|
|
|
|
| SCIENCE & TECHNOLOGY |
|
|
|
Massive Greenland ice melt freezes observers Canada unveils device for big space telescope Stripping air of CO2 may become unavoidable Prof Yash
Pal THIS UNIVERSE |
|
|
Massive Greenland ice melt freezes observers THE vast ice sheet of Greenland, which holds enough water to raise global sea levels by 7.2 metres, underwent a remarkable transformation for a few days this month when scientists observed an unprecedented melting of its frozen surface. For the first time since satellites began recording changes to Greenland from space more than 30 years ago, scientists observed surface melting across almost the entire ice sheet — the second-largest body of ice after Antarctica. The phenomenon in Greenland was so unusual and unexpected that researchers at Nasa’s Jet Propulsion Laboratory in Pasadena, California, initially could not believe what they were seeing and so quickly sought verification from colleagues elsewhere. “This was so extraordinary that at first, I questioned the result: was this real or was it due to a data error?” said Son Nghiem, whose job at the laboratory is to analyse satellite radar data. At this time of the year, about half of the surface of the ice sheet usually experiences some kind of surface melting as summer daytime temperatures rise above freezing point. However, scientists at the US National Aeronautics and Space Administration (NASA) were amazed to discover that on July 11 and 12, surface melting had extended across 97 per cent of the ice sheet — the most widespread melting they have witnessed. The observation comes weeks after an iceberg twice the size of Manhattan broke away from the Petermann glacier in northern Greenland and other scientists recorded a rapid loss of floating sea ice in the Arctic basin. Dorothy Hall at Nasa’s Goddard Space Flight Centre in Greenbelt, Maryland soon supplied the verification in the form of temperature data from two other Nasa satellites. She confirmed unusually high temperatures over the entire ice sheet, which at 1.7 million square kilometres is three times the size of Texas, or more than 16 times the size of England. Thomas Mote, a climatologist at the University of Georgia, then came up with a meteorological explanation for the highly unusual observation. A ridge of warm air, called a heat dome, has formed over Greenland. Dr Mote said that it was in fact the latest of a series of ridges that had dominated Greenland’s weather since the end of May. “Each successive ridge has been stronger than the previous one,” he said. The Greenland ice sheet is 1,500 miles long, 700 miles wide, and up to two miles thick at its highest point. The current ice sheet is believed to be 1,10,000 years old, but there may have been ice sheets on Greenland for 18 million years or more. —
The Independent
|
|||
|
Canada unveils device for big space telescope THE Canadian Space Agency has unveiled a precision equipment that will be used on the James Webb Space Telescope, the successor to the Hubble. The Webb, billed as a powerful time machine capable of uncovering the origins of the universe, is scheduled for launch in 2018. Canada’s contribution to the biggest space telescope ever made is a two-in-one instrument, reported Xinhua. The first part is a Fine Guidance System, which consists of two identical cameras (just in case one fails), dubbed “Canada eyes” by the University of Montreal. It will enable the telescope to point at a celestial object within one millionth of a degree of accuracy, likened to measuring the width of a hair from five km away. The second, a spectrometer called the Near-Infrared Imager and Slitless Spectrograph, will search for galaxies formed after the Big Bang that created the universe some 13.7 billion years ago. It will also look for signs of life through the presence of oxygen, carbon dioxide and methane in planetary atmospheres around distant stars, and try to find new stars forming. Retired astronaut Steve MacLean, head of the Canadian Space Agency, lauded the Canadian-made technology for its capability of “unprecedented levels of precision to conduct breakthrough science on board the largest, most complex and most powerful telescope ever built”. The instruments — about the size of a kitchen stove — will be delivered to the National Aeronautics and Space Administration (NASA) for integration into the Webb telescope July 30. Named after the second NASA administrator who crafted the Apollo programme in the 1960s, the Webb will replace the Hubble Space Telescope, which was sent into orbit 22 years ago. Unlike the Hubble, positioned 568 km, above the Earth, the Webb will be placed 9,40,000 miles, or 1.5 million km from Earth (four times the distance between the Moon and the Earth). At that distance, the Webb telescope will be “too far from Earth to be serviced by astronauts like Hubble was”, noted MacLean. “The technology simply has to work.” To observe objects billions of light years away, the Webb, equipped with a primary mirror about seven times larger than Hubble’s and a tennis court-sized sunshield, will be large enough to gather very faint light to help scientists look back to a time when galaxies were forming, and cold enough to detect infrared light, or heat, emitted from distant objects while operating in a temperature of -230 degrees Celsius for five to 10 years. By contrast, the Hubble telescope was designed to operate at 21 degrees Celsius and look at ultraviolet and visible light. About 100 times as powerful as the Hubble, the Webb will essentially take photographs of “the first stars lighting up at the beginning of the universe”, said David Lizius, president of Ottawa-based Com Dev Ltd. which built the instrumentation.
— IANS
|
|||
|
Stripping air of CO2 may become unavoidable EMERGING techniques to strip the atmosphere of carbon dioxide (CO2) and store it away to stabilise climate may become unavoidable, as our planet tips into a state of potentially dangerous warming. Researchers from Columbia University’s Earth Institute argue that upfront costs of directly taking carbon out of the air will be expensive, but such technology may become more affordable as it develops and is more widely used. The techniques would address sources of CO2 that other types of carbon capture and storage cannot, and have the potential to even lower the amount of CO2 in the air — significant because the world may already have crossed beyond the point where the climate can be stabilised by just limiting emissions, the journal Proceedings of the National Academy of Sciences reports. “The field of carbon sequestration, the field of capture and storage as a community is too timid when it comes to new ideas,” said Klaus Lackner, director of the Lenfest Center for Sustainable Energy at Columbia, who led the study. “You cannot rule out new technology simply because the current implementation is too expensive,” he said.
— IANS
|
|||
|
I have read somewhere that at 10 per cent of the speed of light an object’s mass is only 0.5 per cent, which is more than normal, while at 90 per cent of the speed of light it would be more than twice its normal mass. As an object approaches the speed of light, its mass rises rapidly. It can, in fact, never reach the speed of light, because by then its mass would have become infinite. If true, where does this extra mass come from? We know that mass cannot be created and cannot be destroyed; it can only change its form. What you have stated is completely true. This comes out by putting numbers in the formula for the Lorentz transformation applicable in case of Special Relativity. You have to remember that the proper mass or rest mass is not changing but what changes is the dynamic mass. You will get the changing momentum of the particle when you multiply it with velocity. There is no inconsistency problem with observation. If particle at rest decays into two particles it will still decay into those two particles while moving at any velocity. Can we create an infinite source of energy? You are skeptical and I would with you. But if we have to borrow an almost infinite amount and give firm promise to return it, this possibility could be explored if the period of loan is short enough, say 10 to the power minus 33 seconds or less! Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com |
|||
|
New Russian space
station docking gear test fails MOSCOW:
A test of new spacecraft docking gear for Russian flights to the
International Space Station failed, the US and Russian space agencies
said, casting doubt on the automated system meant to simplify missions
to the orbiting outpost. The space agencies said a new docking attempt
would likely take place on Sunday, after an unmanned Japanese
spacecraft, the HTV-3, reaches the station and is manually berthed by
astronauts later this week. Ion
Torrent vies for $10-million genome prize NEW
YORK: A genome-sequencing contest announced six years ago finally
has its first entrant: Life Technologies Corp’s Ion Torrent, which
said it was entering the fray. The Archon Genomics X Prize will award
$10 million to the first team that sequences the complete genomes of
100 people aged 100 or older in 30 days or less, for no more than
$1,000 each, and with an error rate of no more than 0.0001 per cent. Bacteria
outbreak in Northern Europe due to ocean warming LONDON:
Manmade climate change is the main driver behind the unexpected
emergence of a group of bacteria in northern Europe which can cause
gastroenteritis, new research by a group of international experts
shows. The paper, published in the journal Nature Climate Change,
provided some of the first firm evidence that the warming patterns of
the Baltic Sea have coincided with the emergence of Vibrio infections
in northern Europe. — Reuters
|
Surface melting extended across 97 per cent of country’s ice sheet this month
