What are the ways we can search for alien life?

[mfb]

Then again perhaps a technological species becomes inevitable at some point once life has evolved beyond the level of plants.

If something would have ended life on Earth 1 million years ago Earth would never have developed such a species.

 

[rootone]

If something would have ended life on Earth 1 million years ago Earth would never have developed such a species.

True, but life here seems to have survived near extinction several times.
It does seem to have the property of being very persistent once started, though from a sample of one planet we can't really know that.
Could be that life hanging on here after several mass extinctions was just extrordinarily lucky.

 

[mfb]

Sure. For every planet with life where a technological species evolves there could be many others where it does not. We know at least one event where our species was close to extinction (the genetic bottleneck is disputed, the massive reduction in population is not as far as I know).

And there is always the timescale. The sun becomes more luminous over time, which reduces the CO2 content of the atmosphere. At some point, it will become too low for photosynthesis. In roughly a billion years the greenhouse effect (based on water, not CO2) kills whatever remained on the surface or in the oceans.

 

[DaveC426913]

And there is always the timescale. The sun becomes more luminous over time, which reduces the CO2 content of the atmosphere. At some point, it will become too low for photosynthesis. In roughly a billion years the greenhouse effect (based on water, not CO2) kills whatever remained on the surface or in the oceans.

A billion years is oodles of time to evolve an alternate energy extraction mechanism.

 

[Chronos]

I would argue that technology is merely an extension of intellect. Many creatures on Earth exhibit undeniable ability to communicate or uttilize simple tools, e.g., birds, otters, chimps yet we deny they possesses sentience because their technology appears primitive and unevolving. It strikes me as hubris to constrain our assessment of their level of intelligence on our own terms. I merely suggest aliens may be similarly diverse , evolve at their own pace and in their own way. Many may be far more technologically advanced than us and communicate in ways we cannot imagine.

 

[Monsterboy]

That's a fairly fanciful definition of intelligence, IMO. I think intelligence is, by definition, distinct from complex behavior. Bees certainly have complex behavior, but the reason they haven't contacted us is because they are not sentient.

I think bees and ants don't really think about organization, (they didn't organize themselves consciously) they are just biologically programmed to do what they are doing , that's why they can't be called intelligent and that's why there is no technological development.

I would argue that technology is merely an extension of intellect. Many creatures on Earth exhibit undeniable ability to communicate or uttilize simple tools, e.g., birds, otters, chimps yet we deny they possesses sentience because their technology appears primitive and unevolving.

The main difference between the animals you mentioned in this post and humans is the way knowledge is handled , humans activity teach their young about what they already know so that their younger generation won't have to rediscover and reinvent everything again and so they can explore and acquire new knowledge,animals don't do that so every generation has to relive it's previous without any accumulation of knowledge, hence no improvement in technology.
Some information on culture and group learning etc
http://www.eva.mpg.de/psycho/pdf/Publications_2013_PDF/Moore_2013.pdf

 

[Chronos]

So how do bees and ants learn their societal roles in the absence of nurses and teachers? I've not seen any such studies. I would guess they wander around pretty much aimlessly and probably are killed by fellow colonists to constrain food losses due to their unproductiveness.

 

[Monsterboy]

https://en.m.wikipedia.org/wiki/Ant

Many animals can learn behaviours by imitation, but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of Temnothorax albipennis will lead a naive nest-mate to newly discovered food by the process of tandem running. The follower obtains knowledge through its leading tutor. The leader is acutely sensitive to the progress of the follower and slows down when the follower lags and speeds up when the follower gets too close.[92]

Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out fewer and fewer times. A month later, the successful foragers continued in their role while the others had moved to specialise in brood care.

Hmm...looks like ants do group learning but I don't understand to what level they actually 'think' of themselves as one colony with some kind of identity.

Another interesting article on ants http://www.scientificamerican.com/article/weve-been-looking-at-ant-intelligence-the-wrong-way/

Evolution has equipped ants with a distributed system of specialised modules interacting together. These results demonstrate that the navigational intelligence of ants is not in an ability to build a unified representation of the world, but in the way different strategies cleverly interact to produce robust navigation.

We need to keep in mind that this is only our current level of understanding. Even insect brains are far too complex to be fully understood in the near future.

Looks like my initial guess that ants don't learn from their previous generation is wrong but the reason why they didn't develop technology (another guess) is that they don't try to improvise on what they learn from others (they don't innovate) each ant just blends into a 'specialized module' and doesn't think differently.

There are several human civilizations or tribes that are also stuck at a certain level of development, certain tribal people in South America,Africa and South East Asia are stuck in the stone age, maybe it is the result of culture? Some cultures encourage thinking and doing things differently and some others don't.

http://www.dailymail.co.uk/sciencet...hange-job-grow-older-scientists-discover.html

The ants that nursed the queen and the young tended to be young, slightly older ants were responsible for cleaning the colony and the third group of ants, usually the oldest, foraged for food outside the colony.

*They also discovered that ants only socialise within their career groups

The six-year project by scientists at the University of Lausanne in Switzerland, accumulated the largest ever data of ant interactions.

.

The question becomes - given these obvious signs of intelligence - why have they made no apparent attempt to contact us? Perhaps they have, but, concluded our minds lack sufficient awareness to recognize their efforts, therefore we are not sentient..

I think the above articles suggest that ants are intelligent but they don't have a collective identity like "Hi,we are ants from earth(or ants from a colony) " , the colony is divided into several career groups and each group is worried only about it's job and not of the entire colony, there is no significant communication between these groups.

 

[newjerseyrunner]

Intelligence isn't enough to be interesting, they have to have science. Intelligence and even technology can only go so far without science. Lots of creatures make tools, they can understand that something works. Only humans try to understand WHY.

 

[DaveC426913]

Intelligence isn't enough to be interesting, they have to have science. Intelligence and even technology can only go so far without science. Lots of creatures make tools, they can understand that something works. Only humans try to understand WHY.

I beg to disagree. Science or no, I would be extremely interested to carry on a conversation with an intelligent species. I suspect there is a large spread on the continuum of intelligence between mere "animal intelligence" and "science-capable intelligence."

Imagine if Dolphins were intelligent enough to share with us their views on art, philosophy, relationships, love and death.

 

[mfb]

I would be extremely interested to carry on a conversation with an intelligent species

Me too, but at least in the near future we won't get that chance unless they are in the solar system or have technology for interstellar communication.

 

[DaveC426913]

Me too, but at least in the near future we won't get that chance unless they are in the solar system or have technology for interstellar communication.

Or if they have extremely good hearing. 'course it would still be a one-sided conversation...Unless... unless they spoke in radio wavelengths as well as sensed in radio wavelengths.
We have fallen prey to another example of Earth-centrism.

 

[newjerseyrunner]

I beg to disagree. Science or no, I would be extremely interested to carry on a conversation with an intelligent species. I suspect there is a large spread on the continuum of intelligence between mere "animal intelligence" and "science-capable intelligence."

Imagine if Dolphins were intelligent enough to share with us their views on art, philosophy, relationships, love and death.

I would suspect we are on the very very very bottom of that continuum. We just walked out of nature and started separating ourselves from it. We're just starting to look at the programming that makes us, and learning how to play with it. I would bet that most species would do this, and even with just minor tweaks here and there, over enough time, a species would be unmeasurably more intelligent. Some species will wholly embrace the new technology and greatly boost their collective intelligence for several generations. Self improving machines are a whole different can of worms.

If you take some of the smartest humans that have ever lived: Einstein, Newton, Imhotep... even they probably would barely register any differently than a chimp on an alien intelligence test.

I would be extremely interested to carry on a conversation with an intelligent species.

Me too, but at least in the near future we won't get that chance unless they are in the solar system or have technology for interstellar communication.

I suspect you may both get your chance in the next few decades. It'll be an intelligence of our own making, but it certainly won't be us.

 

[Chronos]

This discussion explifies the difficulty in defining intelligence. I can picture an intelligence based purely on chemistry that could be extraordinarly sophisticated. My guess is such creatures might have a vastly different perspective on intelligence and technology.

 

[Chakrapran]

Except that they weren't a good indicator. (As on the Moon, there is also ice, but certainly no life, therefore ice is not a good indicator of life)

Just like Enceladus, organics are not a good indicator of potential habitation.
So I'm not sure why you're saying they are.

Allow me to contradict with you, the bio-molecules are the first step to this study introduced by the most imaginative astronomer of the last century Dr Fred Hoyle. On the basis on his thoughts and H&W study of bacterial transportation through interstellar environment, India already launched a research program under the leadership of Dr J V Narlikar (Student of Fred Hoyle and the co-author of Hoyle-Narlikar gravitational theory)... You can go through this article...

http://www.natureasia.com/en/nindia/article/10.1038/nindia.2009.81

 

[arsenal1607]

I know a lot of people have said in this thread that we have been looking for unusual signs and not found anything yet. Does anybody else not think it's absolutely mind boggling that considering the size of the universe/space and the millions of galaxies and planets there are, that we could be the only little patch that has life?

 

[arsenal1607]

Just to clarify, my point is that i cannot believe for one second that Earth is the only planet in this universe/space that has life, it just seems too unlikely for me.

 

[DaveC426913]

Well, no one's going to fault anyone for their beliefs on the matter.

Unfortunately 'unlikely' is a probability thing. And a sample of one tells us nothing useful.

 

[Zentrails]

I think if there were other intelligent life within the solar system we would have had a definite indication of some sort by now.

It's quite possible that there is intelligent life in our solar system and we just don't have the capability to perceive it. If "God(s)" exists, that would be a good example. Or maybe beings made of dark matter, hive minds, etc. There are a lot of possibilities that I can imagine. I think it is a little arrogant for humans to assume that intelligent beings have to be like us or at least have technology/artifacts similar to ours.

 

[Zentrails]

Your physics is also incorrect. Earth's atmosphere has little to do with radiation. It protects against UV, but its the magnetic field that deflects the majority of dangerous particles, that's what Mars lacks.

A minor point, but actually our atmosphere does protect us from high energy neutrons which are absorbed by nitrogen to form carbon 14. Not sure the flux is much compared to charged particles, but I would call that a form of radiation. Mars' atmosphere is mostly CO2 with little nitrogen. Anyone know what percentage of neutrons actually make it to the surface of Earth? I'm sure it's a much lower number than on Mars.

 

[Zentrails]

It's possible that intelligent aliens could decide to send a highly directional signal to Earth if they already had a good reason to suspect there was a liklihood of the message being received.

Or maybe by accident, say if aliens are using a directed energy source of some sort to power "light sail" like spacecraft ?

 

[rootone]

Or maybe by accident, say if aliens are using a directed energy source of some sort to power "light sail" like spacecraft ?

It's a possibility.
The first detections of pulsars had people wondering for a while.
Those produce highly directional EM beams, although whether or not we by chance happen to intercept one is random of course, no intelligence behind it.

 

[DaveC426913]

It's quite possible that there is intelligent life in our solar system and we just don't have the capability to perceive it. If "God(s)" exists, that would be a good example.

It would not be a good example.
God is, by nature, beyond science. A being detectable only if and how he chooses is beyond the scope of both scientific analysis and this forum.

Or maybe beings made of dark matter, hive minds, etc. There are a lot of possibilities that I can imagine. I think it is a little arrogant for humans to assume that intelligent beings have to be like us or at least have technology/artifacts similar to ours.

No, it would be arrogant to assume creatures don't exist when there's evidence that they might.
But without any conceivable way of detecting them, let alone finding evidence, it would not be an arrogant assumption. It might be a faulty one, but it would not be an arrogant one.

Not sure why having a hive mind would change the equation in any way. Would it mean they would not produce evidence of their civilization - heat signatures, organization, consumption, waste?

 

[Hugh Parker]

rootone wrote: Only Mars could be possibly be survivable given an enclosed habitat and adequate shielding from radiation - Mars' atmosphere doesn't cut it as a radiation shield like Earth's does, and it completely lacks any effective magnetic field. Primitive life might be possible in the subsurface water oceans of some gas giant moons, but there is no evidence at present suggesting that this is so.

Reference https://www.physicsforums.com/threads/what-are-the-ways-we-can-search-for-alien-life.834005/

Well, perhaps the lava tunnels of giant volcanoes are places where life thrived when Mars had water. Deeper sites mean warmer sites. If Mars has lava tunnels, as Earth does, at what range of depths would salty waters be liquid now? What would be the current partial pressures of oxygen and carbon dioxide at those depths?

 

[Monsterboy]

Is it possible to launch Kepler like space telescopes that can orbit the sun in several different planes other than the plane of the orbits of the planets in our solar system ? This way we might be able detect more exoplanets that are undetectable by Kepler today.

 

[Vanadium 50]

Sure. It's more difficult, but it can be done. But why do you think that would help?

 

[Monsterboy]

Sure. It's more difficult, but it can be done. But why do you think that would help?

An exoplanet that orbits in a plane which is inclined such that it does not obstruct the light from the star from reaching the Kepler telescope is undetectable right ? Is it possible to detect those planets by rotating the telescope someway?( i don't think so) can this problem be solved by telescopes orbiting in different planes? now that you asked i feel like it doesn't really help or maybe it does.

 

[DaveC426913]

An exoplanet that orbits in a plane which is inclined such that it does not obstruct the light from the star from reaching the Kepler telescope is undetectable right ? Is it possible to detect those planets by rotating the telescope someway?( i don't think so) can this problem be solved by telescopes orbiting in different planes? now that you asked i feel like it doesn't really help or maybe it does.

The star is 1500 light years away. The farthest we've ever sent a man made object is about 4 light hours.
A telescope launched in a polar orbit (after about ten years travel) would have a better angle of this distant star by about one ten thousandth of a degree.

Nice idea, but no.

 

[Monsterboy]

The star is 1500 light years away.

You are talking about that alien structures thing right ? This may not work in that case but this was actually a general question whether such an orbit might help us detect more number of exoplanets.

The farthest we've ever sent a man made object is about 4 light hours.

Voyager 1 &2 are quite far away than that right ? You are talking about space telescopes?

 

[DaveC426913]

You are talking about that alien structures thing right ? This may not work in that case but this was actually a general question whether such an orbit might help us detect more number of exoplanets.

The nearest star to us is 4 light years away, making an angle of about 1 one-hundredth of a degree.

Voyager 1 &2 are quite far away than that right ? You are talking about space telescopes?

13 light hours. And it took 40 years to get there.