cyberdad wrote:
BaalChatzaf wrote:
cyberdad wrote:
Hawking also warned that the Pioneer spacecraft will attract malevolent aliens to attack Earth.
https://en.wikipedia.org/wiki/Pioneer_plaqueIt's interesting the humans pictured on the image greeting aliens represent the 15% of the human population who rule over the other 85%
So rather than malevolent the aliens might think they saving the 85% of the human race from their Caucasian overlords
Or none of the above. Our Pioneer vehicle is not even a tenth of the way to the closest star (other than the sun). The chance of any intelligent being picking it up AND making sense out of it is virtually zero.
Logic dictates the probability that life only evolved once in the entire known universe is impossible. Given that earth like planets evolved billions of years before our own earth means other life forms have evolved beyond our simple organic forms and are most likely "post-biological" existing outside of time and space. Such sentient beings are not only aware we exist (which means Pioneer was a waste of time) but consider us the same way we might consider a lone E.coli bacteria swimming in the Pacific ocean...
It is unlikely that many Earth-like planets could have evolved very many billions of years before the Earth.
The Universe is estimated to be approximately 14 billion years old and the Earth is about 4.5 billion years old. That may make it sound like there were 9.5 billion years for Earth-like planets to form before us, but that ignores the actual science.
No Earth-like planet could possibly have formed around any of the first generation of stars for the simple reason that many of the elements we have today had not yet formed. It took exploding stars in the forms of supernovas to make a great deal of the elements found in the Earth. It is true that some elements can be created inside a star, but not all of the ones we have on Earth and not in as much abundance. Only a supernova can do that.
Many of the elements on the Earth were created by a supernova. Thus, for the Earth to have formed at all, there had to have been previous stars in the area that used up all their fuel for nuclear fusion and then progressed to become supernovas in order to create the materials that could be used to form an Earth-like planet.
For what it's worth, I read somewhere once that the first generation of stars would not have been able to form supernovas. I don't remember the reasoning for the comment, but if it is true, then it would take a third generation star to have an Earth-like planet.
04 Dec 2016, 7:14 pm
