contracycle

IIRC, they blew off 15-odd km/s getting out of the solar gravity well, so their actual velocity relative to sol is about 1km/s now.

contracycle

On telescopes.

I have heard we could hang a monstrously large telescope somewhere out by the orbit of jupiter, and use the suns gravity well as a lens. That system was described as being big enough to resolve clouds on planets in remote systems... how remote I don;t recall exactly, but we are talking about a telescope whos length is measure in AU.

contracycle

We started listening to the universe the very first time we built a crystal radio set. Radio has been a tremendously powerful tool which has permitted us to learn an immense amount about our non-proximate surroundings.

It is not just the case that *a* technical specieis could have popped up, broadcast past us, and disapeared or developed past radio... but there should be batches of initial signals from multiple sources at multiple distances. We are talking about multiple stones falling into a pond - there shpuold be multiple ripples arriving at different times at any given point in the pond.

Shadowy Man

I don't know the exact number, but if 1300 is correct, that it is a very small number in this game.

auto-da-fe

Agreed. That would be like picking up a small bit of sand and making assumptions about every sand grain on the planet based on what is in your hand.

I don't honestly think that anything we are currently doing is likely to produce meaningfull results. The scales are just much too large. Like so many things throuhout history, I believe if this is going to be resolved it will be done so almost by accident. That is assuming, of course, that we aren't going to be proactively contacted from them (ET, ALF, et al). Unfortunatly, I think this is actually are biggest chance to find someone/thing out there. To have them contact us first (of course, some would say they already have).

I am intrigued about your solar gravity well telescope contra. Do you have any links on a paper or discussion about this? Really, IMO, this would be the most effective way of doing things.

It is obvious to me, that unless someone/thing contacts us as mentioned above, the only thing my generation, and probably many more to come, can hope for, is to discover microbes, and other similar liife. Bacteria, amino acids, perhaps even a form of DNA, but nothing like the intelligent life we all would love to see. That is not to say though, that there isn't anything to do in space. Even w/o finding any other form of life, it is still a worthy mission to try to get to Mars, inhabite (permanently) the moon, serach some of the moons of Jupiter like Europa and Io, and any number of other missions, all of which would be worthy endeavors.

Anyone else hear about the ideas floating around to turn Mars back into an Earth like planet with an atmosphere, water, and the whole nine yards? By doing sections at a time, it could be done, but it would take something like a hundred generations to achieve.

auto-da-fe

Would this not be making several assumptions that are improbable at best?

First we would have to assume that several different types of "intelligent life" have developed in several different areas of the universe. Second we would have to assume that all types of life will eventually discover, and use, radio. Third, we have to assume that they have done so in a time line similar to ours, and there signal didn't pass us up, say, 4 million years ago. Fourth, we have to have our antennae pointed in the right direction at the right time. Fifth, that we are listening to the right frequency. Sixth, that we would even be able to recognize an alien communication. Seventh,.... well you get the point.

There are just way, way too many variables involved for me to have much hope of finding life via radio waves.

Arken

Another unfortunate problem that SETI has, and one which probably cannot be resolved is that it looks for signals in the Microwave bands only. Why? Because humans use the other bands exstensively creating so much noise that we can't even begin to hope for filtering it all out while the microwave bands remain relatively quiet.

Since we don't use them that much, it is conceivable that neither do any ETs.

contracycle

I probably read it in Scientific American. I can do some digging, but the principle is so simple it doesn't seem very tendentious to me. It arose from obeservations of stellar paralax seen during eclipses, as I recall.

Well, granted. But thats why I posted the Drake equation itself; we could thumbsuck our own variables and see how many we think the ballpark should be. Drakes initial figures produced 10,000 technical, radio using species in our galaxy alive today. That shouldn't be so hard to spot.

I know very well the drake equation is Not Science; its a Back Of The Envelope calculation, at best. But I find the assumption that the Great Silence is normal even harder to swallow; it makes us too special, smacks to much of the anthropic principle.

If we find life on Europa, or anywhere in the solar system that cannot be traced to some sort of solar panspermia model, then we will have independant occurrences of life, and the probabilities giving big numbers out of the DE get more likely. I tend to think that we might already have parallel ecosystems, our own and that based on Black Smoker colonies. If the cetaceans turn out to be sapient, we'll have two intelligent beings on one planet; how probable is it then that it never happens anywhere else?

I'm well aware we can't say anything meaningfully serious about this all, as yet. I would, however, defend SETI as a worthy project, and possibly one of immense importance. Yes, sure, the vast majority of biomass on the planet is dumb as a stone - but against that, some handful or so of species display intellection of a high order, if not perhaps as high as ours. I do think life is a naturally emergent property of the universe, and that intelligence is a naturally emergent property of life - the question "where is everybody" bugs me quite a lot.

Arken wrote:
Its easily conceivable that any given ET specieis might not. But for this to explain the Paradox, every single technical species would have to make the same decision. Thats much more of an assumption than the inputs to Drakes equation.

Arken

contracycle,

I don't know enough about telecommunications to know why we don't use microwaves... could it be that there is a good reason that we tend to stay away from those frequencies- a reason that most other advanced civilizations would choose as well? For example, perhaps those frequencies require a lot more power for clarity and range...

contracycle

Oh yes. Different bands of the electromagnetic spectrum have different degrees of naturally occurring interference, so some are clearly and objectively better than others. I understand that a frequency termed the watering hole, partly because it is stopped by water vapour and hence is totally invisible to ground-based 'scopes, and partly becuase thats where'd expect to see people gathering around, is the optimum frequency for long distance electromagnetic transmissions. Hubble was meant to operate in this frequency, but doesn't because of the bent lens. Bugger.

However the point of my objection was that while a sound reason for any particular non-advance can be provided, its difficult to explain why the limitation should operate consistently across what we THINK should be a large number of attempts.