Exotic Super-Earth:Densest Known Rocky Planet
Posted: April 29, 2011 Filed under: inventions, Solar System, Space Leave a comment »
An international team of astronomers have revealed details of a “super-exotic” exoplanet that would make the planet Pandora in the movie Avatar pale in comparison.The planet, named 55 Cancri e, is 60 percent larger in diameter than Earth but eight times as massive. Twice as dense as Earth — almost as dense as lead — it is the densest solid planet known, according to a team led by astronomers from the Massachusetts Institute of Technology (MIT), the University of British Columbia (UBC), the Harvard‑Smithsonian Center for Astrophysics and the University of California at Santa Cruz (UCSC).
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Tracking Tornadoes in Real Time
Posted: April 29, 2011 Filed under: Natural Calamities Leave a comment »Wednesday’s tornadic supercell storms that killed upwards of 280 people in a wind-driven rampage across the Midwestern United States is the first of its caliber to have been forecasted and monitored through its progression with such first-hand accounts and eyes-in-the-sky intensity.
Reed Timmer and the team of Discovery Channel Storm Chasers monitored the developing storms, filming at least four tornadoes in the process. Their priority for that day – as was the case for veteran storm watchers across the region – was to keep local authorities apprised of the path of destruction these twisters were taking in an effort to save lives.
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Ecosystem Collapse can be Predicted
Posted: April 29, 2011 Filed under: BIODIVERSITY, Ecosystem Leave a comment »
Researchers monitoring complex signals emanating from a remote Wisconsin lake have detected what they say is an unmistakable warning — a death knell — of the impending collapse of the lake’s aquatic ecosystem. Researchers have found that models used to assess catastrophic changes in economic and medical systems can also predict environmental collapse. Stock market crashes, epileptic seizures, and ecological breakdowns are all preceded by a measurable increase in variance—be it fluctuations in brain waves, the Dow Jones index, or, in the case of the Wisconsin lake, chlorophyll. The finding, reported April 29 in the journal Science by a team of researchers led by Stephen Carpenter, a limnologist at the University of Wisconsin-Madison, is the first experimental evidence that radical change in an ecosystem can be detected in advance, possibly in time to prevent ecological disaster.
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Urban Sprawl is Finished:Rising Oil Prices Will Turn Suburbs into Remote Slums
Posted: April 27, 2011 Filed under: opinions, Urban Studies Comments Off
Many predict oil prices to start rising in just a few years. Even the US military says that we could start seeing massive shortages of oil as soon as 2015. Such shortages would not only effect the products we buy and the kind of transportation we use — but could reshape the way we organize our societies from the ground up.
Highlighting this often overlooked factor, a new study from the Australian Planner goes so far to argue that unless it radically reforms its urban planning and transportation policy, suburbs will become slums. There have been plenty of stories done on the topic of suburbs-turning-slums in the wake of the housing crash, but this report suggests that the price of oil will make the shift permanent.
Professor Peter Newman of Curtin University, who is also an adviser to the federal government, said the most compelling finding of the research was that ‘urban sprawl is finished’. He said: ‘If we continue to roll out new land releases and suburbs that are car-dependent, they will become the slums of the future.’”
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River Stages:Middle Course of the River – Meanders & Ox-bow Lakes
Posted: April 27, 2011 Filed under: Landforms, Rivers, water 1 Comment »In this stage the river channel has become much wider and deeper as the channel has been eroded and the river has been fed by many tributaries upstream. Consequently, despite the more gentle gradient the velocity of flow may be as fast as in the uplands. As well as changes in the river channel, its surrounding valley has also become wider and flatter in cross-section with a more extensive floodplain. One of the most distinctive features of the river in the middle course is its increased sinuousity. Unlike the relatively straight channel of the upper course, in the middle course there are many meanders (bends) in the river.
Meander Formation
A meander in general is a bend in a sinuous watercourse. A meander is formed when the moving water in a stream erodes the outer banks and widens its valley. A stream of any volume may assume a meandering course, alternatively eroding sediments from the outside of a bend and depositing them on the inside. The result is a snaking pattern as the stream meanders back and forth across its down-valley axis. When a meander gets cut off from the main stream, an oxbow lake is formed. Over time meanders migrate downstream, sometimes in such a short time as to create civil engineering problems for local municipalities attempting to maintain stable roads and bridges.
Meanders form due to the greater volume of water carried by the river in lowland areas which results in lateral (sideways) erosion being more dominant than vertical erosion, causing the channel to cut into its banks forming meanders.
1. Water flows fastest on the outer bend of the river where the channel is deeper and there is less friction. This is due to water being flung towards the outer bend as it flows around the meander, this causes greater erosion which deepens the channel, in turn the reduction in friction and increase in energy results in greater erosion. This lateral erosion results in undercutting of the river bankand the formation of a steep sided river cliff.
2. In contrast, on the inner bend water is slow flowing, due to it being a low energy zone, deposition occurs resulting in a shallower channel. This increased friction further reduces the velocity (thus further reducing energy), encouraging further deposition. Over time a small beach of material builds up on the inner bend; this is called a slip-off slope.
Ox-Bow Lake formation
An oxbow lake is a U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake. This landform is called an oxbow lake for the distinctive curved shape, named after part of a yoke for oxen. In Australia, an oxbow lake is called a billabong, derived from an indigenous language. The word “oxbow” can also refer to a U-shaped bend in a river or stream, whether or not it is cut off from the main stream.
An oxbow lake is formed when a river creates a meander, due to the river’s eroding the banks through hydraulic action and abrasion/corrosion. After a long period of time, the meander becomes very curved, and eventually the neck of the meander will touch the opposite side and the river will cut through the neck, cutting off the meander to form the oxbow lake.
Here is a Diagrammetic Representation of Ox-Bow Lake Formation:
- As the outer banks of a meander continue to be eroded through processes such
as hydraulic action the neck of the meander becomes narrow and
narrower. - Eventually due to the narrowing of the neck, the two outer bends
meet and the river cuts through the neck of the meander. The water now
takes its shortest route rather than flowing around the bend. - Deposition gradually seals off the old meander bend forming a
new straighter river channel. - Due to deposition the old meander bend is left isolated from the main
channel as an ox-bow lake. - Over time this feature may fill up with sediment and may gradually dry up
(except for periods of heavy rain). When the water dries up, the feature
left behind is knwon as a meander scar.
Links and Sources:
GCSE , Wikipedia(Meander), Wikipedia(Ox-Bow Lake)
Gravitational Tug of War Warps Spiral Shape of Galaxy
Posted: April 25, 2011 Filed under: Space Leave a comment »
The galaxies pairing in a new image, captured by the MPG/ESO 2.2-meter telescope in Chile, display some curious features, demonstrating that each member of the duo is close enough to feel the distorting gravitational influence of the other. The gravitational tug of war has warped the spiral shape of one galaxy, NGC 3169, and fragmented the dust lanes in its companion NGC 3166. Meanwhile, a third galaxy, NGC 3165, has a front-row seat to the gravitational twisting and pulling.
This galactic grouping, found about 70 million light-years away in the constellation Sextans (The Sextant), was discovered by the English astronomer William Herschel in 1783. Modern astronomers have gauged the distance between NGC 3169 (left) and NGC 3166 (right) as a mere 50 000 light-years, a separation that is only about half the diameter of the Milky Way galaxy. In such tight quarters, gravity can start to play havoc with galactic structure.
read here :http://www.sciencedaily.com/releases/2011/04/110420112330.htm
Melting Ice on Arctic Islands a Major Player in Sea Level Rise
Posted: April 24, 2011 Filed under: climate change, Glaciers Leave a comment »
Melting glaciers and ice caps on Canadian Arctic islands play a much greater role in sea level rise than scientists previously thought, according to a new study led by a University of Michigan researcher.
The United Nations projects that the oceans will rise by a full meter by the end of century. This could have ramifications for tens of millions of people who live in coastal cities and low-lying areas across the globe. Future tsunamis and storm surges, for example, would more easily overtop ocean barriers.
Links and Sources: http://www.sciencedaily.com/releases/2011/04/110420143608.htm
Big Changes in Atmosphere of Mars
Posted: April 24, 2011 Filed under: Space Leave a comment »
NASA’s Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet’s axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms.
Researchers using the orbiter’s ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet’s south pole. The scientists suspect that much of this carbon dioxide enters the planet’s atmosphere and swells the atmosphere’s mass when Mars’ tilt increases. The findings are published in the journal Science.
The newly found deposit has a volume similar to Lake Superior’s nearly 3,000 cubic miles (about 12,000 cubic kilometers). The deposit holds up to 80 percent as much carbon dioxide as today’s Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars’ atmosphere is about 95 percent carbon dioxide, in contrast to Earth’s much thicker atmosphere, which is less than .04 percent carbon dioxide.
Source: http://www.sciencedaily.com/releases/2011/04/110421190450.htm
Is Pluto a Comet with a Poisonous Atmosphere?
Posted: April 22, 2011 Filed under: opinions, Space Leave a comment »Pluto may no longer have official planetary status, but the dwarf planet does have an atmosphere. In fact, it’s the onlydwarf planet with a known atmosphere. What’s more, it has just been announced that its atmosphere reaches nearly one quarter of the way to Pluto’s largest moon Charon and swept back — like a cometary tail — by the weak pressure of the solar wind.
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Biological Arms Races in Birds
Posted: April 19, 2011 Filed under: BIODIVERSITY 1 Comment »
New research reveals how biological arms races between cuckoos and host birds can escalate into a competition between the host evolving new, unique egg patterns (or ‘signatures’) and the parasite new forgeries. Brood parasitic birds such as cuckoos lay eggs that mimic those of their hosts in an effort to trick them into accepting the alien egg and raising the cuckoo chick as one of their own. New research from the University of Cambridge has found that different bird species parasitised by the African cuckoo finch have evolved different advanced strategies to fight back.
One strategy is for every host female to lay a different type of egg, with egg colour and pattern varying greatly among nests. These egg ‘signatures’ make it harder for the cuckoo finch to lay accurate forgeries. Since the female cuckoo finch always lays the same type of egg throughout her lifetime, she cannot change the look of her egg to match those of different host individuals — thus her chances of laying a matching egg are exasperatingly small …
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