Study: No evidence of advanced alien life in nearby galaxies

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Profile River Song
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Message 1728658 - Posted: 24 Sep 2015, 22:57:37 UTC

Study: No evidence of advanced alien life in nearby galaxies
Fox News 9/24/15 3:43 PM PDST

While a sequel to the 1990s alien invasion flick "Independence Day" is in the works, moviegoers shouldn't worry about fact following fiction anytime soon. This is according to [a new report](http://arxiv.org/pdf/1508.02624v1.pdf) by the Netherlands Institute for Radio Astronomy, which determined that there are no signs of advanced alien life in 93 of our neighboring galaxies.

Does ET know this?
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Message 1728753 - Posted: 25 Sep 2015, 8:34:12 UTC

that doesn't mean there isn't Life out there?! ;)

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Message 1728798 - Posted: 25 Sep 2015, 13:45:01 UTC - in response to Message 1728753.  
Last modified: 25 Sep 2015, 13:47:06 UTC

I am too ignorant to vouch for their thinking, accuracy and methods. My take-away is that there are no Dyson Sphere's out there. I probably could have told you that with a high level of confidence.

I think that we will have enough problems just trying to find truly habitable planets out to 100 to 1000 light years. If we find some then we could focus our listening there--but probably only for a high-powered beacon. Even then there may be not a single such planet found.

All very speculative --but that's the nature of the uncertainty in this endeavor. Opinions matter little--facts are the key. At some points facts or the lack of them should lead to logical conclusions that are sound.
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Message 1728847 - Posted: 25 Sep 2015, 17:30:15 UTC - in response to Message 1728798.  

This is a different study than the one discussed in another thread but I draw the same conclusion - it's absurd. With the technology we have you could study Andromeda, right next door, for a hundred years and still not be able to confirm anything about alien civilizations.
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Message 1729170 - Posted: 26 Sep 2015, 15:58:56 UTC

An astronomical search for Dyson spheres seems a worthwhile endeavor, given our lack of knowledge about the technology of advanced stellar civilizations. Having said that, we should also realize that from our very limited perspective, predictions of what forms more advanced technologies will take are questionable, at best.

For all we know, Dyson spheres may be regarded as merely a quaint notion, by extraterrestrials with access to some better means of obtaining energy. Further, any form of waste heat produced by whatever technologies are actually in use may have be reduced to the point that we simply can't detect it.
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Message 1729214 - Posted: 26 Sep 2015, 18:11:05 UTC

According to science fiction science Dyson spheres couldn't be detected until accidentally stumbled upon. I wonder how a structure that totally encases a star to capture the energy of said star to power a civilization could ever be detected from another galaxy.
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Message 1729238 - Posted: 26 Sep 2015, 19:25:07 UTC - in response to Message 1729214.  

According to science fiction science Dyson spheres couldn't be detected until accidentally stumbled upon. I wonder how a structure that totally encases a star to capture the energy of said star to power a civilization could ever be detected from another galaxy.

Dyson spheres have had an appeal since they were first imagined, but has anyone ever sat down and tried to figure what it would take in real terms? The amount of raw materials required from a single solar system and what it would take to produce the components? The atmosphere on the interior surface over a million times the volume of all the planets in the system?
How many assumptions are we required to make in order for these things to be possible? Do all those assumptions really add up to something likely enough to be actively searching for?
If we really think anyone out there has that kind of know-how then why aren't we actively looking for Ringworlds, as well? They're just as plausible with the same assumptions, and probably cheaper, too.
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Message 1729239 - Posted: 26 Sep 2015, 19:25:58 UTC - in response to Message 1729170.  
Last modified: 26 Sep 2015, 19:26:27 UTC

Further, any form of waste heat produced by whatever technologies are actually in use may have be reduced to the point that we simply can't detect it.
All thermal systems with a heat source must have somewhere to radiate the heat. Stars do this by radiating it into deep space. If you put a Dyson sphere around a star, then the star radiates onto the interior surface of the sphere which gets hot. There being no perfect insulating material it follows the outside surface of the sphere must get hot. That surface radiates into deep space. There are no methods to escape the laws of thermodynamics.
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Message 1729252 - Posted: 26 Sep 2015, 20:02:07 UTC

The laws of thermodynamics may well hold for any technology, whether that involves a Dyson sphere, or not, but that wasn't my point. Greater efficiency in technology than we are currently capable of even imagining, might reduce its heat signature to the point that we couldn't detect it at intergalactic distances.
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Message 1729261 - Posted: 26 Sep 2015, 20:16:18 UTC - in response to Message 1729252.  

The laws of thermodynamics may well hold for any technology, whether that involves a Dyson sphere, or not, but that wasn't my point. Greater efficiency in technology than we are currently capable of even imagining, might reduce its heat signature to the point that we couldn't detect it at intergalactic distances.

No. Total energy of a sun or a Dyson sphere around a sun is the same. All you have done is change the frequency. It shifts towards the infrared and becomes brighter, in IR, than the star alone. Remember the energy frequency relationship of photons. Also remember the universe is more transparent in the IR than the visible. So if we could see the star without the Dyson sphere, we can see the Dyson sphere. Might not know what it is, but we know it is there.
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Message 1729326 - Posted: 26 Sep 2015, 23:21:37 UTC - in response to Message 1729261.  

Please explain how we are to look at a star in another galaxy that may be 300 million light years away or more.
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Message 1729353 - Posted: 27 Sep 2015, 0:44:28 UTC - in response to Message 1729326.  

Please explain how we are to look at a star in another galaxy that may be 300 million light years away or more.

The usual methods work fine.
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Message 1729381 - Posted: 27 Sep 2015, 3:05:30 UTC
Last modified: 27 Sep 2015, 3:05:56 UTC

As I indicated before, our own ideas about a superior technology are likely to fall far from the mark. Still, it's possible to try to imagine a way in which a waste-heat-emitting surface, like the outside of a Dyson sphere might turn out to be much less conspicuous in the infra-red than expected.
We know, of course, that a Dyson sphere would be made up of a multitude of objects, not a solid shell. Perhaps these objects could be fashioned so as to convert waste heat on their outer surfaces to even lower energy radio frequencies.

By their size, shape and distribution these objects might be arranged to direct radio frequency energy in particular directions. Such beams could conceivably be used to detect and characterize asteroids and comets with orbits that would intersect the sphere, and so, possibly damage it.
All of this could make for a Dyson sphere much less conspicuous in the infra-red, and much less likely to be detected.
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Message 1729418 - Posted: 27 Sep 2015, 4:36:23 UTC - in response to Message 1729381.  

As I indicated before, our own ideas about a superior technology are likely to fall far from the mark. Still, it's possible to try to imagine a way in which a waste-heat-emitting surface, like the outside of a Dyson sphere might turn out to be much less conspicuous in the infra-red than expected.
We know, of course, that a Dyson sphere would be made up of a multitude of objects, not a solid shell. Perhaps these objects could be fashioned so as to convert waste heat on their outer surfaces to even lower energy radio frequencies.

By their size, shape and distribution these objects might be arranged to direct radio frequency energy in particular directions. Such beams could conceivably be used to detect and characterize asteroids and comets with orbits that would intersect the sphere, and so, possibly damage it.
All of this could make for a Dyson sphere much less conspicuous in the infra-red, and much less likely to be detected.

If you go colder to radio, then it is even brighter than the normal background. Again remember the energy frequency relationship of photons. To transfer the same amount of energy with low frequency photons you need a lot more of them!

Also remember our body temperature is in the infrared. I don't think advanced beings would be happy with temperatures down to radio, say liquid nitrogen. Translation, they are going to keep the temperature of the sphere somewhat above the freezing point of water and somewhat below the boiling point of water; in the Goldilocks zone.
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Message 1729562 - Posted: 27 Sep 2015, 15:37:41 UTC

If the radio emissions are formed into narrow beams, as I suggested, there is a very good chance that they will not point in Earth's direction; they stand a good chance of not being detected by us, despite being brighter than background radiation in the radio range.
The inhabited objects making up the Dyson sphere could be roofed-over on the star-ward side with something like very efficient photovoltaic cells that convert light and 'room temperature' infrared to electricity. This could be fed to radio frequency emitters on the outer side of the objects.
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Message 1729746 - Posted: 28 Sep 2015, 8:59:47 UTC - in response to Message 1729252.  

The laws of thermodynamics may well hold for any technology, whether that involves a Dyson sphere, or not, but that wasn't my point. Greater efficiency in technology than we are currently capable of even imagining, might reduce its heat signature to the point that we couldn't detect it at intergalactic distances.

in 1930 cars had about 8liter engines with about 30HP...
now we have 1liter engines with up to 100HP!

OK, d efficiency goes up...but also d consumption - 'cause of the availability of d engines & cars!
;)

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Message 1735725 - Posted: 20 Oct 2015, 20:47:52 UTC
Last modified: 20 Oct 2015, 20:47:52 UTC

Could this be the reason?

Earth was one of the universe’s first habitable planets

Earth was one of the first habitable planets in the universe, according to a new study.

We were among the first 8 per cent of worlds that could potentially support life when we came into being 4.6 billion years ago, according the astronomers behind the study. Many of the other Earth-supporting planets won’t turn be around for some time — and are likely to come about after our own sun burns out in six billion years.

Astronomers looked at data from the Hubble and Kepler space telescopes to come to the conclusion. The latter was built in part to look for the kind of earth-supporting planets that could be sustaining life elsewhere in the universe.
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Message 1735879 - Posted: 21 Oct 2015, 9:10:32 UTC

Imagine what would happen, if human weren't dominant species...& that dinosaurs never died by a catastrophic event in past?!

Would dinos still use dogs & monkeys for a 1st flights into Earths orbit?
:/

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Message 1736268 - Posted: 22 Oct 2015, 20:34:01 UTC

The study in question was searching for signs of a Type III civilization capable of harnessing the energy of an entire galaxy via extreme mid-infrared emission. The signs they did find were explained away by natural phenomena.

First of all, that does NOT mean there is NO life, or even no ingelegent life in those galaxies. It means they did not find EVIDENCE of Type III. We're a type I civilization, and there is a whole class of Type II still. That means they would not have even seen an exact clone of earth in their study.

Please read the papers, and not just media headlines. :)
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Message boards : SETI@home Science : Study: No evidence of advanced alien life in nearby galaxies


 
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