Australian Politics Forum - Are we alone in the Universe?

Emma

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Re: Are we alone in the Universe?
Reply #45 - Jan 29^th, 2016 at 12:47am

John_Taverner wrote on Jan 28^th, 2016 at 8:04pm:

Ellen Stofan believes that extraterrestrial life will be discovered by 2025.

http://www.space.com/29041-alien-life-evidence-by-2025-nasa.html

I don't share his optimism. There is much more evidence that life evolved on Earth than on Mars. OK, some of the precursor chemicals may be found in comets, but not life itself, as far as we know at this time.

NASA is known for making bold claims.

That's right, the only life we know about is on Earth. I can't see what is so hard to grasp.

To say 'life' started on earth is only relative to this very small Solar System . Life as we know it.

GP , it means perfectly what it says. WE exist, and to believe Earth has the only life in this entire universe, is the thing that makes no rational sense.

I understand stretching your mind around that idea is hard, but think about it, for goodness sakes.

How homocentric of you all . You all admit, quite rightly that you don't know how life comes about. What is that thing that comes and goes without predictability? No one knows that, and to deduce that we are the only intelligent species in all entirety, completely ignores that there are other sentient beings on this very earth.

Smacks of massive self-importance and hubris.

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John_Taverner

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Re: Are we alone in the Universe?
Reply #46 - Jan 29^th, 2016 at 6:40am

Emma wrote on Jan 29^th, 2016 at 12:47am:

That's right, the only life we know about is on Earth. I can't see what is so hard to grasp.

To say 'life' started on earth is only relative to this very small Solar System . Life as we know it.

GP , it means perfectly what it says. WE exist, and to believe Earth has the only life in this entire universe, is the thing that makes no rational sense.

I understand stretching your mind around that idea is hard, but think about it, for goodness sakes.

How homocentric of you all . You all admit, quite rightly that you don't know how life comes about. What is that thing that comes and goes without predictability? No one knows that, and to deduce that we are the only intelligent species in all entirety, completely ignores that there are other sentient beings on this very earth.

Smacks of massive self-importance and hubris.

Nothing to do with self-importance. People who are smarter than you or me have been talking about it for years. The only thing that's different now is the recent discovery of hundreds of exoplanets.

Your view is simplistic. Have a read about the anthropic principle. We have a universe where life is possible. Why? Because we are here observing it. If there was a universe where life could not initiate, then nobody would be discussing it. It says nothing about how many instances of life can occur.

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The anthropic principle (from Greek anthropos, meaning "human") is the philosophical consideration that observations of the universe must be compatible with the conscious and sapient life that observes it.

There are many variants of the Anthropic principle. Read this nicely written article:
https://en.wikipedia.org/wiki/Anthropic_principle

There is also the Drake Equation. Some recent discoveries have filled in some of the unknowns but not all of them.

https://en.wikipedia.org/wiki/Drake_equation

If you want to discuss this, you would be well to do some online research into the subject.

First you need a planet in the Goldilocks zone (tick), then you need a bombardment period that was not so extreme as to destroy life in that very limited opportunity it had to establish itself. The first life relied on the anaerobic part of the Krebs cycle. There was no oxygen, so it had to use iron or sulphur as its source of energy. The clue to this is in the Oxphos cycle which is the basis of life as we know it.
https://en.wikipedia.org/wiki/Oxidative_phosphorylation

That process offers clues on how life first came about. In the NADH-coenzyme Q oxidoreductase (complex I) for example, you can still see the iron and sulphide that formed an important part of early life.

Even so, we don't know all the answers. Life could be rare or it could be very common. The proposed missions to Europa will tell us if there is life in its ice covered ocean or not. We might up with a sample of 2.

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How homocentric of you all

Don't call me that. I'm a married man. Grin

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greggerypeccary

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Re: Are we alone in the Universe?
Reply #47 - Jan 29^th, 2016 at 9:29am

Emma wrote on Jan 29^th, 2016 at 12:47am:

GP , it means perfectly what it says. WE exist, and to believe Earth has the only life in this entire universe, is the thing that makes no rational sense.

I understand stretching your mind around that idea is hard, but think about it, for goodness sakes.

There's a big difference between stretching one's mind and fantasising.

What you're doing is fantasising, while I'm remaining rational.

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Emma Gold Member Offline Australian Politics Posts: 9853 OZ Gender:	Re: Are we alone in the Universe? Reply #48 - Feb 6^th, 2016 at 11:25pm you are the one living in a tiny mind. I'll spell it out for you. What has happened once...like Earth and all our sentient species ... must be possible elsewhere. \to think otherwise is the fantasy.
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Ajax Gold Member Offline CO2 has never controlled temperature on Earth Posts: 11064 Australia Gender:	Re: Are we alone in the Universe? Reply #49 - Feb 7^th, 2016 at 9:54am Are we alone....??? I'd like to think not. But imo don't expect to find other humans on another Earth. More likely it wont even be carbon based like we are. Too many variables as to what life would look like on another planet.
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The_Barnacle Gold Member Offline Australian Politics Posts: 6205 Melbourne Gender:	Re: Are we alone in the Universe? Reply #50 - Feb 7^th, 2016 at 10:34am aquascoot wrote on Jan 27^th, 2016 at 7:52am: Loyalty should exist to your immediate social circle (about 150 people). Any concerns for people outside that 150 are really "pie in the sky, fanciful and imaginary" And there you have in a nutshell why right wingers are such violent warmongers
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The_Barnacle

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Re: Are we alone in the Universe?
Reply #51 - Feb 7^th, 2016 at 10:53am

John_Taverner wrote on Jan 28^th, 2016 at 7:36pm:

It's one thing to have the right conditions for life to survive, but the question of how life started is unknown, and we know nothing about how easy it is to start. All we know is that it commenced on Earth. We have a sample of 1.

Being scientifically minded this is a subject that i have put a lot of thought into.

The thing that i find interesting is that not only do we have a sample size of only 1 but in the 4.5 billion years that this planet has been in existence life only started once. You would imagine that on such a favourable planet that new life would be popping up all the time. Instead life started once about 3.8 billion years ago and we are all descended from that.

However there are at least 100 billion stars in our galaxy and there are at least 100 billion galaxies in the universe. Given that we now know that most stars have planets, these mind boggling numbers would suggest that even if life is extremely rare, it is still likely that it has occurred elsewhere.

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The Right Wing only believe in free speech when they agree with what is being said.

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Bobby.

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Re: Are we alone in the Universe?
Reply #52 - Feb 7^th, 2016 at 11:50am

The_Barnacle wrote on Feb 7^th, 2016 at 10:53am:

John_Taverner wrote on Jan 28^th, 2016 at 7:36pm:

It's one thing to have the right conditions for life to survive, but the question of how life started is unknown, and we know nothing about how easy it is to start. All we know is that it commenced on Earth. We have a sample of 1.

Being scientifically minded this is a subject that i have put a lot of thought into.

The thing that i find interesting is that not only do we have a sample size of only 1 but in the 4.5 billion years that this planet has been in existence life only started once. You would imagine that on such a favourable planet that new life would be popping up all the time. Instead life started once about 3.8 billion years ago and we are all descended from that.

However there are at least 100 billion stars in our galaxy and there are at least 100 billion galaxies in the universe. Given that we now know that most stars have planets, these mind boggling numbers would suggest that even if life is extremely rare, it is still likely that it has occurred elsewhere.

Yes but intelligent life is most likely to wipe itself out very quickly -
e.g nuclear weapons or a biological weapons plague -
which means that intelligent life may have developed but died out a billion years ago.

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Emma Gold Member Offline Australian Politics Posts: 9853 OZ Gender:	Re: Are we alone in the Universe? Reply #53 - Feb 8^th, 2016 at 12:27am Now THAT is a fantasy par excellence.!!
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Emma

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Re: Are we alone in the Universe?
Reply #54 - Feb 8^th, 2016 at 1:14am

The_Barnacle wrote on Feb 7^th, 2016 at 10:53am:

John_Taverner wrote on Jan 28^th, 2016 at 7:36pm:

It's one thing to have the right conditions for life to survive, but the question of how life started is unknown, and we know nothing about how easy it is to start. All we know is that it commenced on Earth. We have a sample of 1.

Being scientifically minded this is a subject that i have put a lot of thought into.

The thing that i find interesting is that not only do we have a sample size of only 1 but in the 4.5 billion years that this planet has been in existence life only started once. You would imagine that on such a favourable planet that new life would be popping up all the time. Instead life started once about 3.8 billion years ago and we are all descended from that.

However there are at least 100 billion stars in our galaxy and there are at least 100 billion galaxies in the universe. Given that we now know that most stars have planets, these mind boggling numbers would suggest that even if life is extremely rare, it is still likely that it has occurred elsewhere.

I find your second paragraph problematic.. BUT I think your ultimate conclusion is reasonable.

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aquascoot

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Re: Are we alone in the Universe?
Reply #55 - Feb 8^th, 2016 at 6:47am

The_Barnacle wrote on Feb 7^th, 2016 at 10:34am:

aquascoot wrote on Jan 27^th, 2016 at 7:52am:

Loyalty should exist to your immediate social circle (about 150 people).
Any concerns for people outside that 150 are really "pie in the sky, fanciful and imaginary"

And there you have in a nutshell why right wingers are such violent warmongers

not violent warmongers, more like dedicated to protect
"all the good they have created"

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issuevoter Gold Member Offline Australian Politics Posts: 9200 The Great State of Mind Gender:	Re: Are we alone in the Universe? Reply #56 - Feb 8^th, 2016 at 7:49am As people keep repeating the same tired old statistical certainty of life elsewhere, I will repeat the one thing about life they are not taking into account; irony. It would be ironic should we poison this planet when we do not have an alternative.
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greggerypeccary

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Re: Are we alone in the Universe?
Reply #57 - Feb 8^th, 2016 at 8:09am

Emma wrote on Feb 6^th, 2016 at 11:25pm:

I'll spell it out for you. What has happened once...like Earth and all our sentient species ... must be possible elsewhere. \to think otherwise is the fantasy.

Yes, it's possible. Nobody has said anything to the contrary.

Absolutely no reason to believe it's actually happened, though.

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Redmond Neck Gold Member Offline OzPolitic Posts: 23107 ACT Gender:	Re: Are we alone in the Universe? Reply #58 - Feb 8^th, 2016 at 8:10am "na noo na noo!'
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John_Taverner

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Re: Are we alone in the Universe?
Reply #59 - Feb 8^th, 2016 at 9:47pm

The_Barnacle wrote on Feb 7^th, 2016 at 10:53am:

John_Taverner wrote on Jan 28^th, 2016 at 7:36pm:

It's one thing to have the right conditions for life to survive, but the question of how life started is unknown, and we know nothing about how easy it is to start. All we know is that it commenced on Earth. We have a sample of 1.

Being scientifically minded this is a subject that i have put a lot of thought into.

The thing that i find interesting is that not only do we have a sample size of only 1 but in the 4.5 billion years that this planet has been in existence life only started once. You would imagine that on such a favourable planet that new life would be popping up all the time. Instead life started once about 3.8 billion years ago and we are all descended from that.

Hmmm Probably or maybe, but if you look at Ediacaran biota, it's completely different from Cambrian biota. There is no obvious connection. One group of lifeforms was wiped out, to be replaced by a second group.

The latest thinking is that there was a limited window of opportunity for life to establish, and that those conditions ceased to exist once we had oxygen in the atmosphere. The first microscopic life that we can find evidence for , apart from some questionable inclusions in metamorphic rock from Greenland, are the stromatolites from the banded ironstone formations of WA (3.5 billion years old). These represent cyanobacteria, and they were responsible for the production of oxygen leading to totally different life forms that were capable of metabolising faster. Before they came along, the atmosphere contained no oxygen. It was in this hot, hydrogen cyanide rich environment that the first living cells would have emerged.

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However there are at least 100 billion stars in our galaxy and there are at least 100 billion galaxies in the universe. Given that we now know that most stars have planets, these mind boggling numbers would suggest that even if life is extremely rare, it is still likely that it has occurred elsewhere.

Maybe, but do they have the necessary precursors? A star that is reasonably stable without too many flares, a planet with a molten (nickel) iron core that produces a magnetic shield that protects the surface from too much ionising radiation, possibly (it has been argued) even a sizeable moon with tidal systems that help to provide a system of plate tectonics.

Then there is the question of the heavier elements. Without the heavier elements from passing gases emanating from a nearby supernova, the solar system would have been deficient in those elements.

It's a subject that I find fascinating too. They claim that the next generation of orbiting infrared telescopes will be able to resolve the atmospheres of some of these exoplanets.

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« Last Edit: Feb 8^th, 2016 at 9:55pm by John_Taverner »

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