Post by Titanis on Aug 4, 2009 19:01:53 GMT 1
Probably one of humanity's most fundamental questions. Are we alone in the universe? Are we alone in our own galaxy? What do you think?
I personally think that it's highly improbable that Earth is the only planet in the whole entire universe - or even in just the Milky Way galaxy - that has life on it. In our galaxy alone there is some 100,000,000,000 or more stars (that's 100 billion!). The universe contains so many galaxies (some like our own) that it's hard to even imagine how many there are. So how could our Sun, this one G-class main sequence star at about the middle point in it's life time have been the only one to spawn a planet in its habitable zone (that's the area around a star where it is possible for liquid water to exist on the surface). There are many other G-class and K-class (K is also capable of sustaining life), in our Galaxy. There are more galaxies in the universe than grains of sand on all the beaches on Earth.
So I don't think we are that special. I think it would be much stranger to discover that we are the only planet with life in the entire universe. I think it is much more likely that life has arisen many times in many places throughout our galaxy and the universe.
So to end my post I'll leave you with a picture from the Hubble Space Telescope called the "Ultra Deep Field." It is arguably the most important picture taken by mankind:
This picture was taken over a small, unremarkable patch of sky. There are over 10,000 galaxies in it, each with millions or billions of their own stars. And each star has the possibility of planets, and life. So you tell me how it's possible that the only place life as arisen is here on Earth...
I personally think that it's highly improbable that Earth is the only planet in the whole entire universe - or even in just the Milky Way galaxy - that has life on it. In our galaxy alone there is some 100,000,000,000 or more stars (that's 100 billion!). The universe contains so many galaxies (some like our own) that it's hard to even imagine how many there are. So how could our Sun, this one G-class main sequence star at about the middle point in it's life time have been the only one to spawn a planet in its habitable zone (that's the area around a star where it is possible for liquid water to exist on the surface). There are many other G-class and K-class (K is also capable of sustaining life), in our Galaxy. There are more galaxies in the universe than grains of sand on all the beaches on Earth.
So I don't think we are that special. I think it would be much stranger to discover that we are the only planet with life in the entire universe. I think it is much more likely that life has arisen many times in many places throughout our galaxy and the universe.
So to end my post I'll leave you with a picture from the Hubble Space Telescope called the "Ultra Deep Field." It is arguably the most important picture taken by mankind:
This picture was taken over a small, unremarkable patch of sky. There are over 10,000 galaxies in it, each with millions or billions of their own stars. And each star has the possibility of planets, and life. So you tell me how it's possible that the only place life as arisen is here on Earth...