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Old 06-13-2019, 10:31 AM
 
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Quote:
Originally Posted by rstevens62 View Post
If its truly just us, on this planet, in the entire universe, WOW, that is scary. Probably the most frightening scenario actually.
Why scary? If anything, it should allow a greater appreciation of Earth and our place in the universe. No one is saying that there is no life, even intelligent life elsewhere in the universe or even in our home galaxy. The article was pointing out that life, as we know it, may be pretty rare. However, as I was trying to point out, we have a very minute sample of planets in habitable zones of their home stars. Most, not all, are close to the edge of the zone, meaning too close or too far in the zone from the star, the planet's atmosphere would either be blown away by solar winds or freeze. Not very Earth-like.

If that's the case, and we don't know either way, how is that a frightening scenario? It doesn't mean that we'll be forever stuck on the Earth, unable to gradually explore other planetary systems. We're planning to return to the Moon and planning to send people to Mars. Future scenarios of those bodies is that people will eventually live or work there. It is conceivable that we may ultimately not settle on planets of other stars and instead live in large city-sized (or larger) space habitats and descend to planets for resources as needed.

Another non-frightening view is that there might be others elsewhere in the galaxy and the universe, and that we might be among some of the first intelligent life forms to emerge. This might be the time in the evolution of the universe that life has begun to appear here and there. Everything has to start somewhere.

If we are relatively alone or rare, such scenarios are not anything to be paranoid about. If anything, we should be glad we are here in the universe at this point in time, which is the Stelliferous Era of stars and light. We're a part of the universe. As such, we are also the part that enables the universe to look and contemplate itself, and explore itself.
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Old 06-13-2019, 11:47 AM
 
5,091 posts, read 8,067,944 times
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Quote:
Originally Posted by Mark S. View Post
But I don't share ^those assumptions. It's possible sure. But just because life evolved in a certain way on our little pond in the cosmos doesn't necessarily mean that it always evolves that way. We just don't know and don't have sufficient data to prove it either way.

To add to the fun: What do we mean exactly by "Life?" Is it possible it's out there and we just aren't able to recognize it? Perhaps our definition is too narrow? See:
Exactly. We don't know either way.

I suspect that if there is life elsewhere, then the most common form would be microbial. Less common would be multicellular, and rare would be intelligent life, and the most rare - intelligent life capable of space travel. To try to determine what actually defines life is very complex. We only have one example, namely the diversity of life here on Earth. So we know there is life on Earth. It is pointless to speculate if our definition is too narrow. I mean, can we say rocks are a form of life? Probably not. But still, many of the minerals contained in rocks are contained and required by plants, people and other kinds of animals. Are gasses a living entity? I don't think so, but life needs certain gasses to survive. What differentiates life from rocks is that we have stuff like DNA and RNA that are "programmed" to replicate in ways that rocks and gas can't. Something to think about is that hydrocarbons and proteins by themselves aren't intelligent forms of life. Even an atom is not intelligent by itself by itself. Combine an enormous number of them together in just the right way and you can have something that's alive.

Hydrocarbons and proteins are simply forms of chemical properties that under some remarkable conditions and circumstances joined together and changed into something different. Those strands of RNA and DNA which ultimately became protectively covered to form a cell. After a few billion years these things became more specialized and evolved into us and other forms of life on the planet. What we know so far, is that hydrocarbons, a precursor of life (but is not itself life), are pretty common in the universe. We also know that water is pretty common in the universe, even though water in and of itself is not a living entity. When considering all the steps it took for life to arise and evolve here on Earth, the odds become staggering in terms that things worked out in exactly the way as it has. It's mind-boggling to consider that it happened at all. The odds of it happening numerous times elsewhere, is even more unlikely. Don't get me wrong. I'm not saying impossible though.

Until there is evidence that life, not to mention intelligent life, has indeed emerged elsewhere, there is no way to be sure. Even if we find microbial life under the surface of Mars, that still doesn't answer the question. Microbial life (bacteria, etc) could have emerged on Mars and arrived on Earth from an asteroid collision on the red planet, or even the other way around. At this point in time, we're still searching the solar system. We haven't yet gone out to explore other planetary systems. Until then, we're left in the dark with a lack of definitive answers. My bet would be if we find life elsewhere, to would have evolved in a similar manner as life on Earth. That said, the evolution of life elsewhere could be very different looking. But there'd likely be some similarities in terms of origins. It's likely that hydrocarbons would've formed proteins which in turn combined to make stuff similar to RNA and DNA to begin replicating itself.

We don't know every single step that took place for life to form on Earth. We have a good enough idea that we think we're on the right path though. If there is life that does not fit our view of it, then what other alternative views are there? What other conditions could there be?

I haven't yet watched the videos, but I will. Thanks in advance.
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Old 06-13-2019, 10:39 PM
 
10,569 posts, read 2,702,109 times
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Quote:
Originally Posted by NightBazaar View Post
Why scary? If anything, it should allow a greater appreciation of Earth and our place in the universe. No one is saying that there is no life, even intelligent life elsewhere in the universe or even in our home galaxy. The article was pointing out that life, as we know it, may be pretty rare. However, as I was trying to point out, we have a very minute sample of planets in habitable zones of their home stars. Most, not all, are close to the edge of the zone, meaning too close or too far in the zone from the star, the planet's atmosphere would either be blown away by solar winds or freeze. Not very Earth-like.

If that's the case, and we don't know either way, how is that a frightening scenario? It doesn't mean that we'll be forever stuck on the Earth, unable to gradually explore other planetary systems. We're planning to return to the Moon and planning to send people to Mars. Future scenarios of those bodies is that people will eventually live or work there. It is conceivable that we may ultimately not settle on planets of other stars and instead live in large city-sized (or larger) space habitats and descend to planets for resources as needed.

Another non-frightening view is that there might be others elsewhere in the galaxy and the universe, and that we might be among some of the first intelligent life forms to emerge. This might be the time in the evolution of the universe that life has begun to appear here and there. Everything has to start somewhere.

If we are relatively alone or rare, such scenarios are not anything to be paranoid about. If anything, we should be glad we are here in the universe at this point in time, which is the Stelliferous Era of stars and light. We're a part of the universe. As such, we are also the part that enables the universe to look and contemplate itself, and explore itself.
I see your point, but the way I see it, if we are pretty much all alone in the space we are aware of...that is just eerie, sort of in a 'twilight zone' kind of way if that makes any sense! (all these planets out there, but totally void of any life!)
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Old 06-14-2019, 07:03 AM
 
Location: Falls Church, Fairfax County
4,854 posts, read 2,907,438 times
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Quote:
Originally Posted by rstevens62 View Post
I see your point, but the way I see it, if we are pretty much all alone in the space we are aware of...that is just eerie, sort of in a 'twilight zone' kind of way if that makes any sense! (all these planets out there, but totally void of any life!)
Nobody is saying that there is not life out there. Nobody is saying that there is not intelligent life out there. What people are saying is that we have no proof of intelligent alien life anywhere near us.



There are a lot of reasons that the Universe may be teaming with life but not no intelligent, extraterrestrial, life here now. I've read a fair number of your posts and it seems your strategy is to set up a strawman to defeat and declare that you are right. People really in search of information and knowledge do not have to resort to dishonesty.
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Old 06-14-2019, 10:14 AM
 
Location: Greenville, SC
4,643 posts, read 3,701,111 times
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Quote:
Originally Posted by Old Guard View Post
Nobody is saying that there is not life out there. Nobody is saying that there is not intelligent life out there. What people are saying is that we have no proof of intelligent alien life anywhere near us.

There are a lot of reasons that the Universe may be teaming with life but not no intelligent, extraterrestrial, life here now. ...
A year or so ago, one of the posts in this forum prompted me to have a look at the Drake Equation and do a bit of back-of-the-envelope calculation of my own based on what we know now. The Drake Equation was formulated in 1961, and everything was a guess then. We now know more about the mechanisms behind evolution, sociobiology, the evolution of intelligence, and the sort of things that are likely to take out a civilizations. We also have a better idea of the number of exoplanets within a couple of hundred light years of Earth, and which potentially could be habitable by carbon-based life (we also know why life is carbon-based and why silicon is a bad substitute for carbon - even if there is life on Titan that uses liquid hydrocarbons rather than water as a solvent, it would still be carbon based. That's why search for life elsewhere in the solar system is important: if we're it or it turns out all life in our system is related due to panspermia, that tells us that the development of life from non-life may be relatively rare; if it turns out that life developed independently on multiple planets or moons, that says the development of life from non-life may be relatively common.

Other important factors to consider are: assuming life evolves everywhere as it does on Earth and the development of intelligence is inevitable, how many planets within a couple of hundred light years are likely to have intelligent life? How many of these intelligent species have a comparable level of tech to ours (and how likely it is that that species will survive long enough to develop interstellar travel)? Porpoises, elephants, and crows may be as intelligent as we are (though I personally doubt it) - where are the satellites they've launched? How about Neanderthals - where are their technological achievements beyond stone instruments, decorations, art, and perhaps musical instruments? We know now that there are a lot of threats to long-term survival of a technological civilization (the Great Filter), including the following (most of which we didn't fully understand until a few decades ago):
  • Supervolcano eruption - like Yellowstone
  • Extended period of volcanism like those that created the Deccan Traps
  • Climate change, man-made or natural
  • Another ice age due to solar changes or passage through galactic dust clouds
  • Major asteroid or comet impact
  • Pathogen mutation natural or man-made - unstoppable killer bug
  • Massive crop failure due to pathogen + lack of genetic diversity
  • Ecosystem instabilities due to reduced diversity (extinctions)
  • Massive solar flare like the one in 1850
  • Gamma ray burst from a nearby star
  • Nearby supernova
  • Oort cloud disruption by unseen solar companion raining comets on us
  • Nuclear war
  • Unforeseen effects of nanotechnology or artificial intelligence
What we *do* know is that homo sapiens and our close relatives have been around for a few million years - and attained the ability to leave earth orbit a few decades ago. Do the math.

We can imagine whatever we want about science we don't know about -- like faster than light travel and subspace communications - but that's fantasy. And I get the feeling that a lot of people here don't have a grasp on exactly how HUGE the galaxy is, or the distances involved.

My back-of-the-envelope calculations based on considerations including the above tell me that it's highly unlikely there is another species more technologically advanced than we are within a few hundred light years. If there are interstellar travelers out there a thousand light years away, they don't know we're here - or if they do, they're seeing the Earth as it was in the year 1019.
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Old 06-14-2019, 01:38 PM
 
Location: Maine
16,494 posts, read 20,763,941 times
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^
All true, but look at it from the other end of the telescope.

Given our planet's history, it's a minor miracle we're here at all with all the mass extinctions, Ice Ages, pandemic diseases, volcanic eruptions, Ice Ages, droughts, famines, etc. our species had to survive on its way to civilization.

What if another planet didn't go through all that? It's possible they achieved a higher civilization hundreds, thousands, or even millions of years prior to us. Other civilizations might not be hundreds of years ahead of ours in terms of technology, but millions of years past us.

And if we're talking about a truly Interstellar species, they would have had to have found a way to travel beyond simply going in a direction really fast. Even if they could develop a craft that could go the speed of light --- and that seems unlikely --- then you are still talking about voyages not only of years but centuries and millennia between star systems. Each journey is a one-way ticket from your civilization.

So if an intelligent species is visiting us, they surely have found other ways to travel --- wormholes, interdimensional travel, folding space with geriatric spice, warp drive, who knows?

I am not suggesting UFOs are alien visitors. I have seen zero evidence of that, and there are lots of reasons against it.

But it isn't completely beyond the realm of plausibility.
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Old 06-14-2019, 04:05 PM
 
Location: Greenville, SC
4,643 posts, read 3,701,111 times
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Quote:
Originally Posted by Mark S. View Post
What if another planet didn't go through all that? It's possible they achieved a higher civilization hundreds, thousands, or even millions of years prior to us. Other civilizations might not be hundreds of years ahead of ours in terms of technology, but millions of years past us.
Sure - and if they're ten thousand light years away, they're not likely to be visiting us. Or to know that we even exist. And most of the items on my catastrophe list are going to be potential problems for any star system that develops intelligent life.

Quote:
So if an intelligent species is visiting us, they surely have found other ways to travel --- wormholes, interdimensional travel, folding space with geriatric spice, warp drive, who knows?
Or not. We simply don't know if any of this is possible. However -- I've been following NASA's experiments with the EmDrive - they've verified it works in a hard vacuum, and does indeed provide a thrust without expelling some sort of propellant (which by our current understanding of physics, shouldn't happen). Has NASA discovered a way to create a warp drive? Who knows - but it's fun to speculate. I hope there's something there. An article about the EmDrive and a potential warp bubble:

https://www.iflscience.com/space/war...ck-time-lunch/

On the down side - habitable zones may be rarer than first thought:

https://www.space.com/where-complex-...fe-exists.html
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Old 06-14-2019, 05:22 PM
 
Location: Madison, Alabama
3,580 posts, read 1,708,803 times
Reputation: 2803
If interested, the 3rd episode of "Unidentified" airs tonight on the History Channel.
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Old 06-14-2019, 05:49 PM
 
Location: Falls Church, Fairfax County
4,854 posts, read 2,907,438 times
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Quote:
Originally Posted by RocketDawg View Post
If interested, the 3rd episode of "Unidentified" airs tonight on the History Channel.
Spoiler: They find nothing.
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Old 06-14-2019, 06:40 PM
 
Location: Madison, Alabama
3,580 posts, read 1,708,803 times
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Quote:
Originally Posted by Old Guard View Post
Spoiler: They find nothing.
Of course not. And they never will, just like "Oak Island", "Expedition Unknown", and all the rest. But the programs are entertaining.
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