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Journey into uncharted voids of the Milky Way
Water shortages could increase tensions in the Middle East TRENDS
Debt and doubt loom large over Durban climate talks Amazon forest loss at lowest in 23 years Prof Yash
Pal THIS UNIVERSE |
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Journey into uncharted voids of the Milky Way AFTER a voyage lasting more than 34 years, a spacecraft that has travelled further than any man-made object is on the verge of leaving the Solar System and entering the mysterious region of interstellar space, where nothing terrestrial has gone before. Scientists at the US National Aeronautics and Space Administration (NASA) said the Voyager 1 space probe, which has travelled about 11 billion miles since its launch in 1977, has entered the cosmic equivalent of the doldrums, where the high-speed solar winds die down at the very edge of the Solar System. Voyager 1, launched within weeks of its twin probe, Voyager 2, was originally designed to explore Jupiter and Saturn. After making a string of important observations, such as active volcanoes on Jupiter’s moon Io and the intricacies of Saturn’s rings, the mission was extended. Voyager 2 went on to explore the faraway planets of Uranus and Neptune.
However, long after the official planetary missions ended, both spacecraft continued to plough through the farthest regions of the Solar System, while maintaining radio contact with mission control through its Deep Space Network. NASA expects that within the next few months – or possibly years if margins of error are taken into account – Voyager 1 will finally leave the Solar System for good and begin its journey through the vast void of interstellar space that comprises most of the Milky Way galaxy. Voyager 2 — travelling not far behind — will follow suit. Scientists at NASA said that over the past year, Voyager 1 had entered a kind of “cosmic purgatory” where the wind of electrically charged particles streaming from the Sun has calmed. Both spacecraft are now in a region known as the “heliosheath”, the outermost layer of the Solar System, where the solar wind, which can travel 16 miles per second, is being slowed down by the rising pressure of interstellar gas. NASA scientists believe this indicates the imminent entry of Voyager 1 into the interstellar region, which is dominated by another kind of magnetic wind coming from a different direction of deep space. “Voyager tells us now that we’re in a stagnation region in the outermost layer of the ‘bubble’ around our Solar System. Voyager is showing that what is outside is pushing back. We shouldn’t have long to wait to find out what the space between the stars is really like,” said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. NASA changed the orientation of Voyager 1 four times this year to see whether the solar wind and magnetic field lines had switched direction. Data released at the American Geophysical Union meeting in San Francisco shows the magnetic field lines have not changed, indicating that Voyager 1 is still just within the “heliosphere”, the magnetic bubble of charged particles created by the Sun. “We have seen the same east-west direction of the magnetic field since we launched. That’s the solar magnetic field. Once we leave the heliosphere we will enter the magnetic field of the galaxy and all the data to date suggest that this field is orientated more north-south,” Dr Stone told the meeting. — The Independent THE FINAL FRONTIER: BETWEEN THE STARS
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Water shortages could increase tensions in the Middle East SCIENTISTS studying ancient mud samples taken from the bed of the Dead Sea separating Israel and Jordan have warned that the fragile political situation in the Middle East will be made worse by the intense water shortages their study is predicting. Sediment cores drilled about 900ft down in the centre of the Dead Sea’s muddy basin — an environmental record stretching back 2,00,000 years — have shown that the giant lake has dried out in the past. This suggests that taking freshwater from rivers for irrigating crops could make a regional, prolonged drought almost inevitable. Researchers said their findings suggest that the entire water cycle in the region is being destabilised by the over-abstraction of water from rivers that drain into the Dead Sea and the Sea of Galilee, and that this could lead to conflict between Israel and its neighbours. “The Dead Sea is already drying up because humans are using so much water. The evidence it has actually gone away without any human intervention, under conditions that might return soon, is something people should think hard about,” said Steven Goldstein, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory in New York. “As of now, virtually no freshwater is entering the Dead Sea. All the water in the valleys is being used, and that’s part of the problem...(global warming) models predict that the water now flowing down the rivers that is being used won’t be going down the rivers any more,” Dr Goldstein said. Water is already an intensely political issue in the Middle East but the discovery that the Dead Sea dried out completely during the last interglacial period some 1,25,000 years ago suggests that the region is more vulnerable to catastrophic drought than many expert had previously believed. “Now that we have evidence from cores that the lake did actually dry down, all the previous climate models must be reconsidered (because) the lake might actually go dry much sooner... There are political implications of this big drying down because water is what causes wars,” Professor Emi Ito of the University of Minnesota said. — The Independent |
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Debt and doubt loom large over Durban climate talks DURBAN, South Africa: Economic crisis and the top three polluters China, the US and India, loomed as obstacles to a new global deal at the start of a second make-or-break week of UN climate talks in the South African city of Durban. After a first week of preliminary discussion, serious doubt hangs over the future of the Kyoto Protocol, whose first commitment period on tackling climate change expires at the end of next year. Amazon forest loss at lowest in 23 years BRASILIA: Deforestation in Brazil's Amazon region fell to its lowest in 23 years in the year through July, the government said, attributing the drop to its tougher stance against illegal logging. Destruction of the Brazilian portion of the world's largest rain forest dropped 11 per cent to 6,238 square km (2,400 square miles) over the 12-month period, satellite data from Brazil's National Institute for Space Research showed.
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THIS UNIVERSE A karate master doesn't feel pain if he successfully breaks a brick with his hand. On the contrary, his hand hurts more when he does not succeed. Please explain. Good question. When the karate master breaks the brick, his impact is greater than the strength of the brick. This means that his hand is decelerated to zero over a period of time longer than in the case he could not break the brick. Lesser the time within which his hand is stopped, and greater would be force on it, meaning a greater impact on the hand. That is the reason you get the result that his hand hurts more when he does not succeed! Why does an iron rod seem to be much colder than other objects at room temperature? The iron rod is most probably much colder than other objects at the room temperature. When you touch it with your bare hand on a winter morning, it does seem to be much colder than the other objects like the bed stand and bed covers. The reason for this is that a lot of calories are taken from your body to warm up the iron rod to your body temperature in a short period of time because of its high heat conductivity. Readers can e-mail their questions to Prof Yash Pal at palyash.pal@gmail.com |
