Our living planet Earth orbiting an Star Sun along with other Planet i.e our Solar System is nearly 26000 light years away from the center of our galaxy (milky way galaxy). According to one hypothesis we have a very exclusive location. There is one idea that only stars in a certain range of distances from the center of our galaxy are in so called galactic habitable zone that is able to having life in the planets around them. The overall range of galactic habitable zone extends from 13000 to 35000 light years from the center of milky way. The main part where we are ranges from 20000 to 29000 light years away from the core. In the early history of our solar system was mostly violent place. Many explosions, collisions and violent things happen at that time and formation of such a nice and calm place takes place. We know that our sun is at least second or third generation star because there are planets around it, things are made up of iron, carbons and other heavier elements. But the process that lead life to earth doesn't seems exists outside the zone(galactic habitable zone).
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| Figure: Range of galactic habitable zone of milky way |
Closer to the edge of milky way fewer massive stars were exploded producing fewer heavy elements. Further out galaxy it doesn't have as many atoms like carbon, nitrogen, oxygen the atoms are so important for the chemistry of life. So the habitable zone of our galaxy cuts off the distance where there is no heavier atoms to make life. If the outer part of our galaxy is a bad neighborhood then the inner area is even worse. Back in the time we thought that we are at the center of milky way but at the center of milky way a sucking matter and light into it there is a Sagittarius A- Star , a Black hole nearly 14 million miles across with the mass 3.7 millions time that of our Sun. There are other region in the galaxy that are also probably not great for life because there is just so much radiation from near by really hot O type stars. O type stars are giants having mass 15 to 90 times that of sun and surface temperature 30000 to 50000 kelvin and throw out titanic amount of ultraviolet radiation. With these stars you don't worry about sun burn but extinction. Its not probably easy to survive in an environment where there is lots of O type stars. O type giants can destroy planets before they form.
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| Figure: O Type Stars |
To be safe from the Radiation of O type stars we must be at least 10 light years away from it. It is possible that our kind of life can live in only galactic habitable zone. But Elsewhere there could be other kind of life that we called extreme living beings on the other hand they would call us extreme living beings.
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