What are the chances that their is another E.T. intelligent lifeform who has visited Earth and has certain ways of observing and watching us without us knowing about it?

And how do you propose that we calculate those odds?

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Conscious reasoning is an attempt to justify the choice after it has been made.

You seem to postulate that which would appear to be impossible to prove.

Best regards,
Dan

As stated, these 'chances' cannot be accurately calculated.

However, I will put forth a set of odds.

50/50. Either they are, or they are not.

nil.

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

I'd say its 33.333... percent. Either they are, they aren't, or they can't count.

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As above, so below

As others have said, it is not possible to actually calculate this, but I think the chances are very, very small.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009
All moderation in purple

They would if they could but they can't so they won't.
They are like that real pretty girl in Algebra 2 that doesn't even know you exist, You imagine what she is really like, but never get to meet her because she moved home.
"Each night the stars put on a show for free,
and if the skies are clear, come see with me."

Here are some words I put together some time ago about how unlikely it is that we have (or had) ET visiting us on planet earth. I hope no one minds the repetition, hopefully it helps illustrate the point:

"There are millions (I forget the number) of stars in our galaxy alone. It is about 30,000 light years to the centre of our galaxy and about 100,000 ly to the far edge of it.

As a race we have only been "projecting" ourselves out into the ether (interstellar space) in the form of radio waves for just a little over 100 years, and with TV probably no more than about 70 years or so. Therefore any radio wave transmissions would only be picked up on the edge of an expanding "sphere of influence" of about 100 ly radius (and travelling outwards at the speed of light). That is, if it is even detectible by then amongst the galactic static. This is so small a proprtion of our galaxy that we MIGHT be detectable within that it would seem extremely unlikely that any potential interstellar travelling ET would have passed through this sphere within the last 100 years. There is just such a vast volume of space to travel through within the confines of our galaxy alone, let alone the whole universe! And this assumes this supposed ET is within our "timeframe" of development. miss us by, say, 1 million years (nothing in the galactic scheme of things) and "he/she/it" would never know we are here.

Then again, even if you asume this supposed ET has a super-fantastic mega-macro optical telescopes our "sphere of influence" for when we would be noticable as some form of intelligent life on earth, probably still only covers about 7000 years (construction of the pyramids, the first cities, roads etc...) , thus the "visible sphere of influence" then stretches out to 7000 light years, still a miniscule volume of the space within just our own galaxy!

If you take either of these scenarios into the context of nearby galaxies, the distances are so immense as not to be worth considering.

Of course, if this ET has developed a super-c method of travel it is fairly likely our technology would be so far behind that we wouldn't be of interest anyway.

Well, that's my two pennyworth, anyway."

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not Eureka! (I found it!) but rather, 'hmm.... that's funny...'
- Isaac Asimov

Are we alone in the Universe? Are we the only intelligent life? Who knows? But the universe is so BIG, it somehow seems such a waste of space if we are ....

And no one has ever explained how any creature, never mind ship, could stand the acceleration to these kinds of extraordinary velocities.... and live.

What sort of acceleration are you talking about? It only takes 1 gee to reach near-c velocities within a couple years. The engineering of providing such prolonged acceleration is certainly a challenge, but the biology is not.

And you have a propulsion scheme that will generate 1 G for 3 years .....
and put the brakes on at the other end?

Well, yes, but that's besides the point. Your claim was that extreme accelerations were involved, but in fact extreme accelerations are not involved.

If you really wanted to provide 1g for 3 years, and then put the brakes on at the other end, then the best method would be to use an "extremely gigantic" long range X-ray laser to push a ribbon laser sail starship.

Your starship consists of a merely "big" long range X-ray laser to decelerate a small sailship. The "big" X-ray laser is a sacrificial drone. It goes sailing off into infinity, discarded forever. Your small sailship is the payload, and it gets decelerated by the laser at your destination.

This is the best way to provide 1g acceleration for 3 years, and then another 1g deceleration for 3 years at the destination.

But it's IMHO a silly thing to do. For much less expense, you could accelerate for less than 1 year and you'd still arrive at your ultimate destination about as quickly. Getting up to near-c velocities is an exercise in ridiculously diminishing returns.

And .... how do you stop?
I know, I have poked this question a number of times..
I suppose my main inquiry should be...... Have you or anyone else ever accelerated anything at 1 G for a long time using anything but rocket propulsion ( excluding gravity slingshot ) and do you have a relevant link to such a scheme? Does it in fact exist?

Best regards,
Dan

I already explained how you stop. The sacrificial laser drone is used to stop. Here are the steps:

1) Extremely gigantic laser is used to accelerate your starship+big laser.

2) Starship+big laser cruises toward the destination

3) Big laser is used to decelerate your starship

4) You arrive at the destination at the end of the deceleration phase, while the big laser goes sailing off into infinity

As for whether I or anyone else (from Earth) has actually done this--obviously not. It's a theoretical propulsion system. Even though it uses near term technology it would be insanely expensive to do (the "big" laser is far more powerful than the biggest laser we've built so far; the "gigantic" laser even more so).

What is your point, anyway?

Look, just because you can't figure out how to do something doesn't mean that no one else can. And just because we humans don't yet have the capability to do something doesn't mean we never will.

And any aliens, if they're out there, are not necessarily limited to the capabilities that we currently have.

Assume LAWKI ET is out there, within 7kLY. Would they know we are here?

via Radio? Nope.

Spectroscopy, yes. They could deduce that there is life here in this solar system by the light spectra which would show Oxygen, Nitrogen, Photosyntehtic processes, Methane, maybe even pollution.

The problem isnt detecting us, its making contact. They may be signalling us, but on some unkown method of communication that is FTL .

Or they started signalling around the time of the dinosaurs, and gave up around the time we invented the spear.

Or, perhaps they've signalled, we've received it, yet our protocols don't allow us to acknowledge it as artificial in origin because it was very brief (something akin to the Wow! signal).

One might say it's ridiculous to think they'd bother at all and broadcast so briefly, and that may be so, but there is precedent. Our very own Arecibo message was broadcast for less than 3 minutes. Would that be enough for an alien astronomer to contact other observatories on his planet to get confirmation?

(Disclaimer: I'm making no claims regarding the Wow! signal. Just pointing out that if we were to receive something like the Arecibo message, our own SETI protocols would not allow us to acknowledge it as being artificial in origin.)

I suppose that was at least part of the point I was trying to make. Even if ET did detect us by being within the 7000ly 'sphere' would they be interested if they saw earth development at, say, 3000 years ago?

Or, should any such ET have passed 'nearby' to earth, but missed us by perhaps 1 million years (a mere moment in cosmic terms) they would (probably/possibly) not see much to interest them, except perhaps early man in hunter/gatherer mode.

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The most exciting phrase to hear in science, the one that heralds new discoveries, is not Eureka! (I found it!) but rather, 'hmm.... that's funny...'
- Isaac Asimov

Are we alone in the Universe? Are we the only intelligent life? Who knows? But the universe is so BIG, it somehow seems such a waste of space if we are ....

I would suggest that the odds of the universe teeming with life is very good, simply because its so big and full of so much stuff, and the odds of ever meeting this other life is very bad simply because the universe is so big with so much stuff.

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ooops..... wrong forum!!!

It depends, but I'd say that if they have the technology to detect us, it's safe to say they have enough scientific curiosity to be interested. What actions might result from that interest is hard to say. Even amongst humans there would be massive debate if we confirmed life on another planet. Some would want to begin constructing spacecraft immediately, while others seem to believe that even sending a radio signal is too risky.

Or, we were of interest, but as a subject of study rather than as someone to introduce themselves to.

When we study chimpanzees we don't tap them on the shoulder and try to teach them calculus, we keep our distance and observe their natural behavior. But we do still find them interesting enough to study.

Then again, maybe life is so common that they just said "Oh, there's another one", jotted our coordinates down on their list, and moved right along.

One has to consider that even if et came by, it could have happened
650,000 years ago when nothing was happening. Imagine a survey crew dropping down just after Yellowstone blew it's stack, acid rain and winter kicking in strong, plants dead etc etc. Well, they'd be gone. Time has no reference to interstellar travel. It has no reference to our system.
Why should they have to come durring the brief time we have tooled around with electromagnetic waves? What is 100 years in the reflection of
infinity? There is your odds. The odds are compounded by the time frame.
Best regards,
Dan

Well, they would have seen some pretty interesting proto-humans (homo erectus) hanging around in various geographically dispersed regions. Interesting times for some.

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Conscious reasoning is an attempt to justify the choice after it has been made.

Yes,
The time frame I feel is the largest issue. The time frame of modern human existence is so minuscule relative to the time frame of the existence of the observable universe. When then you consider the time frame of human technological transmission at lets say a little over 100 yrs (a nano second compared to the cosmic ages we encounter) then it seems almost impossible that we would ever be detected, certainly for at least a few millennia to come.

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ooops..... wrong forum!!!

Only if you assume that radio is the only means through which we could be detected. If our life-capable atmosphere were detected through spectroscopy, then the window of opportunity is considerably larger than 100 years.

It wouldn't necessarily give away that there was life here, only that there could be. But, for a civilization looking for other life it would probably be enough to say "Hey, that one's worth checking out". Of course, "checking us out" would probably just amount to more thorough telescopic observation.

Simple optical spectrographic detection amoungst billions of star systems
has to be considered remote. Spill a 5 pound bag of sugar and pick out a grain..... the grain of sugar....hmmmm. And that's good odds. More like a 3 cubic yard bucket.

Maybe those are the odds if you assume that the alien civilization only looks at one star system. But why would they stop at just one star system? We haven't.

It also implies the assumption that there's only one other civilization looking.

This would turn into a Drake Equation scenario, where a whole assortment of assumptions would have to be made.

On top of that, some of them would probably have to relate to the psychology of the visitors, which is the start of just one slippery slope - how do you determine the way these alien organisms think?

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The left hand knows full well what the right hand is doing, but quietly ignores it.

Thats not a good analogy. Its not as if we are picking a random star and then looking there. That would be ridiculous.

Kepler is currently searching over 170k stars for Earthlike planets. What they do first is find an area of the sky which is well withing the Galactic Habitable Zone (GHZ) which allows a constant view for 3-4 years. Then it picks out Stars that are like ours, main sequence, and old enough to have formed planets. Then, it weeds out those that are trinaries or otherwise unstable. Then, it has whittled down these candidates to about 100k, it stares at them for 3.5 to 5 years and records the periodicity of drops in the light which indicate a planet passing. From the drop in light and periodicity, we determine approximate size, orbit, and other parameters. Then, we can determine of liquid water is possible. Finally, through spectroscopy, we could determine if there are the basics there (Carbon, Oxygen, Nitrogen, as well as Methane, and hopefully, photosynthetic processes.

It is predicted that within 15 years, we will find direct evidence for life on an exoplanet using this method.

I would have to agree, every assumption in turn leads to more assumed determining factors to apply in any mathematical calculation. The drake equation hits on these basic fundamental assumptions to give us a rough idea. But i would suggest its far from accurate, just an educated guess.

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ooops..... wrong forum!!!