Bringing the alien life debate back to reality

[Truth Detector]

This is sort of an odd response.

I don't want to assume anything. Is your contention that in the vastness of the universe, where there are trillions of stars and even more planets - the only life anywhere is on earth?

That is my contention. Prove me wrong snowflake.

[Saint Guinefort]

That is my contention. Prove me wrong snowflake.

Normally it is not required to "prove a negative" since most of the time that is impossible. One cannot prove there is "no life in the universe except on earth". All of these discussions are really little more than playing the odds.

Life is pretty normal regular "jive old" chemistry. We find a lot of the organic molecules we see on earth also in meteorites. So it stands to reason that, given the entire size of the universe, the utter vastness of it, and the fact that the chemistry is pretty straightforward that life probably exists in many places.

[Doc Dutch]

Normally it is not required to "prove a negative" since most of the time that is impossible. One cannot prove there is "no life in the universe except on earth". All of these discussions are really little more than playing the odds.

Life is pretty normal regular "jive old" chemistry. We find a lot of the organic molecules we see on earth also in meteorites. So it stands to reason that, given the entire size of the universe, the utter vastness of it, and the fact that the chemistry is pretty straightforward that life probably exists in many places.

...and it'll be an exciting day IF mankind ever finds it.

[Cypress]

The headline is misleading but:


https://autos.yahoo.com/scientists-f...193000684.html

Your own article says even if this technology is ever feasible, it still won't allow faster than light travel:

If this could become a reality, don’t expect instant travel across space to happen right away, as Vice explains:

“Unlike fictional wormholes, the experimental version would not allow for instantaneously faster-than-light travel to distant locations, because counterportation crawls along much more slowly than the speed of light.

[Cypress]

...and it'll be an exciting day IF mankind ever finds it.

Before I leap to the conclusion that life is inevitable in the presence of liquid water, I'd like to see evidence that life emerged more than once in four billion years on earth.

Once in four billion years almost sounds like a fluke or an extremely rare occurrence to me.

In the last decade we have become aware of a vast deep biosphere in the Earth's crust, miles below the surface. I think it would be one of the great scientific discoveries of the century to find life forms there which have a separate genetic legacy from all the known life that descended from LUCA.

[Doc Dutch]

Before I leap to the conclusion that life is inevitable in the presence of liquid water, I'd like to see evidence that life emerged more than once in four billion years on earth.

Once in four billion years almost sounds like a fluke or an extremely rare occurrence to me.

In the last decade we have become aware of a vast deep biosphere in the Earth's crust, miles below the surface. I think it would be one of the great scientific discoveries of the century to find life forms there which have a separate genetic legacy from all the known life that descended from LUCA.

While life may, indeed, be inevitable, it appears to be extremely rare. As such, there may not be any previous life forms to LUCA.

One thing that does seem clear is that once life takes hold, it's very difficult to eradicate.

[Cypress]

While life may, indeed, be inevitable, it appears to be extremely rare. As such, there may not be any previous life forms to LUCA.

One thing that does seem clear is that once life takes hold, it's very difficult to eradicate.

Agree. for existing life, descent with modification by natural selection and gene drift is robust and nearly impervious to any kind of fatal knock out blow.

[Doc Dutch]

Agree. for existing life, descent with modification by natural selection and gene drift is robust and nearly impervious to any kind of fatal knock out blow.

Finding life off planet keeps running into the Fermi Paradox. If life is inevitable, where is it?

Based upon the results, there seem to be two main conclusions: Life is rare and the interstellar distances between lifeforms is vast.

Have you ever visited a "The Voyage" display? I saw the one in Corpus Christi. It really nails the vastness of "Space".

http://voyagesolarsystem.org/

http://voyagesolarsystem.org/the-experience/

[BartenderElite]

That is my contention. Prove me wrong snowflake.

I'm not going to prove you wrong - but you can't prove me wrong, either.

It's odd to ridicule the mere idea that there could be other life in a universe where there are over a trillion galaxies, each with roughly 100 billions stars. I don't know how someone could believe - without any doubt at all - that earth is the only planet with life in all of that vastness.

I'm curious - is it a religious thing? Does it threaten anyone's beliefs to think (quite logically) that there could not only be life elsewhere in the universe, but that it might be pretty abundant?

[Doc Dutch]

I'm not going to prove you wrong - but you can't prove me wrong, either.

It's odd to ridicule the mere idea that there could be other life in a universe where there are over a trillion galaxies, each with roughly 100 billions stars. I don't know how someone could believe - without any doubt at all - that earth is the only planet with life in all of that vastness.

I'm curious - is it a religious thing? Does it threaten anyone's beliefs to think (quite logically) that there could not only be life elsewhere in the universe, but that it might be pretty abundant?

The religion thing has an inherent problem: If they go strictly by the Bible, then life only exists on Earth. If they truly believe that God is all powerful, then they can't deny God could put life on every planet in the Universe.

There's also the problem of Jesus; did Jesus die for all the space alien's sins too? Or did he have to be executed on every planet with life?

[Cypress]

Finding life off planet keeps running into the Fermi Paradox. If life is inevitable, where is it?

Based upon the results, there seem to be two main conclusions: Life is rare and the interstellar distances between lifeforms is vast.

Have you ever visited a "The Voyage" display? I saw the one in Corpus Christi. It really nails the vastness of "Space".

http://voyagesolarsystem.org/

http://voyagesolarsystem.org/the-experience/

Nice. I don't think the human mind evolved to be able to intuitively comprehend distances like that.

The Fermi paradox seems to boil down to a couple simple questions:

Is life a chemical law of the universe; does it inevitably emerge in the presence of liquid water?

Or is life almost a fluke, something which required a perfect storm of chemical, physical, and cosmological events which are only very rarely replicated.

[Doc Dutch]

Nice. I don't think the human mind evolved to be able to intuitively comprehend distances like that.

The Fermi paradox seems to boil down to a couple simple questions:

Is life a chemical law of the universe; does it inevitably emerge in the presence of liquid water?

Or is life almost a fluke, something which required a perfect storm of chemical, physical, and cosmological events which are only very rarely replicated.

Agreed on the inability of the human mind to fully grasp the distances involved.

Fluke appears to be the best candidate, IMO. Life is a very rare event.

Still, in a galaxy with 100B stars and a Universe with over 100B galaxies, the odds seem good that the fluke has occurred elsewhere.

https://solarsystem.nasa.gov/solar-s...yond/overview/

Our Milky Way galaxy is just one of the billions of galaxies in the universe. Within it, there are at least 100 billion stars, and on average, each star has at least one planet orbiting it. This means there are potentially thousands of planetary systems like our solar system within the galaxy!...

...Our Sun is one of at least 100 billion stars in the Milky Way, a spiral galaxy about 100,000 light-years across. And where are we in the Milky Way? Our Sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms.

https://www.skyatnightmagazine.com/s...s-in-universe/

One such estimate says that there are between 100 and 200 billion galaxies in the observable universe.

Other astronomers have tried to estimate the number of ‘missed’ galaxies in previous studies and come up with a total number of 2 trillion galaxies in the universe.

However, based on recent measurements of the darkness of the night sky, this may be an overestimate.

[Cypress]

Agreed on the inability of the human mind to fully grasp the distances involved.

Fluke appears to be the best candidate, IMO. Life is a very rare event.

Still, in a galaxy with 100B stars and a Universe with over 100B galaxies, the odds seem good that the fluke has occurred elsewhere.

https://solarsystem.nasa.gov/solar-s...yond/overview/


https://www.skyatnightmagazine.com/s...s-in-universe/

Absent any compelling evidence, I am on Team rare life myself.

I've never been that impressed with the math of a hundred billion stars in the Milky Way and a hundred million galaxies.

It's not the sheer number that matter.

We live in a very large and complex galaxy. If we can't find evidence of life in this galaxy, I see no reason to expect it to be in other galaxies.

Many galaxies and many stars are depleted in heavy elements, which are required for life.

None of the blue giants or Red supergiant stars would be expected to have planets with life, those stars don't live very long.

The white dwarfs are the dead embers of sun-like stars, I wouldn't expect life there.

As for the red dwarfs and G type stars, how many of them are depleted in heavy elements, and how many are in potentially gravitationally unstable binary and trinary systems? Solo stars like our sun tend to be the exception rather than the rule. And of those, how many have rocky planets with a magnetic field in the Goldilocks habitable zone of it's star's orbit?

So the number of potentially habitable star systems in our galaxy probably gets whittled way down from 100 billion. And the percentage of those that have intelligent life probably whittled it way down from there.

[Saint Guinefort]

Absent any compelling evidence, I am on Team rare life myself.

I've never been that impressed with the math of a hundred billion stars in the Milky Way and a hundred million galaxies.

It's not the sheer number that matter.

We live in a very large and complex galaxy. If we can't find evidence of life in this galaxy, I see no reason to expect it to be in other galaxies.

Many galaxies and many stars are depleted in heavy elements, which are required for life.

None of the blue giants or Red supergiant stars would be expected to have planets with life, those stars don't live very long.

The white dwarfs are the dead embers of sun-like stars, I wouldn't expect life there.

As for the red dwarfs and G type stars, how many of them are depleted in heavy elements, and how many are in potentially gravitationally unstable binary and trinary systems? Solo stars like our sun tend to be the exception rather than the rule. And of those, how many have rocky planets with a magnetic field in the Goldilocks habitable zone of it's star's orbit?

So the number of potentially habitable star systems in our galaxy probably gets whittled way down from 100 billion. And the percentage of those that have intelligent life probably whittled it way down from there.

In the Milky Way NASA guesses there are something like 4.1billion sun-like stars and they further estimate that of these stars 300 million of them have "habitable" planets (MIT). I would think that advanced life would definitely have been detectable by this point assuming they could generate a signal we could receive. Maybe advanced life is super rare but simple life is really common.

The probabilities are multiplicative and going from development of simple life to development of advanced technological life is what makes it much more rare. Maybe we share the galaxy with 300million planets that look like the Earth when stromatolites ruled.

[Cypress]

In the Milky Way NASA guesses there are something like 4.1billion sun-like stars and they further estimate that of these stars 300 million of them have "habitable" planets (MIT). I would think that advanced life would definitely have been detectable by this point assuming they could generate a signal we could receive. Maybe advanced life is super rare but simple life is really common.

The probabilities are multiplicative and going from development of simple life to development of advanced technological life is what makes it much more rare. Maybe we share the galaxy with 300million planets that look like the Earth when stromatolites ruled.

That corroborates precisely what I wrote.

Rather than tossing around the admitedly impressive 100 billion number, the actual amount of possibly habitable stars is only a tiny fraction of one percent of those.

And that doesn't even include estimates for how many of those actually have rocky planets with magnetic fields or a large lunar companion, and within the Goldilocks zone which are critical to all life on earth .