On Feb. 2, 2007, the United Nations scientific panel studying

climate change declared that the evidence of a warming trend is

“unequivocal”, and that human activity has “very likely” been the driven 【M1】________

force in that change over the last 50 years. The last report by the group,

the Intergovernmental Panel on Climate Change, in 2001, had found

that humanity had “likely” played a role.

The addition of that single word “very” did more than reflect to 【M2】________

mounting scientific evidence that the release of carbon dioxide and other

heat-trapping gases from smokestacks, tailpipes and burning forests have 【M3】________

played a central role in raising the average surface temperature of earth 【M4】________

by more than 1 degree Fahrenheit in 1900. It also added new momentum 【M5】_________

to a debate that now seems centered less on that humans are warming the 【M6】_________

planet, but instead on what to do about it. In recent months, business

groups have banded together to make unprecedented calls to federal 【M7】_________

regulation of greenhouse gases. The subject had a red-carpet moment

when former Vice President Al Gore’s documentary, “An Inconvenient

Truth”, was rewarded an Oscar; and the Supreme Court made its first 【M8】_________

global warming-related decision, ruling 5 to 4 that the Environmental

Protection Agency had not justified their position that it was not 【M9】_________

authorized to regulate carbon dioxide.

The latest report from the climate panel predicted that the global

temperature is likely to rise between 3. 5 and 8 degrees Fahrenheit

whether the carbon dioxide concentration in the atmosphere reaches 【M10】________

twice the level of 1750. By 2100, sea levels are likely to rise between 7

and 23 inches, it said, and the changes now underway will continue for

centuries to come.

A summary of the physical and chemical nature of life must begin,

not on the Earth, but in the Sun; in fact, at the Sun’s very center. It is

here where is to be found the source of the energy that the Sun 【M1】_________

constantly pours out into the space as light and heat. This energy is 【M2】_________

liberated at the center of the Sun as billions on billions of nuclei of 【M3】_________

hydrogen atoms collide with each other and fuse together to form nuclei

of helium, and, in doing so, releases some of the energy that is stored in 【M4】_________

the nuclei of atoms. The output of light and heat of the Sun requires that

some 600 million tons of hydrogen are converted into helium in the Sun 【M5】_________

every second. This the Sun has been done for several thousands of 【M6】_________

millions of years.

The nuclear energy is released at the Sun’s center as high-energy

gamma radiation, a form of electromagnetic radiation like light and

radio waves, only of very much short wavelength. This gamma radiation 【M7】_________

is absorbed by atoms inside the Sun, to be reemitted at slight longer 【M8】_________

wavelengths. This radiation, in its turn, is absorbed and remitted. As

the energy filters through the layers of the solar interior, it passes

through the X-ray part of the spectrum, eventually becoming light. At

this stage, it has reached that we call the solar surface, and can escape 【M9】_________

into space, without being absorbed further by solar atoms. A very small

fraction of the Sun’s light and heat emitted in such directions that, after 【M10】________

passing unhindered through interplanetary space, it hits the Earth.

In the house where I grew up, it was our custom to leave the front

door on the latch at night. No one carried keys.

Today doors do not stay unlocked, thus for part of an evening. The 【M1】_________

era of leaving the front door open has gone forever. It has been replaced

of by locks, security chains, electronic alarm systems and tripwires 【M2】_________

hooked up to a police station or private guard firm. Many suburban

families even have sliding glass doors on their patios, with steel bars

elegantly building in so no one can pry the doors open. 【M3】_________

A recent public-service advertisement by an insurance company

featured not actuarial charts or a picture of a child’s bicycle with a 【M4】_________

padlock attached to it.

It is the insurance companies which pay for stolen goods, but who is 【M5】_________

going to pay for that the new atmosphere of distrust and fear is doing to 【M6】_________

our way of life? Who is going to make the psychological payment for the 【M7】_________

transformation of America from the Land of the Free to the Land of the

Lock?

For some reason we are satisfied when we think we are well-

protected; it does not occur us to ask ourselves: Why are we having to 【M8】_________

barricade ourselves for our neighbors and fellow citizens, and when, 【M9】_________

exactly, did this start to take over our lives?

Even a decade ago, most private businesses had a policy of free

access. Thus, today you have to carry some kind of access card to enter 【M10】________

your place of work. Maybe the security guard at the front desk knows

your face and will wave you in most days, but the fact remains that the

business you work for feels threatened enough to keep outsiders away via

these “keys”.