For Shanglan: What if we had no Moon

[amicus]

This is a follow-up for those who questioned some of the assertions made in my thread concerning, "What if..."




Keyword search: discovery science without a moon

http://shopping.discovery.com/product-52214.shtml

What would life on earth be like without the moon? Well, chances are, there wouldn't be any life on earth without the moon. Life – if it had started at all – would still be in the earliest stages of evolution.

Scientists use the latest computer simulations to show how an ancient rogue planet – Orpheus – collided with the earth millions of years ago, producing a sizable chunk of debris that eventually became our moon. If that collision had never occurred, we would live in a very different place. Imagine a moon-less weather report – blizzards over the Sahara, floodwaters swallowing the Pyramids, 90-degree temperatures in Antarctica. As the earth wobbles on its axis – unsecured by the moon's gravitational pull – the polar caps would grow and recede at frightening rates. And without the moon, our planet would spin much faster – meaning four-hour days and searing temperatures.

Worse yet, evidence reveals that we are in fact losing our grip on our lunar friend thanks to the ebb and flow of the oceans' tides. Experts reveal theories for salvaging the moon – including hijacking Europa from Jupiter – and demonstrate how we can prepare ourselves for our eventual life without it.

Second keyword search: discovery science if we had no moon

http://www.christinelavin.com/discuss/messages/47.html

"If We Had No Moon", August 30, 2000
Reviewer: Michael J. Zajic (see more about me) from Bethesda, MD USA

This natural science video is one of the most beautiful and exiciting of the "planetary" videos. Unfortunately, it is currently out of production and not for sale except maybe as a used video.

The science and visual technical effects and the animations are stunning and convey the history and importance of the moon to life on Earth. The message is that there might be no life on Earth, beyond the microbial, without the Moon which came from an accidental impact by another solar body into the earth, and that life evolved after the moon made weather, tides, and the rotation of the Earth possible.

The future is forecast that as the moon moves away from Earth, Earth will slow and cease to rotate, the weather system will fail, and life as we know it will perish as the earth settles into frozen or baked wastelands.

All these stages in the life of the moon, even to portraying its size in the sky in Dinosaur times, are vividly recreated which I like better than the talk -about -it -by-experts style that fills most science videos. The collision of the smaller than Earth planet into Earth was visually spectacular and gives one a "God's Eye View" of the event that created the moon, enlarged the Earth's mass, added water, and created life. The video was last shown on either public television or Discovery in spring of 2000. Science video lovers should pray this one comes back into production!

~~~

While contemporary current thinking concerning the existence of other life in the universe is that there should be millions and millions...this is one of the viewpoints that prompted me to rethink that premise.

That 'chance' meeting with another planet, that eventually became the moon, of the earth and just the right distance from the sun and the right size, makes, in my mind, the chance of recreating that scenario in other solar systems less possible than previously thought.

I still find it an interesting question to pose...the 'what if we are the only intelligent species in the universe...'


amicus...

 

[Eluard]

This is a follow-up for those who questioned some of the assertions made in my thread concerning, "What if..."


What would life on earth be like without the moon? Well, chances are, there wouldn't be any life on earth without the moon. Life – if it had started at all – would still be in the earliest stages of evolution.

Scientists use the latest computer simulations to show how an ancient rogue planet – Orpheus – collided with the earth millions of years ago, producing a sizable chunk of debris that eventually became our moon. If that collision had never occurred, we would live in a very different place. Imagine a moon-less weather report – blizzards over the Sahara, floodwaters swallowing the Pyramids, 90-degree temperatures in Antarctica. As the earth wobbles on its axis – unsecured by the moon's gravitational pull – the polar caps would grow and recede at frightening rates. And without the moon, our planet would spin much faster – meaning four-hour days and searing temperatures.

Worse yet, evidence reveals that we are in fact losing our grip on our lunar friend thanks to the ebb and flow of the oceans' tides. Experts reveal theories for salvaging the moon – including hijacking Europa from Jupiter – and demonstrate how we can prepare ourselves for our eventual life without it.

Second keyword search: discovery science if we had no moon

http://www.christinelavin.com/discuss/messages/47.html

"If We Had No Moon", August 30, 2000
Reviewer: Michael J. Zajic (see more about me) from Bethesda, MD USA

This natural science video is one of the most beautiful and exiciting of the "planetary" videos. Unfortunately, it is currently out of production and not for sale except maybe as a used video.

The science and visual technical effects and the animations are stunning and convey the history and importance of the moon to life on Earth. The message is that there might be no life on Earth, beyond the microbial, without the Moon which came from an accidental impact by another solar body into the earth, and that life evolved after the moon made weather, tides, and the rotation of the Earth possible.

The future is forecast that as the moon moves away from Earth, Earth will slow and cease to rotate, the weather system will fail, and life as we know it will perish as the earth settles into frozen or baked wastelands.

All these stages in the life of the moon, even to portraying its size in the sky in Dinosaur times, are vividly recreated which I like better than the talk -about -it -by-experts style that fills most science videos. The collision of the smaller than Earth planet into Earth was visually spectacular and gives one a "God's Eye View" of the event that created the moon, enlarged the Earth's mass, added water, and created life. The video was last shown on either public television or Discovery in spring of 2000. Science video lovers should pray this one comes back into production!

~~~

While contemporary current thinking concerning the existence of other life in the universe is that there should be millions and millions...this is one of the viewpoints that prompted me to rethink that premise.

That 'chance' meeting with another planet, that eventually became the moon, of the earth and just the right distance from the sun and the right size, makes, in my mind, the chance of recreating that scenario in other solar systems less possible than previously thought.

I still find it an interesting question to pose...the 'what if we are the only intelligent species in the universe...'


amicus...

This is very interesting — and I genuinely mean that — but it doesn't follow from these claims that life on some other planet would be dependent on that planet having a moon.

Also, unlike others, I agree with you that the question "what if we were the only sentient beings in the Universe?" is an interesting one. We have no observational evidence that would lead us to believe there is any other sentient life out there. I find that pretty amazing, given all of the a priori probabilities that people have come up with claiming that there must be some.

 

[amicus]

This is very interesting — and I genuinely mean that — but it doesn't follow from these claims that life on some other planet would be dependent on that planet having a moon.

Also, unlike others, I agree with you that the question "what if we were the only sentient beings in the Universe?" is an interesting one. We have no observational evidence that would lead us to believe there is any other sentient life out there. I find that pretty amazing, given all of the a priori probabilities that people have come up with claiming that there must be some.

~~~

Thank you for that second paragraph Eluard(by the way what does the name mean?).

Your first paragraph however...

Acknowledging that I am a bit of a 'nerd' in terms of the subject of planetary and human evolution, yes, not 'dependent' for life to exist...but..if you can get a text of the program, they ascertain that 'life' without a satellite body, would have a much more difficult time of getting started and evolving.

My only 'profession', was as a radio announcer and a newspaper reporter, so I am not a 'professional' in any of the scientific fields I comment on.

But I am an amateur with wide appreciation for those who do know and I try to relate their discoveries and theories as best I can.

It is fact that 'life', basic life, can and does occur under very stringent environmental conditions. So on one hand, life is very tenacious, on the other, very fragile.

But for life to evolve, requires a whole host of considerations. Heat and cold, for example, a planet can only be within a certain distance of its sun for life to flourish.

And, 'life as we know it' is not a caveat. At absolute zero temperature, nothing moves; at extremely high temperatures, liquids boil away and atmospheres dissipate.

Within that same temperature zone, without an atmosphere, life cannot exist, thus it takes a planet of a certain size, with an atmosphere, to nurture and sustain life of any kind.

The planet must also have an iron core and rotation and magnetic poles to create a shield against solar and cosmic radiation which is lethal to all life.

The rotational period of a planet also is functional to the existence of life, as is the tilt of the axis of the planet, things I do not fully comprehend as to what initiates that axis tilt and rotational period.

I conclude that for our solar system to have two planets capable of bearing life, Earth and Mars, to be almost unique in all the solar systems astronomers have been able to detect.

This boils down to my original premise...that the odds of life elsewhere in the universe and much smaller than originally thought...beyond that we/I, can only speculate.

Thanks again...


Amicus...

 

[drksideofthemoon]

I'd have to come up with a new user name...

 

[amicus]

[QUOTE=drksideofthemoon]I'd have to come up with a new user name...[/QUOTE]

...(?)...

(edited to add....oh damn, dark side of the moon....geez...am I slow tonight (always) sorry....yes....there was a cartoon in a Playboy Mag (yes, but I only read the articles), long ago...when mankind finally got around to see the dark side of the moon(it only presents one side to earth)....and it was a stage prop..."Act two, Scene one", that I found amusing...)


ami

 

[Eluard]

~~~

Thank you for that second paragraph Eluard(by the way what does the name mean?).

Your first paragraph however...

Acknowledging that I am a bit of a 'nerd' in terms of the subject of planetary and human evolution, yes, not 'dependent' for life to exist...but..if you can get a text of the program, they ascertain that 'life' without a satellite body, would have a much more difficult time of getting started and evolving.

My only 'profession', was as a radio announcer and a newspaper reporter, so I am not a 'professional' in any of the scientific fields I comment on.

But I am an amateur with wide appreciation for those who do know and I try to relate their discoveries and theories as best I can.

It is fact that 'life', basic life, can and does occur under very stringent environmental conditions. So on one hand, life is very tenacious, on the other, very fragile.

But for life to evolve, requires a whole host of considerations. Heat and cold, for example, a planet can only be within a certain distance of its sun for life to flourish.

And, 'life as we know it' is not a caveat. At absolute zero temperature, nothing moves; at extremely high temperatures, liquids boil away and atmospheres dissipate.

Within that same temperature zone, without an atmosphere, life cannot exist, thus it takes a planet of a certain size, with an atmosphere, to nurture and sustain life of any kind.

The planet must also have an iron core and rotation and magnetic poles to create a shield against solar and cosmic radiation which is lethal to all life.

The rotational period of a planet also is functional to the existence of life, as is the tilt of the axis of the planet, things I do not fully comprehend as to what initiates that axis tilt and rotational period.

I conclude that for our solar system to have two planets capable of bearing life, Earth and Mars, to be almost unique in all the solar systems astronomers have been able to detect.

This boils down to my original premise...that the odds of life elsewhere in the universe and much smaller than originally thought...beyond that we/I, can only speculate.

Thanks again...


Amicus...

You may well be right that the probabilities of life elsewhere have been inflated. It's a very difficult business estimating probabilities when we know of only one case where there is sentient life. People may well have been too optimistic. (The longer SETI scoures the sky and finds nothing the more likely it is that people have been too optimistic.) But this is also a reason for being very sceptical about the possibility of us going out there and terraforming any other planet. I think these two things go together to some extent. No other habitable worlds may mean no other worlds that we can make habitable.

As to the name: it's just a tribute to the pen name of a particular French poet.

 

[amicus]

[QUOTE=Eluard]You may well be right that the probabilities of life elsewhere have been inflated. It's a very difficult business estimating probabilities when we know of only one case where there is sentient life. People may well have been too optimistic. (The longer SETI scoures the sky and finds nothing the more likely it is that people have been too optimistic.) But this is also a reason for being very sceptical about the possibility of us going out there and terraforming any other planet. I think these two things go together to some extent. No other habitable worlds may mean no other worlds that we can make habitable.

As to the name: it's just a tribute to the pen name of a particular French poet. [/QUOTE]

~~~

I at one time fancied myself a poet...gads...such an admission for the abominable amicus...and should perhaps be able to fathom the pen name of that French poet, but nothing comes to mind.

How pleasant to find another SETI (Search for Extraterrestrial Intelligence...for those who don't know) addict...I get updates from the SETI website, from Mars Rovers site and from ah, what the hell the Huygens probe site, as well as NASA updates.

"... I think these two things go together to some extent. No other habitable worlds may mean no other worlds that we can make habitable..."

I hadn't thought of that...but it does rather cut both ways, does it not?

If there are few other planets suitable for life to develop and evolve naturally, then a voyage to distant stars....hmmm....would have to be directed at one prediscovered and hopefully with a 'vacant' sign hanging out....interesting.

thanks again....

amicus

(edited to add: Paul Eluard (Eugène Grindel) 20th century French Dada and Surrealist poet...)

ain't googling neat!

 

[Pure]

el it doesn't follow from these claims that life on some other planet would be dependent on that planet having a moon.

P: a further point, however, is that having a moon is not exactly a rare occurence, at least in our solar system.

further yet, who says life must on a *planet*; there is some hypotheses that one or two of Jupiter's moons might support life, iirc, Europa, which may have an ocean(s).

http://people.msoe.edu/~tritt/sf/europa*****.html

------
We have no observational evidence that would lead us to believe there is any other sentient life out there. I find that pretty amazing, given all of the a priori probabilities that people have come up with claiming that there must be some.

i'm not sure why it's amazing, given that "life" needn't be able to send signals to earth, or even *make* signals [e.g a colony of lichens] that we might detect.

it is only in the last 20 years or so, that methods of detecting planets of near stars have been invented; yet no planets yet has been able to be inspected as to the details of its surface.

as far as the numbers, in figuring my posting above, i quickly discover some very low numbers are possible: if there 10**22 stars and only one in a trillion of them have planets, thats 10*10 stars with planets. so figuring planets at 10 per, we have 10*11 planets. Supposing only one in a billion of these planets is hospitable to known forms of life, that leaves on 10**2 possible or likely bearers of life. i.e. 100. Now picture these sprinkled through the universe and you can see we are not very likely to come across one.


looking at it a little differently, within 250 light years of the earth are only 260,000 stars (2.6 * 10**5). that sample size, for 10**22 stars is
is about one ten thousandth of a trillionth of the whole.

http://www.atlasoftheuniverse.com/250lys.html

we won't be personally running into other life form any time soon.

 

[amicus]

el it doesn't follow from these claims that life on some other planet would be dependent on that planet having a moon.

P: a further point, however, is that having a moon is not exactly a rare occurence, at least in our solar system.

further yet, who says life must on a *planet*; there is some hypotheses that one or two of Jupiter's moons might support life, iirc, Europa, which may have an ocean(s).

http://people.msoe.edu/~tritt/sf/europa*****.html

------
We have no observational evidence that would lead us to believe there is any other sentient life out there. I find that pretty amazing, given all of the a priori probabilities that people have come up with claiming that there must be some.

i'm not sure why it's amazing, given that "life" needn't be able to send signals to earth, or even *make* signals [e.g a colony of lichens] that we might detect.

it is only in the last 20 years or so, that methods of detecting planets of near stars have been invented; yet no planets yet has been able to be inspected as to the details of its surface.

as far as the numbers, in figuring my posting above, i quickly discover some very low numbers are possible: if there 10**22 stars and only one in a trillion of them have planets, thats 10*10 stars with planets. so figuring planets at 10 per, we have 10*11 planets. Supposing only one in a billion of these planets is hospitable to known forms of life, that leaves on 10**2 possible or likely bearers of life. i.e. 100. Now picture these sprinkled through the universe and you can see we are not very likely to come across one.


looking at it a little differently, within 250 light years of the earth are only 260,000 stars (2.6 * 10**5). that sample size, for 10**22 stars is
is about one ten thousandth of a trillionth of the whole.

http://www.atlasoftheuniverse.com/250lys.html

we won't be personally running into other life form any time soon.

~~~

You are an able opponent, although a corrupt one as you confront each of my posts in one way or another.



P: "...a further point, however, is that having a moon is not exactly a rare occurence, at least in our solar system."

Yes, we all know a particular 'gas giant' has several dozen moons, totally irrelevant and out of context.

"...further yet, who says life must on a *planet*; there is some hypotheses that one or two of Jupiter's moons might support life, iirc, Europa, which may have an ocean(s)."

Perhaps you are too enthused about "2001, A Space Odyssey"; key words are, 'may have' an ocean(s). Oceans of what? No doubt solid at that distance from the sun. Again, irrelevant and out of context.

"i'm not sure why it's amazing, given that "life" needn't be able to send signals to earth, or even *make* signals [e.g a colony of lichens] that we might detect."

While indeed Spirit and Opportunity are searching for any sign of life, past or present on Mars, scientists are seeking signs of 'intelligent' life, anywhere in the Universe. Your usual ploy of obfuscation and diffusion of intent.

"...it is only in the last 20 years or so, that methods of detecting planets of near stars have been invented; yet no planets yet has been able to be inspected as to the details of its surface."

Clever, clever, oh how so clever you are...SETI has been in existence since 1959, nearly half a century, not looking for 'planets of near stars', but electromagnetic emanations from anywhere.

Although you may understand your convoluted math and I get your point, most will just skip on by and you lost your point.

Perhaps you don't fully comprehend the natural laws of physics and electromagnetic propagation.

Were there the vast numbers of intelligent civilizations scattered throughout this Galaxy and the Universe at large, the moment SETI opened its ears to radio waves, the predictions of the Saganites and you yourself, should have led to a myriad of signals from all parts of the Universe in numbers beyond calculation.

There were none. Not a single peep or blip.

Fifty years later, with computer enhanced searches...there are still...none...

There is no evidence of any intelligent life anywhere else in the Universe.

Fact.

That...is rather amazing and compels one to contemplate that man is perhaps unique...wouldn't that be wunnerful?


Amicus...

 

[Eluard]

We are tripping up a bit over the difference between the possibility of life and the possibility of sentient life. The trouble is that we really don't know what led humans to become smart in the way we are — so it's hard to estimate the probability of it happening somewhere else.

I remember seeing something a few years ago on nearness to supernovae being lethal to developing life. This means (if it's correct) that advanced life forms can only develop on the edges of galaxies where the chance of life being wiped out by a nearby supernova explosion are low. This would automatically rule out all but a small percentage of stars of being able to have planets that support advanced (and not even necessarily sentient) life forms.

To give some idea of how lethal these supernova explosions are, even very distant supernovae produce gamma rays that regularly "ping" the Earth at very high energies. These rays cause cancer and those who travel often on planes have a higher risk of cancer due to the increased number of gamma rays that hit them. Any interplanetary travel would have to somehow secure themselves against these gamma rays — and this severly limits the possibility of multi-generational space travel.

 

[amicus]

We are tripping up a bit over the difference between the possibility of life and the possibility of sentient life. The trouble is that we really don't know what led humans to become smart in the way we are — so it's hard to estimate the probability of it happening somewhere else.

I remember seeing something a few years ago on nearness to supernovae being lethal to developing life. This means (if it's correct) that advanced life forms can only develop on the edges of galaxies where the chance of life being wiped out by a nearby supernova explosion are low. This would automatically rule out all but a small percentage of stars of being able to have planets that support advanced (and not even necessarily sentient) life forms.

To give some idea of how lethal these supernova explosions are, even very distant supernovae produce gamma rays that regularly "ping" the Earth at very high energies. These rays cause cancer and those who travel often on planes have a higher risk of cancer due to the increased number of gamma rays that hit them. Any interplanetary travel would have to somehow secure themselves against these gamma rays — and this severly limits the possibility of multi-generational space travel.

~~~

Yep...again you expand the arena...

Some of the astronauts enroute to the moon, reported flashing lights in their eyes. Research determined they were cosmic radiation particles, gamma rays, actually passing through the eyeball and leaving a trace.

Once again, from a philosophical viewpoint...does it not seem incongruent that man can 'see' the stars, but not achieve them?

My earlier flippant remark about a malevolent God notwithstanding, I would surmise mankind would find a way to overcome such limitations and proceed regardless?



reading your post again...

"...We are tripping up a bit over the difference between the possibility of life and the possibility of sentient life. The trouble is that we really don't know what led humans to become smart in the way we are — so it's hard to estimate the probability of it happening somewhere else..."

As you most likely know, there are many different theories on how humans became, 'smart', which enabled them to become sentient, all very interesting to consider.

I draw from those theories, regardless of how...it did come about. I justify my optimism, (if I have any), that within all the permutations and combinations possible, that it did happen once and could happen again.

This both supports and questions my position...par for the course.

grins...


Thanks again...after a rather shaky beginning, a pleasure to meet your mind.

amicus....




amicus...

 

[R. Richard]

SETI has failed to find evidence of life on other planets.

Some years ago some well meaning idiots began to beam a radio-telescope signal into space to announce to the universe that 'we are here!' The military began to apply standard estimating techniques, based upon our contacts with other [terrestrial] civilizations. The military first estimated that there was a probablility of so many worlds with intelligent life in some distance of Earth. Of said worlds, a certain, lower number would receive and understand our transmission. Several of the worlds with intelligent life within some distance of Earth would want to attack/conquer Earth. At least a couple of the worlds would have the capability to attack/conquer Earth.

The 'we are here!' project was abruptly cancelled. The name of the ill fated project was then assigned to at least two later projects that had nothing to do with 'we are here!' You can't find records of the project, even on the 'Net. You have to talk to people active in the space program back when.

Be carerful of what you wish for, you may get it.

 

[amicus]

SETI has failed to find evidence of life on other planets.

Some years ago some well meaning idiots began to beam a radio-telescope signal into space to announce to the universe that 'we are here!' The military began to apply standard estimating techniques, based upon our contacts with other [terrestrial] civilizations. The military first estimated that there was a probablility of so many worlds with intelligent life in some distance of Earth. Of said worlds, a certain, lower number would receive and understand our transmission. Several of the worlds with intelligent life within some distance of Earth would want to attack/conquer Earth. At least a couple of the worlds would have the capability to attack/conquer Earth.

The 'we are here!' project was abruptly cancelled. The name of the ill fated project was then assigned to at least two later projects that had nothing to do with 'we are here!' You can't find records of the project, even on the 'Net. You have to talk to people active in the space program back when.

Be carerful of what you wish for, you may get it.

~~~

Interesting, RRichard, but I question your assumptions although not your relating the incidents.

In a NASA program concerning one of the early Mariner probes far distant from launchpad earth it was stated that the radio energy transmitted by Mariner, when it reached earth was on the order of a half a billionth of a watt.

The premise of 'Contact', the film from Carl Sagan's book, was that early radio and television transmissions continued traveling through space for dozens of years.

I don't have, off the top of my head, the formulas defining the attenuation of radio waves in space and if in fact they could travel the distance to nearby stars with enough energy left to be received.

My point is, whether it was a purposely generated signal stating: "Here we are!" or simply broadcast radiation and even communication with space probes, we are in essence announcing ourselves to the universe at large.

The latest I recall hearing is that NASA is building or has built a megawatt laser beacon for just that purpose, loudly announcing our presence.

I find it all quite fascinating.

Amicus

 

[Pure]

it is not a simple problem however to design a message for sending to the universe that says, "we are here" or "there are intelligent beings, humans, on Earth, third planet from [xxx] large star."

supposing we consider the signal, at some frequency, is like a beeping. what beeps would you have to hear to know an intelligent being was sending them? OR from the other side, what would they have to hear.

in the past, some suggested regularly spaced beeps, over particular periods. but it was found some stars send out such signals (perhaps little guys are inside, however).

 

[amicus]

[QUOTE=Pure]it is not a simple problem however to design a message for sending to the universe that says, "we are here" or "there are intelligent beings, humans, on Earth, third planet from [xxx] large star."

supposing we consider the signal, at some frequency, is like a beeping. what beeps would you have to hear to know an intelligent being was sending them? OR from the other side, what would they have to hear.

in the past, some suggested regularly spaced beeps, over particular periods. but it was found some stars send out such signals (perhaps little guys are inside, however).[/QUOTE]

~~~

Perhaps if you read Sagan's book you would find the difficulty has been addressed.

amicus...

 

[Guest]

No moon?

Pink Floyd would have to rename a very decent album.

 

[R. Richard]

it is not a simple problem however to design a message for sending to the universe that says, "we are here" or "there are intelligent beings, humans, on Earth, third planet from [xxx] large star."

supposing we consider the signal, at some frequency, is like a beeping. what beeps would you have to hear to know an intelligent being was sending them? OR from the other side, what would they have to hear.

in the past, some suggested regularly spaced beeps, over particular periods. but it was found some stars send out such signals (perhaps little guys are inside, however).

The design of a 'we are here' message is not too difficult. A series of 'beeps' can simply be a number series, something that would be recognizable to any intelligent culture. Something like a Fibonacci series, repeated over and over, is too structured to be accidental.

It is also practical to send 'pictures,' constructed of two different kinds of 'beeps.' The beeps are basically 'one and zero.' The one dots, separated by the zero dots, paint a picture. The key is that the total number of beeps needs to be a 'near prime number,' that is the product of two prime numbers. The intelligent receiver of such a message observes that arranging the beeps in an M by N [or N by M] matrix paints a picture.

 

[Eluard]

Yep...again you expand the arena...

Some of the astronauts enroute to the moon, reported flashing lights in their eyes. Research determined they were cosmic radiation particles, gamma rays, actually passing through the eyeball and leaving a trace.

Yes, I'd read something on that — and none of them said anything while they were actually up there.

reading your post again...

"...We are tripping up a bit over the difference between the possibility of life and the possibility of sentient life. The trouble is that we really don't know what led humans to become smart in the way we are — so it's hard to estimate the probability of it happening somewhere else..."

As you most likely know, there are many different theories on how humans became, 'smart', which enabled them to become sentient, all very interesting to consider.

I draw from those theories, regardless of how...it did come about. I justify my optimism, (if I have any), that within all the permutations and combinations possible, that it did happen once and could happen again.

This both supports and questions my position...par for the course.

grins...


Thanks again...after a rather shaky beginning, a pleasure to meet your mind.

amicus....

Yes, likewise. Personally though, I'm much more pessimistic than you are about a) anything being out there, and b) us ever getting out there. We are in a race against stupidity and stupidity is proving to be faster than we'd imagined. But then I'm a curmudgeon these days.

Shanglan seems to be off with a mare somewhere — either that or he's composing a really long reply!

 

[R. Richard]

Attenuation is a problem, but noise is a far greater problem. By the time radio or TV signals travel a long way through space, they are very weak and full of noise. The idea that someone several light years away could receive radio or TV signals and filter out the noise is of very, very low probability.

A radio telescope type device can project a focused beam and/or a powerful broad beam. The beam is not coded with information, as a radio or TV beam would be, but simply a sequence of beeps. The pattern is in the beeps, not in the signal itself.

If some idiot is announcing to the universe at large, "We of Earth are here, we come in peace!" then that idiot is signing the rest of the population of Earth up for a suicide mission. I didn't sign up for a suicide mission and, even if I were willing to sign up, I doubt that the idiots could afford my rates. [The "we come in peace!" is, I believe a legally required part of such message.] [I have signed up for several 'suicide missions' in my time. However, I knew enough about the risks that the mission did have some aspects of a suicide mission, but for other people, not for me.]

 

[amicus]

Attenuation is a problem, but noise is a far greater problem. By the time radio or TV signals travel a long way through space, they are very weak and full of noise. The idea that someone several light years away could receive radio or TV signals and filter out the noise is of very, very low probability.

A radio telescope type device can project a focused beam and/or a powerful broad beam. The beam is not coded with information, as a radio or TV beam would be, but simply a sequence of beeps. The pattern is in the beeps, not in the signal itself.

If some idiot is announcing to the universe at large, "We of Earth are here, we come in peace!" then that idiot is signing the rest of the population of Earth up for a suicide mission. I didn't sign up for a suicide mission and, even if I were willing to sign up, I doubt that the idiots could afford my rates. [The "we come in peace!" is, I believe a legally required part of such message.] [I have signed up for several 'suicide missions' in my time. However, I knew enough about the risks that the mission did have some aspects of a suicide mission, but for other people, not for me.]

~~~

Signal to noise ratio's have been a concern since I was constructing transmitters and receivers with vacuum tubes.

Frequency used also has a bearing as some noise is generated by cosmic activity on a certain band and not others. I see your point, I just don't agree with it. I think the event of discovering another intelligent species in the Universe would be a marvelous occurrence.

Based on past human hostilities towards each other, I again understand your viewpoint but I maintain that man's insatiable desire to cross oceans and space is not dependent on the fear of discovering hostile natives.

amicus...

 

[R. Richard]

Signal to noise ratio's have been a concern since I was constructing transmitters and receivers with vacuum tubes.

Frequency used also has a bearing as some noise is generated by cosmic activity on a certain band and not others. I see your point, I just don't agree with it. I think the event of discovering another intelligent species in the Universe would be a marvelous occurrence.

Based on past human hostilities towards each other, I again understand your viewpoint but I maintain that man's insatiable desire to cross oceans and space is not dependent on the fear of discovering hostile natives.

amicus...

If you cross the ocean in a European [or Chinese] iron age ship that is too large for the stone age natives to overwhelm, you need not fear the natives too much. What if the natives are not stone age and prove to have submarines and nasty tempers?

Most of the noise in the universe is generated by stars [and apparently black holes!] The noise generated then encounters other objects and is rebroadcast on other frequencies. Yes, it is possible to select frequencies that would have some approach to a reasonable minimum of noise. The question then becomes, is there anyone listening on said frequencies?

It would be nice to find an advanced, peaceful race [or whatever] of aliens. What is the aliens were akin to the Arab slave raiders who 'discovered' black African tribes? Worse yet, what if the aliens didn't want slaves, just brains and spinal columns that they could use as device controllers?

 

[Zeb_Carter]

I just have one question...

Why would sentient life have to look like us?

I mean why would sentient life have to be carbon based? With all the other elements in the universe, those we know of and those yet to be discovered, why would other sentient life have to have a moon orbiting their planet? Why would they need water, maybe liquid sulfur is their drink of choice?

True, life on Earth is carbon based but who's to say on Alpha-Centuri 4 they may be silicon based or strontium based. Who's to say?

 

[amicus]

I just have one question...

Why would sentient life have to look like us?

I mean why would sentient life have to be carbon based? With all the other elements in the universe, those we know of and those yet to be discovered, why would other sentient life have to have a moon orbiting their planet? Why would they need water, maybe liquid sulfur is their drink of choice?

True, life on Earth is carbon based but who's to say on Alpha-Centuri 4 they may be silicon based or strontium based. Who's to say?

~~~

Before it slips my mind Shanglan asked about Mars, one of the programs is replaying tonight, Science Channel, Space Station and Beyond....

As far as my understanding goes, other sentient life need not look like us. Again, as I understand it, physical size and appearance would depend on the environment they evolved in.

I cannot give a scientific answer on carbon based silicon based life. I have read many speculative fiction and non fiction treatises on many possible forms of life and evolution but none is definitive in my mind, perhaps others can better answer that.

In our little patch of the Milky Way, there seems agreement that water, the universal solvent is an essential necessity for the development of any life form, since I cannot prove that, I offer it only as what I have read.

Many science fiction stories feature life forms off all kinds, crystalline structures, pure energy, silicone based, the imagination has no limits but how closely they mesh with known science I can but speculate.

I find the entire concept of ET's absolutely fascinating to muse about.

amicus...

 

[BlackShanglan]

Amicus, this is interesting and delightful reading! Thank you very much for the thread. It's much appreciated.

The relationships between our own forms of life and the moon's influence on our environment are fascinating. However, the humor part of my brain can't help throwing up an image of a couple of Far Side-style alien scientists looking at a diagram of a planet with a moon and declaring that no intelligent life could ever evolve in such a constantly changing and unsettled environment. *laugh* Still, they raise good questions. Intelligent life particularly seems to need such a delicate balance to evolve - hospitable enough climate that it's not wiped out at any stage from microbe on up, and yet hostile enough that it needs to evolve and genetically selects mostly the most intelligent specimens generation after generation.

It reminds me a science fiction story / speculation I read ages ago, called, I think, "Small Mouth, Bad Taste." The central character posits that perhaps humans owed much of our evolutionary success to two key factors: tasting bad and having a mouth that is relatively small in relationship to the rest of our bodies. The author's theory was that we were continually pushed toward tool use because it was more difficult for an animal of a human's weight to consume sufficient food through a little narrow mouth. I think he might have been playing cart and horse games, but it was still an intriguing thought. Looking at my cat, I often think that there's a straightforward answer to why there are no feline intelligent species: they're too good at what they do! With natural abilities like that, who needs tools?

Perhaps we do owe something to moon, and not just because it makes some parts of our lives more clement. Perhaps the seasonal changes in weather, water, and food created conditions that helped to select for and encourage intelligence?

Shanglan

 

[BlackShanglan]

I remember seeing something a few years ago on nearness to supernovae being lethal to developing life. This means (if it's correct) that advanced life forms can only develop on the edges of galaxies where the chance of life being wiped out by a nearby supernova explosion are low. This would automatically rule out all but a small percentage of stars of being able to have planets that support advanced (and not even necessarily sentient) life forms.

To give some idea of how lethal these supernova explosions are, even very distant supernovae produce gamma rays that regularly "ping" the Earth at very high energies. These rays cause cancer and those who travel often on planes have a higher risk of cancer due to the increased number of gamma rays that hit them. Any interplanetary travel would have to somehow secure themselves against these gamma rays — and this severly limits the possibility of multi-generational space travel.

Fascinating! Do think it's possible that if a life form evolved on the near border of such an area, it might be able to develop some sort of defense mechanism? I find extremeophiles fascinating ... I think that one of my favorite parts about science fiction is asking "If I had these conditions, what would life look like if it evolved there?"