Interesting Stuff

The depletion of the ozone layer shielding Earth from damaging ultraviolet rays has reached an unprecedented low over the Arctic this spring because of harmful chemicals and a cold winter, the U.N. weather agency said Tuesday.

The Earth's fragile ozone layer in the Arctic region has suffered a loss of about 40 percent from the start of winter until late March, exceeding the previous seasonal loss of about 30 percent, the World Meteorological Organization said.

The Geneva-based agency blamed the loss on a buildup of ozone-eating chemicals once widely used as coolants and fire retardants in a variety of appliances and on very cold temperatures in the stratosphere, the second major layer of the Earth's atmosphere, just above the troposphere.

Arctic ozone conditions vary more than the seasonal ozone "hole" that forms high in the stratosphere near the South Pole each winter and spring, and the temperatures are always warmer than over Antarctica.

Because of changing weather and temperatures some Arctic winters experience almost no ozone loss while others with exceptionally cold stratospheric conditions can occasionally lead to substantial ozone depletion, U.N. scientists say.

This year the Arctic winter was warmer than average at ground level, but colder in the stratosphere than normal Arctic winters. U.N. officials say the latest losses — unprecedented, but not entirely unexpected — were detected in observations from the ground and from balloons and satellites over the Arctic.

Atmospheric scientists who are concerned about global warming focus on the Arctic because that is a region where the effects are expected to be felt first.

Ozone scientists have said that significant Arctic ozone depletion is possible in the case of a cold and stable Arctic stratospheric winter. Ozone losses occur over the polar regions when temperatures drop below -78 degrees Celsius (-108 Fahrenheit), when clouds form in the stratosphere.

Average temperatures in January range from about -40 to 0 C (-40 to 32 F), while average temperatures in July range from about -10 to 10 C (14 to 50 F).

"The Arctic stratosphere continues to be vulnerable to ozone destruction caused by ozone-depleting substances linked to human activities," said WMO secretary-general Michel Jarraud. "The degree of ozone loss experienced in any particular winter depends on the meteorological conditions."

The loss comes despite the U.N. ozone treaty, known as the 1987 Montreal Protocol, which has resulted in cutbacks in ozone-damaging chemicals, such as chlorofluorocarbons, halons and other, that were used in the making of refrigerators, air conditioners, fire extinguishers and even hairspray.

The 196-nation ozone treaty encourages industries to use replacement chemicals less damaging to ozone, the atmospheric layer that helps protect against the sun's most harmful rays.

But because these compounds have long atmospheric lifetimes, it takes decades for their concentrations to subside to pre-1980 levels as was agreed in the Montreal Protocol.

U.N. officials project the ozone layer outside the polar regions will recover to pre-1980 levels sometime between 2030 and 2040.

Source: Yahoo News

God did not create the universe and the "Big Bang" was an inevitable consequence of the laws of physics, the eminent British theoretical physicist Stephen Hawking argues in a new book.

In "The Grand Design", co-authored with U.S. physicist Leonard Mlodinow, Hawking says a new series of theories made a creator of the universe redundant, according to the Times newspaper which published extracts on Thursday.

"Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist," Hawking writes.

"It is not necessary to invoke God to light the blue touch paper and set the universe going."

Hawking, 68, who won global recognition with his 1988 book "A Brief History of Time", an account of the origins of the universe, is renowned for his work on black holes, cosmology and quantum gravity.

Since 1974, the scientist has worked on marrying the two cornerstones of modern physics -- Albert Einstein's General Theory of Relativity, which concerns gravity and large-scale phenomena, and quantum theory, which covers subatomic particles.

His latest comments suggest he has broken away from previous views he has expressed on religion. Previously, he wrote that the laws of physics meant it was simply not necessary to believe that God had intervened in the Big Bang.

He wrote in A Brief History ... "If we discover a complete theory, it would be the ultimate triumph of human reason -- for then we should know the mind of God."

In his latest book, he said the 1992 discovery of a planet orbiting another star other than the Sun helped deconstruct the view of the father of physics Isaac Newton that the universe could not have arisen out of chaos but was created by God.

"That makes the coincidences of our planetary conditions -- the single Sun, the lucky combination of Earth-Sun distance and solar mass, far less remarkable, and far less compelling evidence that the Earth was carefully designed just to please us human beings," he writes.

Hawking, who is only able to speak through a computer-generated voice synthesiser, has a neuro muscular dystrophy that has progressed over the years and left him almost completely paralysed.

He began suffering the disease in his early 20s but went on to establish himself as one of the world's leading scientific authorities, and has also made guest appearances in "Star Trek" and the cartoons "Futurama" and "The Simpsons".

Last year he announced he was stepping down as Cambridge University's Lucasian Professor of Mathematics, a position once held by Newton and one he had held since 1979.

"The Grand Design" is due to go on sale next week.