China’s “spacewalker” heads backs to earth on sunday

Posted on September 28, 2008 by Rashid Faridi
Astronaut Zhai Zhigang of China holds the national flag after exiting the Shenzhou VII space craft in this September 27, 2008 video grab. Zhai became the first Chinese man to walk in space on Saturday, clambering out of the space craft in a technological feat that Beijing wants the world to marvel about.

Astronaut Zhai Zhigang of China holds the national flag after exiting the Shenzhou VII space craft in this September 27, 2008 video grab. Zhai became the first Chinese man to walk in space on Saturday, clambering out of the space craft in a technological feat that Beijing wants the world to marvel about.

The man who made China’s historic first “footprint in space” is preparing to return to earth on Sunday after a historic mission that boosted national pride and took his country one step closer to the moon.

Zhai Zhigang and two other astronauts on the Shenzhou VII craft are due to land around 5 p.m. (5 a.m. EDT) in northern Inner Mongolia region.

His successful space walk in a $4.4 million, domestically designed, suit caps an eventful year for China in which it has both coped with the tragedy of the devastating Sichuan earthquake and reveled in the Beijing Olympics.

The achievement was hailed by Communist Party leaders as a success for the whole nation and during his twenty minutes outside the craft — but tethered to it to prevent him floating off — the son of a snack-seller unveiled a small Chinese flag.

It was China’s third manned space mission. The ability to “space walk” is key to a longer-term goal of assembling a space lab and then a larger space station, and maybe one distant day making a landing on the moon.

The fast-growing Asian power wants to be sure of a say in the future use of space and its resources, and its space programme has come a long way since late leader Mao Zedong lamented that China could not even launch a potato into space.

Its first manned spaceflight was in 2003, followed by a two-man flight in 2005. The only other countries that have sent people into space are Russia and the United States.

But Xinhua also said that China remained far behind the two leading space powers, Russia and the United States.

It will start selecting new trainee astronauts for an even more demanding mission, orbiter docking, once the Shenzhou VII crew are safely back to earth, Xinhua said.
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Life greener in cities than in the countryside?

Posted on September 27, 2008 by Rashid Faridi

Singapore-Clean and Green

Singapore-Clean and Green

City-dwelling, bike-riding recyclers are finally getting the recognition they deserve for their environmentally friendly lifestyles.

A researcher at the London-based International Institute for Environment and Development argues in a journal article published on Friday that many city residents actually pollute less than families in rural areas.

“People who live in the suburbs or commute actually have much higher greenhouse gas emissions per person than people living in (the London district of) Chelsea for the same income level,” David Satterthwaite told Reuters.

That’s because country-dwellers tend to have larger homes that need to be heated or cooled and higher car use per household.

The study in the journal Environment and Urbanization says cities are often blamed for producing most of the world’s greenhouse gas emissions but actually generate just two-fifths or less.

Satterthwaite argues that cities in wealthy nations can set an example for low carbon living by providing good public transport and energy-efficient buildings. He singles out Barcelona – which has a third of Spain’s average emissions per person – and other historic compact cities like Amsterdam which are easy to walk around.

Culture is also an ally in the fight against climate change. “There’s so much in London or Paris that isn’t high greenhouse gas-emitting: the culture, the art, the buildings, the theatre, the music, the museums, the libraries,” Satterthwaite said.

But while cities are often unfairly blamed for producing 75 to 80 percent of the world’s greenhous gas emissions, their responsibility creeps back up when you look at it from a consumption perspective.

Satterthwaite believes it would be fairer to allocate greenhouse gas emissions according to the location of the people who consume the goods and services responsible for the emissions rather than to the place they are produced.

So if you live in Berlin and buy a Chinese-made T-shirt or digital camera, the emissions caused by the manufacturing process would go into your city’s pot, not Guangzhou’s.

On this measure, Satterthwaite estimates city emissions would account for between 60 and 70 percent of the global total. Breaking that down, richer cities would be the clear culprits.

Some parts of poor cities – like the inner-city settlement of Dharavi in Mumbai where 600,000 people live and work crammed into an area around 2 km square – might even have a negative tally, especially if they’re home to poor people who survive by reclaiming and recycling waste.

“Allocating emissions to consumers rather than producers shows that the problem is not cities but a minority of the world’s population with high-consumption lifestyles,” Satterthwaite said.

“But I can see the huge – or probably impossible – political difficulties of getting that accepted, if suddenly the responsibility of the rich world goes up even further,” he admitted.

What do you think? How could your city cut its carbon emissions? Should we measure emissions from the perspective of production or consumption?

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Greenhouse Effect

Posted on September 26, 2008 by Rashid Faridi

Some of the energy from the sun is trapped inside our atmosphere as it is reflected back from the earth towards space. This natural process is called the greenhouse effect, as the atmosphere acts like the glass walls of a greenhouse, which allows the sun’s rays to enter but keeps the heat in.

The gases which make this happen (“greenhouse gases”) are mainly water vapour and carbon dioxide. As humans emit more carbon dioxide and other greenhouse gases into the atmosphere the greenhouse effect becomes stronger. This causes the earth’s climate to change unnaturally.

The “greenhouse effect” often gets a bad rap because of its association with global warming, but the truth is we couldn’t live without it.

What Causes the Greenhouse Effect?
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet’s surface and is reflected upward again as a type of slow-moving energy called infrared radiation.

As it rises, infrared radiation is absorbed by “greenhouse gases” such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.

Although greenhouse gases make up only about 1 percent of the Earth’s atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet.

This phenomenon is what scientists call the “greenhouse effect.” Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem.

How Do Humans Contribute to the Greenhouse Effect?
While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.

The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.

Burning natural gas, coal and oil —including gasoline for automobile engines—raises the level of carbon dioxide in the atmosphere.

Some farming practices and land-use changes increase the levels of methane and nitrous oxide.

Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and “global warming” that is currently under way.

Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.

Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.

Ultimately, more greenhouse gases means more infrared radiation trapped and held, which gradually increases the temperature of the Earth’s surface and the air in the lower atmosphere.

The Average Global Temperature is Increasing Quickly
Today, the increase in the Earth’s temperature is increasing with unprecedented speed. To understand just how quickly global warming is accelerating, consider this:

During the entire 20th century, the average global temperature increased by about 0.6 degrees Celsius (slightly more than 1 degree Fahrenheit).

Using computer climate models, scientists estimate that by the year 2100 the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (approximately 2.5 degrees to 10.5 degrees Fahrenheit).

Not All Scientists Agree
While the majority of mainstream scientists agree that global warming is a serious problem that is growing steadily worse, there are some who disagree. John Christy, a professor and director of the Earth System Science Center at the University of Alabama in Huntsville is a respected climatologist who argues that global warming isn’t worth worrying about.

Christy reached that opinion after analyzing millions of measurements from weather satellites in an effort to find a global temperature trend. He found no sign of global warming in the satellite data, and now believes that predictions of global warming by as much as 10 degrees Fahrenheit by the end of the 21st century are incorrect.
links:http://www.defra.gov.uk

http://environment.about.com

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Mysterious New ‘Dark Flow’ Discovered in Space

Posted on September 25, 2008 by Rashid Faridi

The recently discovered galaxy Segue 1 orbits the Milky Way, and is believed to be composed of mainly dark matter

The recently discovered galaxy 'Segue 1' orbits the Milky Way, and is believed to be composed of mainly dark matter

As if the mysteries of dark matter and dark energy weren’t vexing enough, another baffling cosmic puzzle has been discovered.

Patches of matter in the universe seem to be moving at very high speeds and in a uniform direction that can’t be explained by any of the known gravitational forces in the observable universe. Astronomers are calling the phenomenon “dark flow.”

The stuff that’s pulling this matter must be outside the observable universe, researchers conclude.

When scientists talk about the observable universe, they don’t just mean as far out as the eye, or even the most powerful telescope, can see. In fact there’s a fundamental limit to how much of the universe we could ever observe, no matter how advanced our visual instruments. The universe is thought to have formed about 13.7 billion years ago. So even if light started travelling toward us immediately after the Big Bang, the farthest it could ever get is 13.7 billion light-years in distance. There may be parts of the universe that are farther away (we can’t know how big the whole universe is), but we can’t see farther than light could travel over the entire age of the universe.

Mysterious motions

Scientists discovered the flow by studying some of the largest structures in the cosmos: giant clusters of galaxies. These clusters are conglomerations of about a thousand galaxies, as well as very hot gas which emits X-rays. By observing the interaction of the X-rays with the cosmic microwave background (CMB), which is leftover radiation from the Big Bang, scientists can study the movement of clusters.

The X-rays scatter photons in the CMB, shifting its temperature in an effect known as the kinematic Sunyaev-Zel’dovich (SZ) effect. This effect had not been observed as a result of galaxy clusters before, but a team of researchers led by Alexander Kashlinsky, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md., found it when they studied a huge catalogue of 700 clusters, reaching out up to 6 billion light-years, or half the universe away. They compared this catalogue to the map of the CMB taken by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) satellite.

They discovered that the clusters were moving nearly 2 million mph (3.2 million kph) toward a region in the sky between the constellations of Centaurus and Vela. This motion is different from the outward expansion of the universe (which is accelerated by the force called dark energy).

“We found a very significant velocity, and furthermore, this velocity does not decrease with distance, as far as we can measure,” Kashlinsky told SPACE.com. “The matter in the observable universe just cannot produce the flow we measure.”

Inflationary bubble

The scientists deduced that whatever is driving the movements of the clusters must lie beyond the known universe.

A theory called inflation posits that the universe we see is just a small bubble of space-time that got rapidly expanded after the Big Bang. There could be other parts of the cosmos beyond this bubble that we cannot see.

In these regions, space-time might be very different, and likely doesn’t contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.

“The structures responsible for this motion have been pushed so far away by inflation, I would guesstimate they may be hundreds of billions of light years away, that we cannot see even with the deepest telescopes because the light emitted there could not have reached us in the age of the universe,” Kashlinsky said in a telephone interview. “Most likely to create such a coherent flow they would have to be some very strange structures, maybe some warped space time. But this is just pure speculation.”

Surprising find

Though inflation theory forecasts many odd facets of the distant universe, not many scientists predicted the dark flow.

“It was greatly surprising to us and I suspect to everyone else,” Kashlinsky said. “For some particular models of inflation you would expect these kinds of structures, and there were some suggestions in the literature that were not taken seriously I think until now.”

The discovery could help scientists probe what happened to the universe before inflation, and what’s going on in those inaccessible realms we cannot see.
link/s:http://www.space.com

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