Asal Usul Air
The water on Earth comes from
space ISO saw the space `water-factories' at work . Most water on Earth was not produced here - it came from space.
This is old news for astronomers, but until now water-producing factories had
not been observed at work in space. Nor was it possible to trace water at the
different stages of its long journey through space. Very little information
about cosmic water can be obtained from the ground - primarily because the
Earth's atmosphere is itself rich in water vapour and blocks our view of the
water in the Universe beyond. ISO helped astronomers to reconstruct for the
first time the cosmic cycle of water. Hydrogen (1.) was originally produced in
the Big Bang and is found everywhere in the Universe. Oxygen (2.) is made in
stars and dispersed out into the Universe in events such as supernova
explosions. The two elements mix in star-forming clouds (3.) and form large
amounts of water (H2O). The molecules of water leave the clouds and end up in
many different places (4.) - comets, planets the centres of galaxies ... When
the newly-born stars become old more oxygen is made available to the cosmic
water factory. First, the ingredients: Hydrogen is the most abundant element in
the Universe, and oxygen is produced at the centres of massive stars and
dispersed into space by stellar winds or supernova explosions. The ideal
conditions for these gases to combine are found in places such as star-forming
regions, for example, the Orion Nebula. In 1997 ISO detected large quantities
of water in Orion - the most studied star-forming region - and astronomers
estimated that the water-production rate in the nebula could fill Earth's
oceans 60 times a day. (See also ISO finds steamy cloud in
interstellar space)
Some of these newly formed water molecules start to travel out into the cold of interstellar space, where they form ice grains. With time they will end up in comets or in planets like our own. ISO has also detected water in many other regions, including the galactic centre and in both newborn and dying stars.
Some of these newly formed water molecules start to travel out into the cold of interstellar space, where they form ice grains. With time they will end up in comets or in planets like our own. ISO has also detected water in many other regions, including the galactic centre and in both newborn and dying stars.
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