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UFO/ET… How sceptic are you ?
Posted: 05 August 2010 07:40 AM   [ Ignore ]   [ # 16 ]
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FTL is not a human limitation, it is physics. If there are advanced civilizations that have developed faster than light travel, where are they? Why aren’t they hopping about the galaxy like tourists?

Assuming we have the physics wrong and some day in the future we’ll be traveling from star to star like the Starship Enterprise is sheer wishful thinking.

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Posted: 05 August 2010 08:00 AM   [ Ignore ]   [ # 17 ]
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DarronS - 05 August 2010 07:40 AM

Assuming we have the physics wrong and some day in the future we’ll be traveling from star to star like the Starship Enterprise is sheer wishful thinking.

Yeah… Definitely… Even if such things are ultimately possible we will never get there…
(We will self destuct looong before then…) But something else out there might…

Well… not like in star trek but…

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Posted: 05 August 2010 08:37 AM   [ Ignore ]   [ # 18 ]
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AdrX - 05 August 2010 06:58 AM

When thinking about the question could ET be here, we shouldn’t assign
our own limitations to them like that… we should assume that they could
do things that seem impossible to us, rather we should look inwards, at
your our selves and our own limitations and think about how our limits
affect such possibility…

For example this: can’t go faster than light, and because of that distances
are too huge argument do apply, but not in the way most people think IMO

It applies to us, not them…

This is a very bad way to reason generally, so I can’t endorse it in this particular case either. The point of any reasoned argument, that is, any rational, informed opinion, is to follow the evidence. Claiming that we don’t have all the evidence or that we could be wrong about everything is a maximally foolish way to start. Clearly, we might not have all the evidence. Clearly, we could be wrong about everything. Perhaps we’re all just dreaming frogs. But if we’re going to go that route we shouldn’t even purport to be reasoning or arguing rationally. We should just say we’re BSing and have done with it.

If you want a reasoned argument for whether or not there are ETs, I’ve given something like it above. That is, FTL travel is impossible, warp drives and wormholes are probably impossible and certainly impossible for any but a very advanced civilization indeed. (And I should add that warp drives and wormholes would have measurable effects on their surroundings, such as emitting very high energy radiation, which we haven’t detected). So the probability of our having been visited by ETs is very, very small.

But perhaps we’re dreaming frogs, you say. Yeah, OK, but until you present evidence to that effect, we’re rationally justified to dismiss it as untrue and indeed silly.

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Posted: 05 August 2010 10:32 AM   [ Ignore ]   [ # 19 ]
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I don’t recall the specifics, but I seem to have read that quantum sized wormholes have been formed that lasted more than a billionth of a second before they collapsed, but it was demonstrated that larger ones cannot exist.

Occam

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Posted: 13 October 2010 05:35 PM   [ Ignore ]   [ # 20 ]
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Maybe the “aliens” live much longer than we do, so that hundred-year-plus interstellar voyages don’t faze them.

Maybe they have developed a way of putting themselves into some kind of suspended animation during the voyage.

Maybe they have advance bases on one of the moons of Jupiter - or deep underground or underwater on our own planet….

Maybe, maybe, maybe; all speculation, I know. But who knows what we are going to be able to do technologically in a century or two (think back to the technology we had available 200 or so years ago; anyone back then who had imagined television, cell phones, computers, or travelling halfway round the world in a few hours, would have been treated with ridicule at the very least, or more probably locked up). Then imagine a technological civilization a few THOUSAND years ahead of ours….

Let me put it this way. I simply don’t know whether we are being visited by spacefaring aliens; such evidence as we have is ambiguous to say the least. But it wouldn’t surprise me very much to one day in the near future see a group of Zeta Reticulans being interviewed on NBC News. I’d rate it as slightly more likely than Pat Robertson converting to Buddhism.

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Posted: 20 October 2010 10:53 AM   [ Ignore ]   [ # 21 ]
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Usually you can rely on the National Geographic channel, but even they are jumping on the bandwagon now!  Did you see American Paranormal this week?  They investigated the infamous “Phoenix Lights”, which I thought had been explained years ago!  http://en.wikipedia.org/wiki/Phoenix_Lights

Basically, many people said they saw a gigantic V shaped craft 1,500 feet long flying silently over Phoenix, Arizona.  This program spent most of an hour proving pretty convincingly that there was no way any craft that big could fly at all with any known means of propulsion.  I expected them to go from there to begin speculating about what other possible explanations there might be for what the witnesses think they saw, but they didn’t!  They just left it at that!  “Oh, we don’t know what it was…”  What a WASTE of an hour!

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Posted: 20 October 2010 11:10 AM   [ Ignore ]   [ # 22 ]
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advocatus - 20 October 2010 10:53 AM

Usually you can rely on the National Geographic channel, but even they are jumping on the bandwagon now!  Did you see American Paranormal this week?  They investigated the infamous “Phoenix Lights”, which I thought had been explained years ago!  http://en.wikipedia.org/wiki/Phoenix_Lights

Basically, many people said they saw a gigantic V shaped craft 1,500 feet long flying silently over Phoenix, Arizona.  This program spent most of an hour proving pretty convincingly that there was no way any craft that big could fly at all with any known means of propulsion.  I expected them to go from there to begin speculating about what other possible explanations there might be for what the witnesses think they saw, but they didn’t!  They just left it at that!  “Oh, we don’t know what it was…”  What a WASTE of an hour!

Well, yes. For anybody with an IQ over 100, our society is becoming rather a boring place, isn’t it? If you were the owner of the National Geographic, would you be more interested in the truth or in making money?  wink Thank Zeus for the internet.

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Posted: 20 October 2010 12:35 PM   [ Ignore ]   [ # 23 ]
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“Any KNOWN means of propulsion.” Exactly…....

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Posted: 20 October 2010 05:58 PM   [ Ignore ]   [ # 24 ]
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Theflyingsorcerer - 20 October 2010 12:35 PM

“Any KNOWN means of propulsion.” Exactly…....

Even with unknown means of propulsion the energy required for interstellar travel makes it a losing proposition.

If these long-lived advanced aliens exist, where are they? Our galaxy is huge. Even if we suppose there are advanced races out there around other stars they are A) very unlikely to find us in the first pace and B) even less likely to devote the resources and time necessary to come say hello to a civilization that probably won’t still be around by the time they get here.

Stars like our Sun make up less than 10 percent of the stars in the Universe. Large-celled life cannot evolve around the most common stars, red dwarfs, because the habitable zone is so close to the star the planet will be regularly washed with sterilizing radiation. Red dwarf stars are not stable like our Sun, they regularly slough off all kinds of radiation. Even with Type G stars such as our Sun, most are in binary systems. You think Phoenix is hot in the summer? Imagine what it would be like with another Sun in our solar system. Think Venus. Type O and Type B stars are orders of magnitude hotter than our Sun and do not live long enough for complex life to evolve.

That leaves us with single Type G stars as candidates for advanced civilizations. That is about two percent of the available stars, or approximately 20 million candidates in a galaxy that is 100,000 light years across by 3,000 light years thick, a volume of approximately 942,477,796 cubic light years. That is one possibly habitable star system for every 47 cubic light years, and that includes the crowded interior of our galaxy where life is unlikely to evolve due to radiation. If we assume that is 1/3 of the galaxy, we are left with less than seven million potentially habitable star systems. Considering everything that has to go right for complex life to evolve (planet of the right size in the right place, right chemical mix on the planet, a gas giant outside the habitable zone to attract most of the comets and asteroids after life begins to evolve etc) we can see how unlikely complex life is in our galaxy. Add to this there is absolutely no reason for evolution to “select” intelligence in the first place, and that our species was one bad winter from extinction 70,000 years ago, and the chances of an advanced civilization developing are not looking good.

Seven million potentially habitable star systems means that a one in 100,000 chance (which could be high or low) would mean there are about 70 instances of advanced civilizations forming in our galaxy. If the chances are one in one hundred (most likely very high) that leaves us with 70,000 advanced civilizations. Given the volume of our galaxy and the galaxy’s habitable zone, that means there is an upper limit of one civilization every 888 light years. Finding a habitable star 900 light years away is very nearly impossible because of the gas and dust blocking starlight and any signals they may be sending. If fact, the chance of finding such a civilization is so close to zero it does not matter.

I have not even gone into the chances of such a civilization existing at the same time we exist and could establish contact. Even if we assume advanced civilizations can only exist around stars that are approximately the same age as our Sun (a reasonable assumption because only second or third generation stellar systems have enough carbon and metals to support complex life and a civilization) the chances of intelligence evolving at the same rate are vanishingly small. What if intelligent life evolved instead of dinosaurs in another system? They would be 65 million years more advanced than us. If they developed interstellar travel they would have been here long ago. Most likely they did the math and concluded interstellar travel would drain all their resources with essentially zero chance of a return on their investment.

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Posted: 20 October 2010 06:11 PM   [ Ignore ]   [ # 25 ]
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DarronS, you forgot to go over how MANY galaxies there are estimated to be in the universe…which are many orders of magnitude farther away!

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Posted: 20 October 2010 06:27 PM   [ Ignore ]   [ # 26 ]
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I was thinking about other galaxies, but that just complicates things.

Do I believe there is other intelligent life in the Universe? Yes, but I doubt we will ever make contact. I also did not go into the chances of us (or them) recognizing a signal if we receive one. Even if we do receive what we recognize as a signal from another civilization we will have no means to decode it for meaning. We’ll need a Rosetta Stone to decode it. Given the vast volume of space we have no idea where to look, an alien civilization has no idea where to send such a transmission, and our civilizations will have to exist in the right times for any such one-way communication to result in a hit. Even if we do detect such a transmission it will probably be 1,800 years before we receive an answer to our reply. And that is just within our galaxy. Intergalactic communication is simply not a realistic expectation. If anyone in the Andromeda Galaxy sends us a message it will not reach us for 2.3 million years, and that is our closest galactic neighbor. Which is the reason I confined my speculation to our home galaxy.

I’m sure you knew that, Asanta, I just want anyone else reading this to realize how mind-boggling huge space is. It’s not like a trip down to the druggist. (Yet another Douglas Adams reference.)

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Posted: 20 October 2010 07:02 PM   [ Ignore ]   [ # 27 ]
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Mind boggingly huge is an apt description! Another thing to note…our galaxy isn’t even a very large one!

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Posted: 20 October 2010 07:09 PM   [ Ignore ]   [ # 28 ]
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Theflyingsorcerer - 20 October 2010 12:35 PM

“Any KNOWN means of propulsion.” Exactly…....

“We don’t know what means of propulsion aliens could use, so therefore we know they could use a form to do what we can’t.”  Logical Fallacy: Argument from Ignorance.

Since you were responding to a post that brought up the so-called Phoenix Lights, let’s look at what we do know:

We know an Air Force flight dropped flares on parachutes on that exact night at the exact time the lights were seen. 

We know the Air Force flares were in the exact area of the lights.

We know the Air Force flares were dropped in the exact shape as the lights. 

We know that flares went out of view in the exact area and shape as the mountain the flares were dropped behind. 

We know that no astronomers saw anything unusual, let alone potentially alien, that night - or any night. 

Of all the things we know and don’t know, I can pretty much say for certain, the Phoenix Lights were Air Force flares on chutes. 

We also know that we don’t have any evidence of any alien civilization, let alone one that comes to our planet only to hide from our best astronomers and professional sky-watchers yet can somehow be seen by untrained observers who really don’t understand what they see in the sky or how their eyes and brains can be easily fooled and tricked.

Such things can teach us more about human psychology and the desire to believe than advanced and exotic means of interstellar propulsion.

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Posted: 20 October 2010 07:10 PM   [ Ignore ]   [ # 29 ]
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Actually, our galaxy is pretty large. We were going over this in my astronomy class last night. Most of the galaxies we can see are about the size of the Milky Way or larger, but most galaxies are small satellite galaxies of larger spiral galaxies. Just as most stars are smaller than the Sun, most galaxies are smaller than the Milky Way. Our galaxy is about average for a spiral galaxy, and it would be incredibly beautiful if we were outside looking in. It would look something like M101.

143744main_hubble_spiral_2006.jpg
photo courtesy NASA

[ Edited: 20 October 2010 07:19 PM by DarronS ]
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Posted: 20 October 2010 07:17 PM   [ Ignore ]   [ # 30 ]
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Excellent points Rocinante.

Another point. There are tens of thousands of amateur astronomers going to dark sky sites every month to look at the wonders of the Universe, yet not one has ever reported seeing a UFO. You’d think if there were alien spacecraft darting about our skies avid amateur astronomers would have spotted one by now. Seems rather suspicious that the only people who see UFOs are those who do not know what is in the sky. Those of us who know an iridium flare from a shooting star don’t think of strange lights as alien spacecraft.

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