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How many of you have ever thought this?

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#1 caheaton

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Posted 16 July 2013 - 04:56 PM

During my recent camping trip, following spending close to an hour on M51, I decided to slew to a nearby random galaxy (chosen from the Pocket Sky Atlas) to see what I could find. I ended up choosing NGC3877. I was pleasantly surprised, the galaxy was fairly bright with an attractive shape indicating it was tilted close to edge on (aka Andromeda) with a hint of mottling. I then thought to myself, "attractive, but not as stunning as the more famous Messiers that abound in the area, but yet to someone this is home! :grin: ".

And maybe...just maybe, someone in 3877 was looking at us and thinking the same thing...
Craig

#2 StrangeDejavu

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Posted 16 July 2013 - 06:57 PM

Every time I find a galaxy in the eyepiece, this goes through my head. It really gives that gray smudge some depth. :waytogo:

#3 CelestronDaddy

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Posted 16 July 2013 - 08:47 PM

Makes you wonder doesn't it! :grin:

#4 ggalilei

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Posted 16 July 2013 - 10:21 PM

Me too, actually, but the thought is tempered by the realization that I'd be looking at someone looking this way millions of years ago. Or I'll be "seen" by somene looking this way some million years from now.

#5 Rich (RLTYS)

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Posted 17 July 2013 - 07:22 AM

That same thought goes thru my head whenever I look up at a starry sky.

Rich (RLTYS)

#6 Jon Isaacs

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Posted 17 July 2013 - 09:05 AM

And maybe...just maybe, someone in 3877 was looking at us and thinking the same thing...



Indeed, it's hard to avoid thinking that someone somewhere is looking back.

And since if someone on NGC3877 is actually looking at me while I am observing, it will be approximately 50 million years in the future, I make sure I am appropriately dressed so as not to offend their sensibilities... :)

Jon

#7 FJA

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Posted 17 July 2013 - 09:22 AM

For me, part of the appeal of observing is looking at deep sky objects, especially galaxies, and wondering what other life they harbour and what form it might take.

#8 Tony Flanders

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Posted 17 July 2013 - 11:38 AM

For whatever reason, I never think about extraterrestrial life when I'm stargazing. I guess it's partly because I'm somewhat skeptical by nature. Intellectually, I think it's likely that there is life off of Earth -- I would happily give ten-to-one odds if there was some omniscient being we could consult afterward to settle the bet. But my hunch is that there won't be compelling evidence of life off of Earth before I die, which makes the bet distinctly less interesting.

As to multicellular life or intelligence, that's just too hard for my brain to extrapolate. I really don't have a gut feeling about those -- wouldn't be surprised if intelligent life exists off of Earth, wouldn't be surprised if we're unique in the universe.

#9 uniondrone

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Posted 17 July 2013 - 12:32 PM

As to multicellular life or intelligence, that's just too hard for my brain to extrapolate. I really don't have a gut feeling about those -- wouldn't be surprised if intelligent life exists off of Earth, wouldn't be surprised if we're unique in the universe.


I find it interesting that you chose to say multicellular life. There has been life on Earth for about 3.6 billion years, but multicellular life for only about 1 billion years. To me at least, that seems to say something about the relative probability (or improbability) of multicellular organisms compared to simpler forms. It could very well be true that this is one of the great hurdles that extraterrestrial life would have to clear, and that a large percentage of worlds having conditions suitable for life may never get beyond this point.

#10 aatt

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Posted 17 July 2013 - 02:04 PM

I often think about this when observing. I think that with 900+exoplanets having been discovered and with 3 likely candidates for conditions amenable to life in this solar system the likelihood of life elsewhere is very large.The basic building blocks of life have been shown to be common. As long as there is stability on a planet or moon-which life can play a role in maintaining-the possibility of development happens. The key event is probably consuming another organism which could then lead to symbiosis. The mitochondrial symbiotic event here was critical to multicellularity, but that could only happen after our atmosphere was oxygenated by photosynthesizers. I think that this type of thing is common-we see various forms of cooperative living happening here on Earth right now. It is probably a universal phenomenon. As to intelligent life existing just ask a crow or a dolphin. As to technological civilizations, I think that surviving technology is the key hurdle to overcome. Many civilizations have probably arisen, but have exterminated themselves from their own "intelligence". We will have to wait and see for ourselves whether we will survive this system we have created. It could happen-I hope so....the signs are not looking good on many fronts.I often wonder about someone looking back and if their future generations have survived to tell the tale.

#11 Tony Flanders

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Posted 17 July 2013 - 02:52 PM

With 3 likely candidates for conditions amenable to life in this solar system the likelihood of life elsewhere is very large.


Frankly, we don't know what's amenable to life. We have exactly one example of a planet that's home to life, so we naturally take that as the prototype. But for all we know Earth is actually relatively hostile to life, and far different planets would be more hospitable.

All life on Earth has fundamentally similar biochemistry, which may mean that this is the only possible kind, or the best possible kind, or it may be pure accident. We don't even know if something akin to life could exist based on mechanics rather than chemistry.

Above all, nobody yet has come up with a halfway plausible scenario of how life can evolve from non-life. Every form of life that we currently know or can even imagine is far too complex to occur by random assemblage of molecules. Which raises the serious possibility that life is immensely improbable, and has in fact evolved exactly once in the observable universe.

The current zeitgeist finds this idea unpalatable, but it's as consistent with the evidence as the idea that life is widespread.

#12 caheaton

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Posted 17 July 2013 - 03:23 PM

One thing that strikes me is that in the search for life, temperate temperatures and water (or other liquid) seem to be a prerequisite. It's only a requirement for life as we know it...life evolved on Earth to suit the planet's conditions. Whose to say that life won't evolve on another world to suit its environment...and such life forms may well considerable Earth to be a planet that's inhospitable to life. This idea seems to be born out by the relatively recent discovery of extremophiles living in the most inhospitable biomes Earth has to offer.

As to complex life, I think Sagan said it best. "These are some of the things that molecules do given four billion years of evolution." And given the universe's age, some molecules may have had much longer than that!

#13 stevecoe

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Posted 17 July 2013 - 03:56 PM

Tony, Faith, et al;

I get this in my head when viewing the Milky Way. I will take a break, have a snack and view that fasciating glow and consider life and everything. Are we the equivalent to a BD number in an alien catalog? Do they have a Kepler satellite to tell them when Jupiter and later Earth crosses the Sun? Are they whizzing around at 100 times the speed of light, or are they just crawling out of the caves on their planet? It certainly would be amazing to know.

Clear skies;
Steve Coe

#14 uniondrone

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Posted 17 July 2013 - 04:20 PM

Above all, nobody yet has come up with a halfway plausible scenario of how life can evolve from non-life. Every form of life that we currently know or can even imagine is far too complex to occur by random assemblage of molecules. Which raises the serious possibility that life is immensely improbable, and has in fact evolved exactly once in the observable universe.


I've read some scenarios that seemed at least halfway plausible. :grin:

Naturally occurring surfactant molecules of non-biological origin can readily self-assemble into liposome structures that are similar to cell walls. It's not too terrible of a stretch to think that the hydrophillic interior of a liposome could attract aqueous metal ions that could help mediate or catalyze the formation of amino acids or nucleic acids into polymeric chains. If one of these polymeric chains (i.e. proteins, DNA, or RNA) happens to stumble onto a configuration that is self-replicating, then the rest is history (and evolution).

#15 aatt

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Posted 17 July 2013 - 07:12 PM

There are many plausible scenarios-but the idea/phenomenon of self-assembly which readily happens in viruses, proteins and with oils (bubbles)is an important part of the theories on the origin of life.Basic amino acids from hydrogen cyanide,RNA's that splice themselves, sugars from formaldehyde, the first protocells/oil bubbles with RNA caught inside naturally growing and outcompeting other non-RNA containing bubbles due to osmosis and others ideas all make sense at a certain level. There are many ideas and of course none can explain everything and nothing has been duplicated in the lab (with the exception of some intriguing work by Theodore Szostak et al). All it takes is for random chance to get one cell and the rest is history-although it beggars belief that something as complex as even simple bacterial metabolism could happen randomly.There are some common features to all metabolism and all complexity arises from simpler units put together into larger more numerous arrays or order.Consider RNA and nucleotides-RNA splices itself, moves stuff around, codes for/makes protein, the nucleotide itself can function as an information unit, an energy source and cellular signaling. They have natural affinities for amino acids, for each other and phosphates. This basic building block has a multifunctional potential. It is possible-after all,we are here.Back in the day in the primordial oceans the number of molecules must have been astronomical-pardon the pun-that number and random chance probably won out.Those first cells must have been fabulously successful floating in what amounted to a nutrient broth.Anywhere else where you have water and the essential elements of life and stability, you could have life. I think that life is probably very abundant in simpler forms, less so in multicellular forms and rarely in a technological/savvy way.So as you gaze at a galaxy with its' billions of stars and even more planets and moons, there probably is something looking back at you and wondering-be it past or present. Right now we will probably never know that, but it is still cool to think about.

#16 Usquebae

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Posted 17 July 2013 - 08:08 PM

[tip-toeing in from the philosophy forum, if that is permissible...]

Tony's comments strike me as pessimistic, and I don't frankly see the sense in arguing that a less interesting (or fun, exciting, etc.) hypothesis is as probable as one that inspires wonderment. You might win the lottery tomorrow; you might get hit by a bus. Which would you rather dream about?

Okay, bad analogy, but I expect you get my meaning. Whatever the likelihood, I plan to do some ice fishing on Enceladus before I die, and everyone's invited. Even Mr. Flanders. :poke: And if there ain't no fish in that sea, we'll stock it!

:fishing:

#17 DavidNealMinnick

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Posted 17 July 2013 - 10:07 PM

I'm pretty much with Tony on this topic. I'll believe other life is out there when I see the unmistakable evidence. The universe is an absolute wonder, no question, but I don't wonder about life elsewhere.

#18 azure1961p

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Posted 17 July 2013 - 10:11 PM

I have zero doubt that there is complex intelligent life out there somewhere. The question to my mind is - how common? I think Sagan was awfully optimistic with SETI though I am truly grateful for it. I would strongly guess all galaxies (virtually) contain some life intelligent life . The notion however that I can gaze at a Milkyway cluster and believe someone's looking back is unrealistic. I think thats a little too too rosy for now. That we are actually nothing special out here orbiting a nothing special star however seems to play well into the belief or theory of complex life elsewhere. Its just a matter of frequency that makes me wonder.



What's astounding to me is the vast potential for a sentient being beyond human conception in thought and reason. The sheer expanse of the universe would seem to be fertile ground for such a wildly advanced being.
I strongly believe we can't possibly the tip of the pyramid on a cosmic scale.
Pete

#19 Tony Flanders

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Posted 18 July 2013 - 07:00 AM

Tony's comments strike me as pessimistic, and I don't frankly see the sense in arguing that a less interesting (or fun, exciting, etc.) hypothesis is as probable as one that inspires wonderment.


Odd! I don't see my remarks as pessimistic, and I don't see that the hypothesis that life on Earth is unique is any less interesting, fun, or exciting than the hypothesis that life is widespread. One might even argue the opposite.

Whatever the likelihood, I plan to do some ice fishing on Enceladus before I die, and everyone's invited.


Hmm, that's another matter. Call it pessimism or realism, but I'd be willing to bet quite a lot that there isn't life on Enceladus. And I'm quite willing to bet that no human being will set foot on a moon of Saturn in any of our lifetimes.

#20 caheaton

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Posted 18 July 2013 - 08:15 AM

Along the lines of how life could take other forms that we may not even recognize as life, has anyone read the book by Fred Hoyle "The Black Cloud"? I read it as a young teenager and portions of the book still stick in my mind quite vividly. The premise is that an intelligent life form is in the shape of a dark molecular cloud. The cloud is eclipsing the sun, causing havoc on Earth. When people on Earth eventually make communication with the cloud, the cloud is surprised to discover that there are life forms on the planet, and states that it had never considered the possibility of intelligent life existing on planets! :grin:

It's a good read...one that I'll have to read again soon now that I'm remembering it!

#21 Tony Flanders

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Posted 18 July 2013 - 08:47 AM

Along the lines of how life could take other forms that we may not even recognize as life, has anyone read the book by Fred Hoyle "The Black Cloud?"


Yes, The Black Cloud is a wonderful book. And Hoyle has a wonderful explanation for how life came to exist -- it didn't! As the primary advocate for the Steady State theory, Hoyle believed that the universe had always existed -- that time stretches infinitely in both directions. So, the Black Cloud says or implies, life has always existed; there's no need to explain how it started.

When people on Earth eventually make communication with the cloud, the cloud is surprised to discover that there are life forms on the planet, and states that it had never considered the possibility of intelligent life existing on planets!


No, the Cloud says that intelligent life on planets is relatively rare -- but obviously not all that exotic.

#22 Usquebae

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Posted 18 July 2013 - 09:03 AM

"The Black Cloud" is mentioned in a lecture course I'm listening to on Origins of Life, which discusses (among many other topics) how we don't have a consensus definition for what "life" is. Some might describe any kind of self-regulating system as a form of life - like sand dunes reorganizing to more efficiently pass energy (in the form of wind) through the system. The lines between biology, chemistry, and physics may not be broad, or may not truly exist at all. In the search for ET "life," we're really just trying to recognize Earth-like circumstances elsewhere.

Tony - points taken, and I will not bet you on my making it to Saturn, nor on my finding native trout when I get there. But know that I am perfectly realistic - I plan to bring a sandwich with me, in case I get skunked.

I think I had too much Shel Silverstein read to me as a child... :rainbow:

Listen to the MUSTN'TS, child,
Listen to the DON'TS,
Listen to the SHOULDN'TS
The IMPOSSIBLES, the WON'TS
Listen to the NEVER HAVES
Then listen close to me--
Anything can happen, child,
ANYTHING can be.


-S. Silverstein

#23 IVM

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Posted 18 July 2013 - 09:14 AM

I do think what the OP and the others in the same vein think when looking at a galaxy. Used to think this literally every time; now, some hundreds of galaxies later, the thought does not get worded as compulsively any more, but it is still in my mind.

The question here is whether stargazing with telescopes is common enough in the universe. I am not an expert (the science of astrobiology really took off since I last read something systematically about this, and I am afraid that the development of the science of technology and society evolution may be the one actually limiting our understanding here), but my guess is that it is common enough that it is reasonable to entertain this thought when looking at a spiral galaxy, such as NGC 3877. At least if we require only one being (at a time) looking back.

Remember, they must have clear skies at least as often as we have in the Appalachia, in addition to being technological, etc.

Beyond that, I like to imagine the perspective we present to them. For example, someone viewing from NGC 3877, far from our Galactic plane, will likely see us as comparatively more face-on than we see them.

EDIT: Incidentally, idle stargazing with large telescopes, which I believe is implied here, may be one of the most sublime and fragile manifestations in a technological civilization. So if life is common and civilization is common, it can still be rare.

#24 caheaton

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Posted 18 July 2013 - 10:15 AM

Thanks for the correction, Tony. I was able to track down a quote from the book and you're correct:

"[it] is most unusual to find animals with technical skills inhabiting planets, which are in the nature of extreme outposts of life... Living on the surface of a solid body, you are exposed to a strong gravitational force. This greatly limits the size to which your animals can grow and hence limits the scope of your neurological activity..."

Oh well...I was a kid then and it's been at least 35 years since I read it! :o

Good point made by IVM about whether or not other species would stargaze as a hobby. I would like to think they would, but then again there's a quote in the program Torchwood where Jack (a man who is immortal due to an accident and has traveled the universe through time and space) makes the observation that humans are the only species in the entire universe that goes camping! :lol:
("No other race in the universe goes camping. Celebrate your uniqueness!")






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