If We Can't Detect Alien Life Is It Possible It Could Detect Us?

[Mintaka]

Just your personal opinion.

 

Is it possible other civiliations have learned how to travel close to or even exceed speed of light space travel?

 

If so, if they are our only hope of survival, can we assume that, being technolgically advanced, they will also be benign?

 

Do you like the idea of aliens discovering us? Or does it scare you?

[sanctus]

If they are benign, then I think it would be super-cool and interesting.

 

If they are not, it will have the positive effect that humanity will be unified for once ;p

 

As to your first question, it is not possible to prove something is not possible (which is a bit contradicting said in this way :-)), because to prove an impossibility one needs complete knowledge of everything...

[Mintaka]

Thanks Sanctus. I personally hope they hurry up and get here fast.

 

They are probably our only hope for survival.

[CraigD]

If We Can't Detect Alien Life Is It Possible It Could Detect Us?

Certainly it’s possible.

 

We’re rapidly getting better at detecting extrasolar planets, including characteristics that indicate the likely presence of biological life. Despite recent history of setbacks and cancelations, I also expect robotic space missions to extraterrestrial bodies in our solar system with some likelihood of biological life, such as Europa, may discover alien biological life.

 

So I think it likely that within the next few decades, we’ll have strong evidence and vigorous scientific study of alien life.

 

However, what most people, and I think you in this thread, Mintaka, mean when they say “alien life”, is not the ecosystem of an extraterrestrial moon or planet (eg. This:

) but something like this:

- intelligent aliens able to visit Earth and communicate with us. Though there are a plethora of scientific reasons why life like this should be much rarer than life that can’t travel between planets and stars, biologically living aliens traveling in spaceships, or, more likely, I think, their robotic probes, could be much more difficult to detect than the presence of ecosystems on their moon or planets.

 

For these reasons, I think it’s quite reasonable to postulate that intelligent aliens might have detected our presence on Earth. It’s certain (unless you’re a believer in “Area 51” type conspiracy tales) that we’ve not detected them.

 

Just your personal opinion.

 

Is it possible other civiliations have learned how to travel close to or even exceed speed of light space travel?

Personally, I don’t think any technology can permit faster than lightspeed travel. There are many technical reasons that make traveling close to the speed of light more expensive than the travel time saved is worth. We’ve discussed these at length in various threads, so I won’t rehash them here.

 

For these reasons, I think that visitors from other star systems are most likely to arrive by spacecraft traveling less than half the speed of light, and more likely be robotic spacecraft than manned ones. An fictional example of what I – and the late Arthur C, Clarke – think is a reasonable alien space probe is “Starglider”, from his 1979 novel The Fountains of Paradise (more a stand-alone short story embedded in the novel than part of its main plot). In this novel, we carry on a long, mostly open exchange of information with the artificially intelligent computer on this slow-traveling interstellar spacecraft as it passes through the solar system, which transmits the information back to its many lightyear distant planet of origin, “Starholme”, learning that it has been traveling for 60,000 years, and discovered 174 planets inhabited by people similar in technological level to us. People more interested in extraterrestrial life than space engineering might read this 32 year old Hugo and Nebula award winning novel just for its Starglider/Starholme chapters.

 

If so, if they are our only hope of survival, can we assume that, being technolgically advanced, they will also be benign?

Let me reflect the question back as the question “About nations and cultures on Earth, can we assume that being technologically advanced means they will also be benign?”

 

Though this question has plenty of room for debate, I think it’s safe to answer that while technological sophistication may suggest cultural kindness, it doesn’t guarantee it. I can see no reason to believe this is doesn’t apply off Earth as well as on.

 

I can imagine a chilling logic that concludes that technologically and socially advanced alien would be compelled, after studying our biology, psychology, and history, to either exterminate us, or imprison us on our planet: Despite our facility for rational thought and planning, we are in practice an explosively reproducing species, expanding into nearly every survivable habitat and increasing our population to consume all available resources, while relentlessly eradicates all competing species. To these advanced aliens, we would appear pathologically dangerous, especially as we are potentially intelligent enough to learn their technology, and use it to travel to and colonize other planets. In order to save the galaxy, it would be necessary to prevent us from expanding into it by whatever means necessary.

 

Do you like the idea of aliens discovering us? Or does it scare you?

I like it, and it scares me. I can think of no other rational way to feel about the unknown.

[Deepwater6]

Light speed would still take many many years for some of these neighbors to get here. Is it possible for aliens to jump into our dimension from theirs? If we can detect them and they do exist how hard would it be if at all?

[CraigD]

Light speed would still take many many years for some of these neighbors to get here.

If you had a spaceship that could travel close to the speed of light (according to best current theory, reaching or exceeding lightspeed is impossible) – no easy task for reasons too numerous and detailed to go into here – you could travel a light-year of distance in much less than a year of time, due to relativistic time dilation. For example, at 0.995 c, your travel time for 10 ly distance would be [math]\frac{10 \,\mbox{ly}}{c\,\sqrt{1-0.995^2}} \dot= 1 \,\mbox{y}[/math], about 1 year. The “universal speed limit” of c imposed by the theory of special relativity doesn’t seem as restrictive if you understand the essentials of the theory.

 

Is it possible for aliens to jump into our dimension from theirs?

The sort of aliens I’ve been describing, and that astronomers and exobiologists speculate about and search for, don’t exist in “other dimensions”, but in our usual 3 of space and 1 of time. No special “dimension jumping” technology is needed for living beings from different solar systems to get together, just spaceflight technology sufficient to travel the great distances between them, and astronomy good enough to find neighbors to visit.

 

Various “shortcut” technologies – traversable wormholes and the like – would be nifty, but our current physics can only begin to speculate about what this might be like, just barely hint at a possible technology for building it, and not state with much certainty if it’s even possible or not. All of these speculative technologies raise trouble issues about causality, such as the paradox of going into your own past and messing with yourself so you don’t in your future go into your past, as they’re all not only shortcuts in space, but in time, too.

 

We can’t entirely rule out the possibility of visits from beings from entirely different universes, but the basic physics and technology involved, if it’s possible at all is so far beyond our current understanding, that we can’t do more than wildly speculate about it – it’s more speculative fiction than science.

[Mintaka]

Really brilliant replies Craig, thank you. Very interesting.

 

I'm ineterested when you say " completely different universes". Does this mean you lean towards the idea of other universes created by other big bangs?

 

It must be hard for astronomers and mathematicians who know their subject to come up against 'unknowables' , areas their understanding can't reach..?

 

It must be a humbling experience to study such areas...My mind is blown just by looking at the night sky. We talked about the Milky Way the size of a dinner plate....

 

but it would take us millions of years at current speeds even to reach the edge of this plate, (I think). Sorry to sound like a hippy but coming to this forum and getting

 

the benefit of you guys knowledge has opened my eyes a lot and made me see things in a new way....Maybe it sounds weird but I came to live by the sea 6 months ago

 

and when I see the point of light crossing the ocean slowly at night, I imagine a point of light travelling slowly across space,...when I see insects I don't kill them anymore

 

because if you zoom down to their level they are much bigger than we are in relation to our galaxy - I suppose im trying to say that Ive started to think in a 'relative' way about everthing,

 

and I thank all the helpful people in here for the time they give to explain to idle dreamers like myself.

 

 

 

If you had a spaceship that could travel close to the speed of light (according to best current theory, reaching or exceeding lightspeed is impossible) – no easy task for reasons too numerous and detailed to go into here – you could travel a light-year of distance in much less than a year of time, due to relativistic time dilation. For example, at 0.995 c, your travel time for 10 ly distance would be [math]\frac{10 \,\mbox{ly}}{c\,\sqrt{1-0.995^2}} \dot= 1 \,\mbox{y}[/math], about 1 year. The “universal speed limit” of c imposed by the theory of special relativity doesn’t seem as restrictive if you understand the essentials of the theory.

 

 

The sort of aliens I’ve been describing, and that astronomers and exobiologists speculate about and search for, don’t exist in “other dimensions”, but in our usual 3 of space and 1 of time. No special “dimension jumping” technology is needed for living beings from different solar systems to get together, just spaceflight technology sufficient to travel the great distances between them, and astronomy good enough to find neighbors to visit.

 

Various “shortcut” technologies – traversable wormholes and the like – would be nifty, but our current physics can only begin to speculate about what this might be like, just barely hint at a possible technology for building it, and not state with much certainty if it’s even possible or not. All of these speculative technologies raise trouble issues about causality, such as the paradox of going into your own past and messing with yourself so you don’t in your future go into your past, as they’re all not only shortcuts in space, but in time, too.

 

We can’t entirely rule out the possibility of visits from beings from entirely different universes, but the basic physics and technology involved, if it’s possible at all is so far beyond our current understanding, that we can’t do more than wildly speculate about it – it’s more speculative fiction than science.

[Moontanman]

I think they are already here, (inexplicable UFO sightings are the evidence of this)living in orbiting space habitats, no use for planets slowly moving across the Galaxy as they colonize very star with enough material in orbit around it to make new space habitats. Their only interest in planets would be when they found life and or intelligence. An elite few might want to study our rise to civilization but most would ignore us and go on about their business. It's possible they might study us to find the best way to manipulate us if the need arises when we go out into space. It would be fairly easy to cover their presence in our solar system and still influence us, some of our religions could be attempts by the aliens to see how easily it would be to manipulate us if we became a problem.

[Deepwater6]

That's an interesting theory Moontanman about using different religions to influence us. I have heard the claim that when Moses went up the mountain to get the ten commandments he was really visited by aliens. If a spaceship came down in that period of time I would probably think they were Gods myself.

[Moontanman]

That's an interesting theory Moontanman about using different religions to influence us. I have heard the claim that when Moses went up the mountain to get the ten commandments he was really visited by aliens. If a spaceship came down in that period of time I would probably think they were Gods myself.

 

 

It's just a idea, nothing what so ever to back it up, I used to debate my sons about how and why aliens would be here any why do they act so oddly if they are real. I honestly do think that UFOs were never given the "scientific investigation" the US Air Force claimed and the Air force's own scientist J. Allen Hynek made the same assertion after working for the air force for many years. He broke with the Air force and spent the rest of his life studying UFOs, his own conclusions were pretty far out but he thought the evidence supported the "not of this earth" idea.

 

For the OP it should be pointed out that early estimates of how the Earth's radio signals could be detected as a sphere emanating from the earth to the distance of about 100 light years or so is misleading. It's unlikely our "leaking signals" signals could even be detected at the nearest star due to interference from interstellar gas and dust. The original estimate of how far away we could detect aliens ignored these problems and assumed the aliens would be intentionally broadcasting a very strong signal not simple "leaking" of signals from their planet.

[belovelife]

i think advanced species have many possibilities, like one similar to an ant, hard shell, scent communication, sounds good for a planet without an atmoshere

or a giant squid that developed magnesium fire, who knows

 

but i think that if they did develop interplanetary travel, it would be based on bending space time, and if they were smart enought, go (fishing)

with this tecnology while another species is asleep, while they are in a "fish bowl" of air, wake them up treat it like a dream, send them home, and then

were they able to remember the dream or not

 

probly a huge series of tests and mazes, with the goal of understanding their thought process, ( in the case of the ant like species)

since to them communication is with scent, but writing data may be similar to us, math, physics, etc.

also in this case, being in an atmoshere might be like us in water, where we can go in, but we cannot breath,

or mabe they just cannot handle the weight of our atmoshere

 

so many varyables

 

where the giant squid that made it to space from somwhere like europa, well, traveling in a ship might not be that much different

than living on their planet,

 

either way, i would say that any intelligent species that could travel throught the stars would hold life as a miricle, and want to learn about and experience as much as they could

since there is more matter in the universe then we can even comprehend, resources would not be worth battle, but arts and ideas would hold value

 

just imagine cracking through ice of europa, pulling out a fish bowl of an ant species that lives underwater, and builds cities, then trying to communicate with them