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kashi
2003-Sep-28, 01:29 AM
http://www.sciam.com/article.cfm?articleID...B81809EC588EF21 (http://www.sciam.com/article.cfm?articleID=0009CDEA-33FC-1C74-9B81809EC588EF21)

If civilisations only take say 10000 years to evolve to the stage where they can send radio transmissions, why haven't we heard from aliens. Even if civilisations take 1 million years to evolve to state where they can travel to other solar systems, the galaxy should still be swarming with life.

What's your opinion? Why haven't we heard from alien civilisations?

rahuldandekar
2003-Sep-28, 08:25 AM
I can see these possiblities:

1)Maybe they think we are too primitive.
2)Maybe they haven't evolved into advanced forms yet.
3)Maybe they have evolved at a different size or are of a different composition, and so, have invented other methods of communicating.
4)Maybe there exist no other 'civilised' beings.
5)Maybe we are the only being in existence.

imported_ROB
2003-Sep-30, 08:57 AM
perhaps they have advanced at the same rate as us but probably faster and are far to far a way to even have registered any of our earth based radio waves theres a lot to look for maby they arnt even looking its a matter of time though

imported_Draco
2003-Oct-01, 02:14 AM
Yeah they probably are way too advanced to send radio waves...but if they are, they would have had to pick up our transmissions...Or maybe they haven't advanced as much as us..or maybe they are this magical race somewhere:p That'd be cool:D Like the books by Phillip Pullman:) Not that i've read all of them, but reading 1:)

imported_ROB
2003-Oct-01, 02:59 PM
WHAT THEY ARE JUST STUDYING US FROM A FAR WAITING TILL WE COULD HANDLE THE FACT THAT "WE ARNT ALONE" MABYE THERE SEE ALL THE HATE HERE ON EARTH AND DONT WANT TO INTRODUCE THERE EXSISTANCE YET. TILL WE ARE WORTH MEETING!!!!!

engelbach
2003-Oct-01, 05:37 PM
I don't know about the 10,000 or one million years. We might not have evolved at all if the dinosaurs hadn't been fortuitously wiped out. And I think it's unlikely that we will ever develop practical interstellar travel for human beings.

The galaxy may be teeming with life, but the odds are against its being intelligent. Intelligent aliens may be so rare that they are too distant for radio waves to/from them to have yet arrived. Give it another million years or so.

Prime
2003-Oct-01, 05:56 PM
Their probably here;

http://www.alienwar.com/page9.htm

After reading the 5 or so page excerpt, go to manuscript info, scroll down to home and the whole 100+ page manuscript can be read, on down the page.

Some of the other stuff on the site is speculative to me, but the author claims to have been gone for 2 weeks, at their invitation.

Prime

astrophysicsrose
2003-Oct-01, 11:47 PM
WHAT THEY ARE JUST STUDYING US FROM A FAR WAITING TILL WE COULD HANDLE THE FACT THAT "WE ARNT ALONE" MABYE THERE SEE ALL THE HATE HERE ON EARTH AND DONT WANT TO INTRODUCE THERE EXSISTANCE YET. TILL WE ARE WORTH MEETING

REPLY: Feel the same. Our perceptions of life, advanced technological society, contact, theories on how many years it takes to create a species termed a civilization, all this is most likely a non-entity when it comes to true contact. We humans simply engage in our own subjective reality of the universe at large and ponder our so called place within it without taking a good subjective look at our own life forms and the fact that our place within our own selves is filled with extreme negative uncreative so called life forces.

If life is universal, then human influence cannot be that positive within universal eternity. With this reality in mind, perhaps those advanced life forms out there are honestly not interested in us over here except to steer as clear away as possible.

What we influence is where we learn from, and it seems that we cannot locate anyone with our SETI program thus far. Maybe we are conducting the search in a manner truly opposite of something else within creation's existence, and we are just going about it in all the wrong way. Maybe we need to seek contact through a wormhole type of method, or just begin the search in another manner. Why, because we haven't thus far succeeded with what we think we know. There must be another answer, another method that is totally escaping us.

withaGee
2003-Oct-01, 11:47 PM
If the behavior of the "Family of (hu)Man" towards each other is any indication, it might be best that no extraterrestrials stop by Earth. Assuming that there is intelligent life elsewhere, the prohibitively immense distances between likely star systems may be part of the plan of a Supreme Being. -But, like engelbach says, let's give it another million years.

I realize that this is a more philosophical (and perhaps cynical) than scientific opinion. I'll enjoy hearing more of what others have to say about

-G

MarQ
2003-Oct-02, 12:54 PM
I just think it is the height of arrogance to think our pale, blue dot has been touched by the mystery of intelligent life.

Haglund
2003-Oct-05, 10:16 AM
I can think of a few explanations:
The chance of intelligent life to arise is low. (I don't know how common life is, but it's just a thought.)
Intelligent life does not necessarily have to form a technological civilization. Therefor we would never notice them unless we went there.
Some of the technological civilizations might destroy themselves.
Some of them might have existed but was annihilated by an asteroid etc.
If they are at our level of technology, chances of hearing them would be small unless they sent a strong message directed at us.
If their intelligence and technology is superior to ours, they may think they have nothing to gain by establishing contact, or they want to leave us alone.

Just a few thoughts there.

astrophysicsrose
2003-Oct-05, 12:43 PM
I can think of a few explanations:

The chance of intelligent life to arise is low. (I don't know how common life is, but it's just a thought.)
Intelligent life does not necessarily have to form a technological civilization. Therefor we would never notice them unless we went there.
Some of the technological civilizations might destroy themselves.
Some of them might have existed but was annihilated by an asteroid etc.
If they are at our level of technology, chances of hearing them would be small unless they sent a strong message directed at us.
If their intelligence and technology is superior to ours, they may think they have nothing to gain by establishing contact, or they want to leave us alone.

REPLY: But, in essence, these are the explanations postulated by Carl Sagan. Good postulations non-the-less, but now, we need some honest clarification, and perhaps a rehash of the entire method of conducting the search as well as a grasp at who and what we are and why we haven't thus far made contact. Perhaps we need to come of age, and begin to search for a new categorical imperative on the whys and wherefores of conducting the search.

Haglund
2003-Oct-05, 04:30 PM
Originally posted by astrophysicsrose@Oct 5 2003, 12:43 PM
I can think of a few explanations:

The chance of intelligent life to arise is low. (I don't know how common life is, but it's just a thought.)
Intelligent life does not necessarily have to form a technological civilization. Therefor we would never notice them unless we went there.
Some of the technological civilizations might destroy themselves.
Some of them might have existed but was annihilated by an asteroid etc.
If they are at our level of technology, chances of hearing them would be small unless they sent a strong message directed at us.
If their intelligence and technology is superior to ours, they may think they have nothing to gain by establishing contact, or they want to leave us alone.

REPLY: But, in essence, these are the explanations postulated by Carl Sagan. Good postulations non-the-less, but now, we need some honest clarification, and perhaps a rehash of the entire method of conducting the search as well as a grasp at who and what we are and why we haven't thus far made contact. Perhaps we need to come of age, and begin to search for a new categorical imperative on the whys and wherefores of conducting the search.

But, in essence, these are the explanations postulated by Carl Sagan. Good postulations non-the-less, but now, we need some honest clarification, and perhaps a rehash of the entire method of conducting the search as well as a grasp at who and what we are and why we haven't thus far made contact. Perhaps we need to come of age, and begin to search for a new categorical imperative on the whys and wherefores of conducting the search.


Personally I think we should listen more than we do now, and perhaps be more active and not passive. I think we should send out messages to some selected targets. Maybe it will work, maybe not. The targets could be better selected if we could search for earth-sized exoplanets.

Planetwatcher
2003-Oct-06, 05:12 AM
Perhaps they have recieve our radio and TV transmission, and decided to not reply, or come knocking. Would you?

I believe the first TV transmissions sent into space related to Hitler. Those transmissions would be around 80 LY along by now.
Then if they were enroute, and saw Walter Kronkite from the early 1960s reporting Vietnam, arms race, cold war, and possible nuclear anniliation of each other, they may call a committe meeting.

Then to see the 1972 US election, and watergate which followed, along with a president who said, "Read my lips" what would they think?

Follow with exclusive footage of two major wars at the very site man was created mind you, and I think they' be turning around and asking Scotty for more warp power to head home before we see them. :ph34r:

Matthew
2003-Oct-06, 06:35 AM
Our galaxy is about 100000 ly across then it would take at most 100000 years to recieve radiowaves from them. We've only been able to recieve and transmit radio waves for about 100 years, maybe radiowaves from other races might have been reaching Earth for thousands of years but we never had the technology to 'hear' them. What if they anniahlated themselves and their last signal came to Earth 150 years ago. We wouldn't have heard them.

kashi
2003-Oct-06, 01:10 PM
There is another possibility. That we have heard them...that they may have even visted here (now or many thousands of years ago). Obviously this is just speculation, but so is this is entire thread!

Also...I love to play devil's advocate (in case you haven't realised), and although I have frequently highlighted how barbaric the human race is on this forum, let's not forget the great cultural acheivements of humanity, many of which have been broadcast into interstellar space. I wonder if the appeal of J.S. Bach is not just global, but also Universal (at least galactical).

Kashi

StarMikeBest
2003-Oct-30, 03:08 AM
Hi folks. Mikey here (http://members.aol.com/StarMikeBest)

If the universe is 13.7 billion years old, and
If stars came along 2 million years later, and
if the solar system is 4.6 billion years old, and
if life first emerged 1 billion years after Earth formed, and
if we have only had a grasp on "wassup" for 100 years or so, then
it would appear we may be late arrivals to a gazillion parties that were held and are over.
We may have come along pretty late in the game. Most of the "party" goers have arrived, done their thing, and left.
And don't take our efforts of monitoring radio since 1960 as proof one way or another.
There are a gazillion radio frequencies to monitor.
And the biggee --
To receive a signal, we must be "exactically" the same distance from the source in light years as the length of time ago that a message left there.
That coincidence fo time and "time?" amkes it very iffy that we will hear anything.
If an interstellar message passed by Earth 100 years ago we would have missed it.
If an interstellar radio message arrives in another 100 years we will miss it also because we will, by then, be beyond "antiquated" radio technology.
Check out The SETI Institute (Search for Ectraterrestrial Intelligence) (http://www.seti-inst.edu/general/Welcome.html) for up to date info by real scientists doing real science.
Good luck -- bon chance

Haglund
2003-Oct-30, 08:14 AM
Even if we invent something better than radio to communicate, we have no idea if the others have done the same. Radio will be one of the things we might have in common, if they're about to communicate at all.

rahuldandekar
2003-Oct-30, 09:00 AM
We need to consider another point.

We have emerged on the earth 35,000 years ago as a species, but radio astronomy began just about 50 or so years ago, that too due to co-incidence.
If that co-incidence had not hapenned, we would probably have had to wait for anything between another 10 years to infinity for it's invention.

We can surmise that even if aliens exist, they may have developed other methods of communication, and the probablity of them having radio astronomy as a feild at the same time as us is, I believe, very small.

kashi
2003-Oct-30, 10:06 AM
Yeah but once you've got it, it doesn't go anywhere.

Haglund
2003-Oct-30, 12:55 PM
I see no reason why a culture that managed to develop devices to transmit and observe electromagnetic radiation with those wavelengths would suddenly stop doing it.

all_isone
2003-Oct-30, 08:37 PM
how can you expect aliens to think/act/communicate like humans do?
it's too egocentric

Haglund
2003-Oct-30, 10:39 PM
If they are a culture with science and technology, it's impossible that they could have missed electromagnetic radiation... Sooner or later they would learn about it.

kashi
2003-Oct-30, 11:17 PM
I agree...it's not just some arbitary concept.

zephyr46
2003-Oct-31, 05:13 AM
I think for intersteller transport to be invented, you need a good reason. I think it's more likley to be developed quicker in star clusters or multiple star systems, with multiple planets, is Alpha Cen has planets chances are they'll devlo[pe star travel before us. Our lunar expadition came about through our clocetive discoveries and the close proximity of the moon.

kashi
2003-Oct-31, 08:05 AM
well...less technology would be needed if your destination was closer.

Haglund
2003-Oct-31, 08:20 AM
Originally posted by zephyr46@Oct 31 2003, 05:13 AM
I think for intersteller transport to be invented, you need a good reason. I think it's more likley to be developed quicker in star clusters or multiple star systems, with multiple planets, is Alpha Cen has planets chances are they'll devlo[pe star travel before us. Our lunar expadition came about through our clocetive discoveries and the close proximity of the moon.
Makes sense. It would be much more difficult for us to begin interplanetary travel if it meant we had to go to another planet right away without "practicing" on closer objects...

kashi
2003-Oct-31, 11:41 AM
But interplanetary travel would also be less of an acheivement if the the destination was near.

Matthew
2003-Oct-31, 11:28 PM
But interplanetary travel would also be less of an acheivement if the the destination was near.

Yes, but you need to start somewhere. Once you do something small, you feel more confident about doing something bigger, with more risks.

Learn to walk before you learn to run.

OverTheStars
2003-Nov-14, 02:54 PM
knowing the world today, we would probably get scared and try to kill them.

Planetwatcher
2003-Nov-15, 01:21 PM
Perhaps such cultures do know about electromagnetic radiation, but for reasons we can't decern don't use it. Or may be listening but choose not to reply.
Would you, if you were afar and learned about us from what we transmitt,
considering the violence, the porno, the conflicts and all else?

Haglund
2003-Nov-15, 01:57 PM
Originally posted by Planetwatcher@Nov 15 2003, 01:21 PM
Perhaps such cultures do know about electromagnetic radiation, but for reasons we can't decern don't use it. Or may be listening but choose not to reply.
Would you, if you were afar and learned about us from what we transmitt,
considering the violence, the porno, the conflicts and all else?
It's difficult to predict the actions of another intelligent technological species, especially how they react to what we do to and among ourselves-

DippyHippy
2003-Nov-16, 03:20 AM
Maybe they *have* been listening and are on their way...

...or...

...if they'd only received the transmissions up to a point and had held a meetng to discuss us, maybe they decided that we'd self-destructed or that we were likely to self-destruct while they were on their way (thereby making an expensive mission a worthless gesture)

Planetwatcher
2003-Nov-16, 10:44 PM
I just hope with all those meetings they don't practice the Delbert principle. :D
Which those of you not from the U.S. likely don't know what I'm talking about.

Delbert is a comic strip by Robert Adams which portrays much of what's wrong in the U.S. capital market. IE.. too many meaningless meetings, overproduction on non-essentials, too many middle level management members, unperportional values placed on high production with little or no regard to quality. :angry:

In short the Delbert princile is simply put... Take the stupidest, most poorly trained, most incompentent, closed minded, least willing to change, idiot in a given industry, and give him the job where he can create the least amount of damage.
Top level management. :rolleyes:

If those E.T. s are practicing some cosmic level of the Delbert principle, I'm glad they are not here, and can easily understand why they haven't arrived yet.
Because they are somewhere on the other side of the galaxy wondering if they should have made that left turn at Andromeda. :lol:

Haglund
2003-Nov-16, 11:26 PM
Oh yeah I've known Dilbert for several years, think it's a great comic :)

imported_Ziggy
2003-Nov-18, 09:24 PM
I acn't answer those questions (it takes too long). But I will answer the post question. I think that our best chance of finding life will be looking at the star Tau Bootis. According to NASA they found a blueish-white planet in orbit around it. Which of course opens the possibilities for life.







"Earth is like the cradle of life, but one cannot live in the cradle forever"

QJones
2003-Nov-19, 09:58 AM
I read on the NASA site (but there weren't any sources backing up the statement) that our signals from Earth, could be detected using earth technology levels up to forty light years away. Basically, that's how loud our signals are. Neat huh?

erasium
2003-Nov-19, 08:08 PM
just testing, wrote a long reply and it got re-plyed! Want to see if this gets in.

erasium
2003-Nov-19, 08:44 PM
ok, now it seems to work. I think we haven't seen them because of the time it takes for signals to cross, we are at no special time in the evolution of either our universe, our galaxy, or our sun so we have been kind of randomly plopped down on this planet in your average area seemingly good for the evolution of life. That is to say in a favored distance from the center of the galaxy where the supply of metals is higher than in the stars at the fringe but away from the energy excesses near the center of the galaxy. Statistically speaking we are in the right band of stars at the right distance from the center our galaxy for our kind of life. So one result of that kind of analysis is where you point your detection instruments, light, radio, whatever. It would make more sense to point your sensors left and right from the line going to the center of our galaxy. The chances of a signal would go down again if you point your sensors away from the center of the galaxy. I dont personally do that kind of work so dont know if they take that into consideration but they should. The other problem as already pointed out is the galaxy being 100000+ light years across means if a civilization came into technology 25000 years ago but they live 50000 light years away, it doesnt matter WHAT they do, we wont detect them for another 25000 years so dont hold your breath!
If a civilization reached class III and were on billion years old we would see the energy anomolies already within one billion light years, a large number indeed but only a fraction of the size of the whold universe, if they were 2 billion light years away and were "only" around for one billion years, again, dont hold your breath!
Another problem is with our basic assumtion they will HAVE to use so much energy to grow to galaxy wide size. For instance if the best we can do for refrigeration today is say, 100 watts to run it then if we develop insulation one million times more efficient then it seems ok to assume it would take something like one million times less energy for the same capacity at least as far as keeping in the cold once you have achieved your desired temp. Another example is the energy needed to accelerate a car vs the energy needed for a spaceship. If you look at a car, you have that nice highway to accelerate against, you are actually attempting to change the rotation of the earth with your accel but it takes about 32 HP to accelerate 555 pounds in a car on the earth at one G, 32Ft/sec^2. In space that same 555 pounds wants about 60,000 hp for the same acceleration of that 555 pounds. sucks actually. So suppose they come up with a way to accelerate in space like we accelerate on a highway, for instance, if we make the space elevator work, it will be essentially a vertical highway where the thrust will be trying to bring down the sattellite but the forces of orbital mechanics will prevent that up to a point and so allow you to use thousands of times less energy to at least get into orbit. Now once in orbit you are stuck again with stupid rockets and back to 60000 hp to accelerate a motorcycle size weight. You might contemplate using lasers for power but you are still stuck with the same general power requirement, you just have need less fuel on board the craft, it just moves the requirement to a planet or orbiting system of some sort. But that is only for us at our primitive level of understanding. They may have methods to make, say, a wormhole to get where you want to go needing the power of a D cell. Since we are vigorously debating the possibility or the impossibility of a wormhole at all, we certainly cant make a valid assesment of the energy requirement for such a thing. Like someone said, they may not use RF, light or anything like that to communicate, maybe they dont even NEED to communicate which means they dont need ANYTHING! But suppose they need to comm each other, WE think they are limited to the speed of light but we already know superimposed particles are linked together in such a way as to suggest faster than light something or other is going on like Big AL said "spooky action at a distance" So maybe they use modulated tachyons or something, hell we dont even know if tachyons can EXSIST much less modulate the buggers! We make all these assumsions but we dont have the experience neccessary to make real evaluations of these things. The fact that we DONT see energy anomolies means either they are so far away the signals havent gotten hear or they use faster than light systems at least for communications and maybe transport too.

Diane
2003-Nov-20, 07:41 PM
well, what I see a great danger of happening in our civilisation is this;- intelligent life develops, but as it becomes more intelligent the reproduction rates slow down to the level where they are not sustaining the population. Meanwhle the less intelligent parts of the population reproduce like crazy and eventually the intelligence levels of the entire planet drop to such a low level that the planet regresses and so never becomes able to get much past where we are now. See unmarried mums with 6 children by 6 fathers supported by the state continuing to breed whilst professional classes delay having families until too late or choose not to have children at all. Maybe a load of rubbish, but there might be a tiny element of why we do not communicate with other life forms - maybe they all now live on state benefits! :)

kashi
2003-Nov-20, 10:16 PM
Welcome to the forum Diane.

There are lots of possibilities that could limit a species' intelligence in the long term. Hawking said in a speech near the end of the cold war, that perhaps the reason we haven't been contacted by alien civilisations, is that most civilisations tend to destroy themselves when they reach our stage. A scary thought indeed!

Kashi

Haglund
2003-Nov-20, 11:22 PM
Well, the thought of civilizations destroying themselves... I think both alternatives are possible, that they will or they will not. What are the reasons why they would? I think it is the fact that even the most intelligent species is still an animal with all the instincts and all those things. Combine that with intelligence, and what might happen? Technology is used to satisfy our instincts and needs, it's an extension of ourselves. It makes us stronger, faster and more powerful. It can improve our lives, make our existence much safer, we can get more food and we can find answers about our world by exploring it. But we also make the ways we can potentially attack the tribe next door much more efficient as well. Where we used to use primitive weapons like our own hands, or something else like sticks and stones, we now use guns, tanks, jetfighters and nuclear ICBMs. We haven't evolved very much, but our technology has, and we certainly know how to use it to our advantage. The fact that we invented nuclear weapons is not a new problem, but it does show us how important it is to deal with an already existing problem. Anyway, what are the reasons a technological civilization would not destroy itself? The will to live, if nothing else. The idea that the world can be different. And, of course, technology can help us with that. The whole thing is how you use it.

DippyHippy
2003-Nov-22, 02:54 AM
Ziggy, I'm not aware that anyone's detected the colour of any exoplanet... where does it say this world appears blue-white?

We aren't able to visually detect exoplanets just yet...

Manchurian Taikonaut
2004-Mar-05, 08:42 AM
http://www.esa.int/export/esaSC/SEMYZF9YFD...DD_index_0.html (http://www.esa.int/export/esaSC/SEMYZF9YFDD_index_0.html)


The vast majority of planetary detections so far has been achieved using the radial-velocity technique from ground-based telescopes. The method requires the light from a star to be split into a spectrum, rather like water droplets in the atmosphere splitting sunlight into a rainbow.



http://cfa-www.harvard.edu/afoe/they-are-e...-everywhere.gif (http://cfa-www.harvard.edu/afoe/they-are-everywhere.gif)



Gliese gas planet, child of aldebaran, Upsilon Andromedae b, Goldilocks, iota Horologii b, PSR 1257 pulsar planet, Tau Bootes system, 51 Pegasi b, 70 Virginis b, "hot-jupiter" in Delphinus, Bellerophon, Rho Coronae Borealis b, Epsilon Eridani planet, 55 Cancri b & c planets.


http://news.bbc.co.uk/1/hi/sci/tech/1111427.stm

http://www.cnn.com/2003/TECH/space/01/07/u...r.ap/index.html (http://www.cnn.com/2003/TECH/space/01/07/us.planetsear.ap/index.html)

The scientists from the University of California, Berkeley, US, say a star 123 light-years from Earth is being circled by two objects, one of which may be the biggest planet ever found
On 1/17/96 Geoffrey Marcy andPaul Butler announced the discovery of planets orbiting the stars 70 Virginis and 47 Ursae Majoris. 70 Vir is a G5V (main sequence) star about 78 light-years from Earth; 47 UMa is a G0V star about 44 light-years away. These were discovered using the same doppler shift technique that found the planet orbiting 51 Pegasi

http://www.seds.org/billa/tnp/other.html

Galactic astrology???

http://www.saros.zynet.co.uk/ingalast.html


http://www.ciw.edu/IAU/div3/wgesp/

High contrast imaging of extra-solar planets and brown dwarfs. Prof. Ge's group and his collaborators, at Princeton University, Harvard-Smithsonian Center for Astrophysics and Ball Aerospace Technology Inc. are developing new coronagraph techniques for the NASA Terrestrial Planet Finder mission, to be launched in 2015. They have successfully demonstrated the feasibility of a shaped pupil coronagraph for high contrast imaging in the lab, as well as, at the astronomical telescope. In the lab, they have reached ~ 10-6 contrast at ~ 5 times diffraction-limited Airy disk size. At the Mt. Wilson 100inch telescope with a high order adaptive optics system, they have reached ~ 10-4 at the ~ 10 times diffraction-limited Airy disk size. They have successfully detected faint companions around nearby stars using this new high contrast imaging technique. They are working on developing new techniques for further improvement in image contrast. Their goal is to reach ~ 10-10 contrast to allow TPF to detect Earth-like planets in space in next decade. Prof. Ge's group is also taking advantage of the new high contrast imaging techniques to search for brown dwarfs and giant planets around nearby stars. To date, they have detected two transition objects, and a brown dwarf candidates
http://www.iac.es/project/jovian/
http://www.esa.int/export/esaSC/SEMZVI5V9E...xploring_0.html (http://www.esa.int/export/esaSC/SEMZVI5V9ED_exploring_0.html)

http://www.astro.psu.edu/users/jian/exoplanets.htm
http://news.bbc.co.uk/1/hi/sci/tech/3177684.stm