"Nowadays, we have discovered an elegant and efficient way of understanding the universe: a
method called science. This method has revealed us an universe so vast and antique that human affairs seem to
be meaningless at first sight. We have been moving so far away from the Cosmos till it looks like something remote
and with no important consequences to our everyday worries. But science not only has discovered that the
universe has a greatness that inspires ecstasy and vertigo, an accessible greatness to human comprehension,
but also that we are a part of this Cosmos in a deep and real sense, that we are born from it and that our destiny
depends from it in an intimate
way."
Carl Sagan.
The Cosmos
Our place in the universe is a small planet that turns around a medium star, located in the arm of
an enormous galaxy, another one of the countless ones that exist in the universe. From our natal world, we
stare at the space and contemplate the wonders of the cosmos. Close to the Earth we can find the planets and
other bodies of the solar system, orbiting our familiar Sun; in the distance we can see the other stars of our
galaxy, some of them bright and hot, others small and pale. 
We can observe gas clouds from where emerge the
stars and perceive strange phenomenons that indicate the enigmatic emptiness left by the stars dead in violent
cataclysms and pushing the astronomical instruments to its limits, scientists research how could the universe have
been initiated and how would it be its end.
For a long time we have known that our home, the Earth, is a flatted football shaped planet that rotates over its own
axis once a day and rotates around the Sun once a year. In the equatorial zone, the rotation velocity gets close to
1.600 km/h, and the velocity of its orbit around the Sun aproximates to 107.000 km/h. The Earth has an axis that is
inclined with respect to its orbit line. This makes the Sun to be high in the sky during midday, and low in other
occasions. The four seasons constantly remind us of this inclination, cause the Sun travels high during summer and
low during the winter season. The Earth has a width of 12.760 km, though the zone we live in has less than 5 km.
In the center of oceanic areas there are huge volcanic mountains from where the basalt comes out, a kind of rock
that forms enormous "plates". Guided by the convexion currents of the emerging material from the Earth's melted
interior, the basalt arises slowly causing a marine bed expansion and a plate displacement. These plates moves
over the underlying material about a few cm per year. Earth continents are gigantic rafts with a thickness up to 160
km, deposited over the highest part of the plates. The volcanic eruption gas emissions that happened millions of
years ago, gave to the Earth its initial atmosphere that it's been changing its own composition due to geological
action and to the conversion of carbon dioxide into oxygen made by the plants. The composition of the air has
been stablished in 77% of nitrogen, 21% of oxygen, 1% wa ter steam and small amounts of argon, carbon dioxide,
neon, helium and sulphur. The gravitational field is strong enough to prevent the atmosphere to escape to the
outter space.
The evidence collected from the fossils suggests that life has existed in Earth for thousands of millions of years,
and that it has changed and has gradually developed as time passes by. When the Earth was young -4 thousand
millions of years ago- its temperature was too high for lodging any kind of live, and its surface was bombarded by
meteors. Little by little it was cooling and a cape of water was created. Life could have been created in this global
ocean. Life was possible only when a lucky strike united a chemical compound able to make copies of itself. It
atracted its own components as a chain of magnets, lining them up in order to form a new chain. In its own turn this
chain was liberated to make copies of itself.
The beings can reproduce theirselves very quickly until the resources become limited. When this happend, all
life forms must fight to survive. The ways of gaining advantages include sharing life with other species; finding
new food sources; and cheating predators with a camouflage. This "eliminate the weakest" process is known as
natural selection and still is evolution's angular stone.
The combination of abundant water and protector atmosphere cannot be found in any other planet orbiting our
Sun. But the fact of Earth's unique characteristics in our solar system does not include our galaxy. If only a few
planets orbiting distant stars were similar to the Earth, the number of these with favorable characteristics could rise
to several millions. If life has been developed in some of these planets, and if some of these has reached some
intelligence life form, are questions that still wait to be answered.
The Sun is a gas globe principally conformed by hydrogen, with a great proportion of helium. In spite of being
109 times bigger than the Earth, with a diameter of 1.392.500 km, 
is small compared with the star average. The
center of the Sun is incredibly hot -close to 15 millions degrees Celsius- and this temperature reduces the atoms to
its nucleus. Then, the center is a dense and congested sea of very small nuclear particles called protons. When
two protons get together, they initiate a chain of events that transform them into helium and they start to liberate an
extraordinary amount of energy. Such energy principally appears in the form of short wave gamma radiation and
X rays. In the center of the Sun, the gas atom's nucleous absorb and then expel plenty of this radiation in their way
to the exterior. 600.000 km away from the center of the Sun, the gas is much colder. Helium and hydrogen normal
atoms can assume their shape and energy appears principally in the form of light an heat.
The Sun brings energy to a process of the plants called photosynthesis, through wich it transforms Sun's primary
energy into glucose, a source that activates the alimentary chain from where almost any kind of life form on Earth
depends. We use the rests of plants transformed by sunlight millions of years ago, as fossil combustibles -charcoal
and oil. The Sun generates energy at an enormous rhythm. Inclusively at such a distance away from the Sun as we
are -an average of 150 millions of km-, we receive an amount of energy equivalent to 1,4 kilowatt per square meter.
The equatorial zone gets warmer than the poles. The climate is a system that distribute heat from warmest regions.
The Sun directs the winds and evaporates the water that later falls as rain or snow in highest lalitudes.
The four nearest planets to the Sun are so similar that they are called terrestrial planets, because just like the Earth,
they are made of rock. The closest to the Sun, Mercury, never could preserve its atmosphere because it is very
small. Venus is big enough to keep its atmosphere, but too close to the Sun in order to keep its water in liquid state.
Mars, the smallest one and the most faraway from the Sun, is cold and desolated with a thin atmosphere. Only Earth
has the appropriate size and distance with respect to the Sun in order to preserve enough atmosphere that allow
the necessary temperature to support life.
Although Jupiter, Saturn, Uranus and Neptune have solid nucleus, they are so far away from the Sun that they
have kept their dense, thick and dangerous gas cover. Pluto is the most distant from the Sun of the outter planets, is
the one that presents less similitudes; is a small ice sphere that looks more like an asteroid than a planet.
The satellites, or planet's moons present theirselves in a huge variety. Equally to the planets they orbit around, the
satellites form two different groups: the high density and rocky ones -from Mercury to Mars- and the ones made of
rock and ice -from Jupiter till the exterior solar system. One of the biggest satellites in our solar system is Titan,
from Saturn. This is the only one that has an atmosphere and seems to be partially covered by an ocean, probably
liquid ethane. Lately it has been discovered what it seems to be an ocean in liquid state under ice capes, in the
surface of Jupiter's moon Europa.
Beyond the interior planets exists a ring of rocky residues that orbit the Sun between Mars and Jupiter. Some of
these residues are huge -the biggest body, named Ceres, has almost 1.000 km wide-, but the most part of the
already known bodies have only a few km wide. These are called asteroids, or minor planets. From time to time the
interior solar system receives from exterior places in the form of comets. The comets look like huge and dusty
snowballs. When their orbit get them closer to the Sun, the surface vaporizates and the dust mixed with ice
unfastens from the surface in order to form a tale that shines with the reflected sunlight. When the Earth chashes
against the tale of a comet, fragile and breakable dust particles make contact with air molecules. These particles
are known as falling stars or meteor.
We can look outside our galaxy to see millions of other galaxies all over the universe; possibly 50.000 millions or
even more. What we call Milky Way is the galaxy seen from its interior. Our location in one of the spiral arms
gives us a preferential view. Besides of bright gas clouds where stars are born, there are bunches of stars and
dark dust bands. All these things are signs of a young and flourishing galaxy, and of the permanent new star
creation. The dust disperses the light the same way that our atmosphere's molecules do with the sunlight, to give
the blue color to the sky. These dust regions can become fragmented into small areas that begin to shrink and form
stars. To observe other galaxies we must see to the sides, in right angles from the Milky Way, where we find less
dust and stars blocking our vision. Our galaxy and other couple of dozens, form the Local Group of galaxies. Such
groups are always denominated by huge eliptical galaxies, each one containing maybe 500.000 millions of stars,
five times the number of stars in our galaxy.
The stars death can be compared to their lives. The stars with more mass end like supernovas in spectacular
explotions, meanwhile a smaller star like our Sun will transform into a red and dilated giant approximately in 5.000
millions of years, before collapse and become a white small one. The red small ones simply put out theirselves at the
end of their lives. When a star with the size of the Sun consume all of its combustible, it starts to reorganize itself
freeing huge capes of matter, that rise to the space as planet nebulas leaving only the burning center. In a distant
future, when the Sun turn itself into a red giant, the Earth will be incinerated.
Astrophysics sostain that black hole's matter is so highly compressed that its gravity turns irresistible. A black hole
with the size of the sun would have more than 1.000 million times the matter of the Sun itself. The gravitational force
of a black hole of this size would be so huge that anything located within its range would be absorbed into its dark
heart inexorably. Not even light would be able to escape. That's why it is known as black hole. But the most
massive black holes can associate theirselves with mysterious objects called quasars, the most intensive sources of
energy in the universe, as bright as one hundred galaxies although they are not bigger than our solar system.
Most part of the astrophysics accept the theory that the universe started with the biggest explotion of all times,
named the Big Bang. Long ago only existed an unimaginable small and hot sphere, even smaller than
an atom. A moment later, the universe exploted towards its existence, with an impact of such proportions that even
today we find material moving away at amazing speeds in every direction. One of the best verification is obtained
when we observe the light of far objects. The light moves towards red extreme of the spectral when the observed
object moves away from the observer. This displacement towards red color detected in the light of each distant
galaxy, super cumulus or quasar, shows that they are moving away from us and also between them. A concluding
evidence of this scenario is the brightness still detected in any 
direction we stare at, known as background's
radiation microwaves.
While stars like the Sun die, new stars are born, but the process cannot continue forever. After 100 billion years
there won't be any gas left to form new stars and the last small red stars will be ashes. Finally, all the stars of the
universe will be reduced to a dark and cold matter piece. Besides, although in these moments the universe is still
expanding, it is not guarantied that it will keep doing it indefinably.
Cosmic Links
We can observe gas clouds from where emerge the
stars and perceive strange phenomenons that indicate the enigmatic emptiness left by the stars dead in violent
cataclysms and pushing the astronomical instruments to its limits, scientists research how could the universe have
been initiated and how would it be its end.
For a long time we have known that our home, the Earth, is a flatted football shaped planet that rotates over its own
axis once a day and rotates around the Sun once a year. In the equatorial zone, the rotation velocity gets close to
1.600 km/h, and the velocity of its orbit around the Sun aproximates to 107.000 km/h. The Earth has an axis that is
inclined with respect to its orbit line. This makes the Sun to be high in the sky during midday, and low in other
neon, helium and sulphur. The gravitational field is strong enough to prevent the atmosphere to escape to the
outter space.
The evidence collected from the fossils suggests that life has existed in Earth for thousands of millions of years,
and that it has changed and has gradually developed as time passes by. When the Earth was young -4 thousand
millions of years ago- its temperature was too high for lodging any kind of live, and its surface was bombarded by
meteors. Little by little it was cooling and a cape of water was created. Life could have been created in this global
ocean. Life was possible only when a lucky strike united a chemical compound able to make copies of itself. It
atracted its own components as a chain of magnets, lining them up in order to form a new chain. In its own turn this
chain was liberated to make copies of itself.
The beings can reproduce theirselves very quickly until the resources become limited. When this happend, all
life forms must fight to survive. The ways of gaining advantages include sharing life with other species; finding
new food sources; and cheating predators with a camouflage. This "eliminate the weakest" process is known as
natural selection and still is evolution's angular stone.
The combination of abundant water and protector atmosphere cannot be found in any other planet orbiting our
Sun. But the fact of Earth's unique characteristics in our solar system does not include our galaxy. If only a few
planets orbiting distant stars were similar to the Earth, the number of these with favorable characteristics could rise
to several millions. If life has been developed in some of these planets, and if some of these has reached some
intelligence life form, are questions that still wait to be answered.
The Sun is a gas globe principally conformed by hydrogen, with a great proportion of helium. In spite of being
109 times bigger than the Earth, with a diameter of 1.392.500 km, 
is small compared with the star average. The
center of the Sun is incredibly hot -close to 15 millions degrees Celsius- and this temperature reduces the atoms to
its nucleus. Then, the center is a dense and congested sea of very small nuclear particles called protons. When
two protons get together, they initiate a chain of events that transform them into helium and they start to liberate an
extraordinary amount of energy. Such energy principally appears in the form of short wave gamma radiation and
X rays. In the center of the Sun, the gas atom's nucleous absorb and then expel plenty of this radiation in their way
to the exterior. 600.000 km away from the center of the Sun, the gas is much colder. Helium and hydrogen normal
atoms can assume their shape and energy appears principally in the form of light an heat.
The Sun brings energy to a process of the plants called photosynthesis, through wich it transforms Sun's primary
energy into glucose, a source that activates the alimentary chain from where almost any kind of life form on Earth
depends. We use the rests of plants transformed by sunlight millions of years ago, as fossil combustibles -charcoal
and oil. The Sun generates energy at an enormous rhythm. Inclusively at such a distance away from the Sun as we
are -an average of 150 millions of km-, we receive an amount of energy equivalent to 1,4 kilowatt per square meter.
The equatorial zone gets warmer than the poles. The climate is a system that distribute heat from warmest regions.
The Sun directs the winds and evaporates the water that later falls as rain or snow in highest lalitudes.
The four nearest planets to the Sun are so similar that they are called terrestrial planets, because just like the Earth,
they are made of rock. The closest to the Sun, Mercury, never could preserve its atmosphere because it is very
small. Venus is big enough to keep its atmosphere, but too close to the Sun in order to keep its water in liquid state.
Mars, the smallest one and the most faraway from the Sun, is cold and desolated with a thin atmosphere. Only Earth
has the appropriate size and distance with respect to the Sun in order to preserve enough atmosphere that allow
the necessary temperature to support life.
Although Jupiter, Saturn, Uranus and Neptune have solid nucleus, they are so far away from the Sun that they
have kept their dense, thick and dangerous gas cover. Pluto is the most distant from the Sun of the outter planets, is
the one that presents less similitudes; is a small ice sphere that looks more like an asteroid than a planet.
The satellites, or planet's moons present theirselves in a huge variety. Equally to the planets they orbit around, the
satellites form two different groups: the high density and rocky ones -from Mercury to Mars- and the ones made of
rock and ice -from Jupiter till the exterior solar system. One of the biggest satellites in our solar system is Titan,
from Saturn. This is the only one that has an atmosphere and seems to be partially covered by an ocean, probably
liquid ethane. Lately it has been discovered what it seems to be an ocean in liquid state under ice capes, in the
surface of Jupiter's moon Europa.
Beyond the interior planets exists a ring of rocky residues that orbit the Sun between Mars and Jupiter. Some of
these residues are huge -the biggest body, named Ceres, has almost 1.000 km wide-, but the most part of the
already known bodies have only a few km wide. These are called asteroids, or minor planets. From time to time the
interior solar system receives from exterior places in the form of comets. The comets look like huge and dusty
snowballs. When their orbit get them closer to the Sun, the surface vaporizates and the dust mixed with ice
unfastens from the surface in order to form a tale that shines with the reflected sunlight. When the Earth chashes
against the tale of a comet, fragile and breakable dust particles make contact with air molecules. These particles
are known as falling stars or meteor.
We can look outside our galaxy to see millions of other galaxies all over the universe; possibly 50.000 millions or
even more. What we call Milky Way is the galaxy seen from its interior. Our location in one of the spiral arms
gives us a preferential view. Besides of bright gas clouds where stars are born, there are bunches of stars and
dark dust bands. All these things are signs of a young and flourishing galaxy, and of the permanent new star
creation. The dust disperses the light the same way that our atmosphere's molecules do with the sunlight, to give
the blue color to the sky. These dust regions can become fragmented into small areas that begin to shrink and form
stars. To observe other galaxies we must see to the sides, in right angles from the Milky Way, where we find less
dust and stars blocking our vision. Our galaxy and other couple of dozens, form the Local Group of galaxies. Such
groups are always denominated by huge eliptical galaxies, each one containing maybe 500.000 millions of stars,
five times the number of stars in our galaxy.
The stars death can be compared to their lives. The stars with more mass end like supernovas in spectacular
explotions, meanwhile a smaller star like our Sun will transform into a red and dilated giant approximately in 5.000
millions of years, before collapse and become a white small one. The red small ones simply put out theirselves at the
end of their lives. When a star with the size of the Sun consume all of its combustible, it starts to reorganize itself
freeing huge capes of matter, that rise to the space as planet nebulas leaving only the burning center. In a distant
future, when the Sun turn itself into a red giant, the Earth will be incinerated.
Astrophysics sostain that black hole's matter is so highly compressed that its gravity turns irresistible. A black hole
with the size of the sun would have more than 1.000 million times the matter of the Sun itself. The gravitational force
of a black hole of this size would be so huge that anything located within its range would be absorbed into its dark
heart inexorably. Not even light would be able to escape. That's why it is known as black hole. But the most
massive black holes can associate theirselves with mysterious objects called quasars, the most intensive sources of
energy in the universe, as bright as one hundred galaxies although they are not bigger than our solar system.
Most part of the astrophysics accept the theory that the universe started with the biggest explotion of all times,
named the Big Bang. Long ago only existed an unimaginable small and hot sphere, even smaller than
an atom. A moment later, the universe exploted towards its existence, with an impact of such proportions that even
today we find material moving away at amazing speeds in every direction. One of the best verification is obtained
when we observe the light of far objects. The light moves towards red extreme of the spectral when the observed
object moves away from the observer. This displacement towards red color detected in the light of each distant
galaxy, super cumulus or quasar, shows that they are moving away from us and also between them. A concluding
evidence of this scenario is the brightness still detected in any 
direction we stare at, known as background's
radiation microwaves.
While stars like the Sun die, new stars are born, but the process cannot continue forever. After 100 billion years
there won't be any gas left to form new stars and the last small red stars will be ashes. Finally, all the stars of the
universe will be reduced to a dark and cold matter piece. Besides, although in these moments the universe is still
expanding, it is not guarantied that it will keep doing it indefinably.
New Space Network