A Neighborhood of Planets
The nine planets, the Sun and
numerous other celestial bodies that make up our Solar
System are the inhabitants of a neighborhood that
has long amazed human beings - and its delicate balance
is what allowed life to flourish on Earth.
A planet is an object that orbits
a star and is larger than an asteroid. So far, human
civilization has not come across any other set of
planets like the Solar System, but outer space is
On Earth, the arrival of cyber-space
opened a new door to the knowledge held by people
about the celestial neighborhood in which they live.
Not only is there abundant information available on
the Internet, but one can explore the Solar System
and get an idea of its enormity with just a
click of the computer mouse.
One important portal is The
Nine Planets site, which provides a vast array
of information and links for cybernauts to navigate.
Just who are the inhabitants
of this celestial neighborhood? Centered around the
Sun are nine planets, approximately 80 moons and artificial
satellites that orbit the planets, plus millions of
asteroids and comets.
Welcome to the Planets
Our Solar System
Geothermic energy is as old as
the planet, originating in the high temperatures held
within the depths of the Earth. And though its power
has been recognized by humans throughout history,
the search for new technologies aimed at using its
energy more efficiently is an ongoing challenge.
The geothermal energy that lies
beneath our feet is manifest in many ways. For example,
volcanoes, hot springs, or the furious geysers that
shoot hot water into the air.
Humans have been using the Earth's
geothermal energy for thousands of years for heat,
and even for cooking. But the more sophisticated technologies
aimed at maximizing this power began to be developed
in the past century.
Geothermal power remains an
"energy of the future" even for the Earth's inhabitants
at the beginning of the 21st century. We have yet
to take great advantage of its potential, but we already
know that it is clean, reliable, renewable - and available.
According to the International
Geothermal Association, there are some 28
countries utilizing this energy source. For many
of these nations, it remains at the experimental stages,
but there are others where geothermal energy is an
increasingly important source of heat. Iceland is
the leader in exploitation of this renewable energy.
Most of the projects using geothermal
energy are based on water-pumping devices that take
advantage of the Earth's heat to generate electricity.
The water is circulated back and reheated over and
But scientists are carrying out
research to improve efficiency and to find ways
to reach deeper into the Earth to harness the power
held by hot magma.
On the Internet, one can find
information about geothermal energy and how this "nearly
unlimited" energy source works.
and the Earth's Plumbing Systems
Geothermal Education Office
Department of Energy: Geothermal Program
Energy around the World - Map
National Laboratories - U.S.
The human immunodeficiency virus,
or HIV, was first identified 20 years ago, and has
had a major impact on human society. It is the precursor
to AIDS, a syndrome famous for its devastating effects,
as it leaves death - and often poverty - in its wake.
Since the 1980s, when the first
cases of acquired immunodeficiency syndrome (AIDS)
were recorded, the world has learned a great deal
about the disease, its causes, ways to slow the virus'
multiplication and the key to preventing the spread
of the disease: prevention.
Men are indispensable allies
for controlling the spread of HIV, say the organizers
AIDS Day, commemorated around the globe Dec 1.
The international theme this year was: "I
care… Do you?"
AIDS now exists among populations
worldwide. The latest approach to treating the disease
is a "cocktail" of medications, and it has proven
to very effective. Poor populations tend to have the
highest HIV/AIDS prevalence, and they are precisely
the ones who cannot afford the expensive medications.
Prevention remains a top priority for avoiding infection
in the first place.
Scientists at many different
institutions continue in their search for a vaccine,
but it could be years before they find one that truly
The region with highest infection
rates is Africa. In some countries of the continent,
the disease is devastating entire generations. And
beyond the social drama of HIV/AIDS, there is a major
economic challenge because the consequences of the
disease and strategies for fighting it generate enormous
costs for humanity.
Latin America and the Caribbean, the presence
of HIV/AIDS varies greatly from country to country.
Furthermore, the populations at risk are diverse.
Experts agree that these characteristics pose a unique
challenge for prevention efforts in the region.
The first step toward prevention
in all cases, however, is the same: information. And
there is nowhere on Earth that more information on
HIV/AIDS can be found than on the Internet.
Special Edition: World AIDS Day - Latin America
Joint United Nations Program on HIV/AIDS
Bank: AIDS Economics
Department of HIV/AIDS
HIV Vaccine Initiative
AIDS in the Americas
Directory of AIDS sites
Body: AIDS and HIV Information Resource