been found. The planet is believed to be too hot to sustain Earth-type life, but could consist of 75 per cent water.
The planet is also significant because of its proximity to Earth, and because it transits a small parent star, which should allow its atmosphere to be studied using current technologies.

Fig. GJ 1214 b

Recently I was going through an article published in Scientific American (August issue) written by Dimitar D. Sasselov and Diana Valencia. Article is about the planets which could be similar to our earth. From last several years we are searching such planets in outer space which can support life. But we are still groping in darkness. Many claims have been made earlier but science needs evidence to accept such claims.

One such claim was in the year 2007, when some Swiss astronomers were studying a star close to the brightest star in the constellation of Libra, a red dwarf called Gliese 581, when they noticed that it was wobbling. They were intrigued by this as they understood that there must be something massive though invisible fairly near it exerting a gravitational pull on it. The result of this was the discovery of a large planet, which they called Gliese 581-B. It was obviously too close to its star, subject to too much radiation and just far too hot for it to support any form of life. Then in 2007 the same team of astronomers noticed a second wobble in the star’s movement, which implied the existence of a smaller planet further out. This was the cause of great excitement: the first earth-like planet outside the solar system had been discovered. It is twenty light-years away from the earth.

Imagine yourself grazing at the sky on a summer night. You look in the direction of a particular star that, you have heard, has a special planet orbiting around it. Although you cannot actually see the planet- you can barely see the star itself- you know it is several times larger than earth and, like earth, is made mostly of rock, quakes sometimes shake its surface, much of which is covered by oceans. Its atmosphere is not too different from the one we breathe, and its sky is swept by frequent storms and often darkened by the ash of volacanoes. But most of all, you know that scientists think it could harbor life – and that they plan to seek evidence for it.

This scenario could become reality within the next decades. Although most of the 450- odd extrasolar planets found so far are giants more similar to Jupiter, astronomers are beginning to discover some that may not be two different from earth. And NASA’s Kepler probe, a planet hunter sent aloft last year, will discover many more.

Of course, these worlds are light-years away, so even our most advanced instruments cannot actually see the details of their surfaces- the mountains, the clouds, the volcanoes- and perhaps never will. Usually all our telescopes can do is detect indirect signs of a planet’s presence and help us estimate its mass and how wide its orbit is. In some cases, they can also give information about a planet’s diameter and perhaps a few other details. In the case of the giant exoplanets, these details may include estimates about the atmosphere composition and wind dynamics.

That is a far cry from being able to measure anything specific about geology, chemistry or other features. Yet from those few numbers, researches can deduce surprisingly complex portraits of the far-off planets, using theoretical modeling, computer simulations and even laboratory experiments, combined with established knowledge of earth and other planets of the solar system.

Finding a planet that harbors life may have to wait until astronomers are better able to detect rocky planets that are farther from their stars. Spotting true Earth-sized planets is challenging with current technology, but the presence of super-Earths suggests finding a world like ours is just a matter of time, researchers say.