CHAPTER 1-LIFE OUTSIDE EARTH
It is estimated by Astronomers that in the Milky Way galaxy there are about 100 thousand million stars. The Milky Way galaxy is only one of the millions upon millions of galaxies estimated throughout the known universe. Therefore it is blatantly obvious that there must be some form of life elsewhere in the universe. As we begin to explore our own small part or this galaxy we make discovery after discovery that points to life not only existing somewhere far away but actually at lot closer to home than we have previously been taught.
Gliese 581 C
In April 2007 an earth like planet was found outside our solar system. The planet has been named Gliese 581 C. Computer models show that the planet is either covered entirely by oceans or is a rocky planet like Earth. The temperature has been estimated to be between 0 and 40 degrees Celsius and so water would remain in its liquid state.
It has been discovered that Venus and Earth both had extremely similar climates when they started out as planets. A report in the journal Nature tells how since Venus has a lack of a magnetic field solar wind stripped away water by breaking H2O into oxygen and hydrogen atoms that then left the atmosphere. It is thought that in Venus’s early life it would of even been habitable.
A meteorite was discovered in 1984 named ALH84001 that was confirmed as coming from mars. NASA scientists discovered that ALH84001 had carbonate rosettes similar to the rosettes made by bacteria on Earth as they metabolise minerals. Chemical compounds called polycyclic aromatic hydrocarbons were also found and they concluded that they might have been produced as once-living organisms decomposed. Tiny crystals of magnetite and iron sulfide were also embedded in places where the carbonate rosettes had dissolved some bacteria on Earth also manufacture these crystals. Using an electron microscope NASA scientists found elongated and egg-shaped structures within the carbonate rosettes, which were believed to be tiny fossils of Martian microbes.
In 2003 methane was detected in the Martian atmosphere leading to the conclusion that perhaps life may be the cause of this methane since most methane (over 90%) on Earth is produced by living things,
In 2008 NASA's Phoenix Mars Lander confirmed that Martian soil contains magnesium and potassium and has a slightly alkaline pH and most importantly that water was indeed present on Mars.
So given the enormous amount of planets and the vastness of the universe plus the fact that our own solar system has provided us with so much evidence in support of ET life existing we must now believe that life of some form must exist somewhere in our ever changing universe.
ESA space science-How many stars are there in the Universe?
BBC News- New 'super-Earth' found in space
Sky mania News -Was wet Venus once home to life?
NOVA Science In The News- Life on Mars?