Is SETI worth it?

[vlix]

There "could" be. The Drake Equation has a number of parameters that we can only guess at. But putting numbers in towards the optimistic end of reasonable does give that result.

Exactly. But i would say that even when using rather pessimistic values for the various parameters, the chances of there being intelligent alien life trying to contact us, are still quite a bit bigger than the chances of God parting the clouds

 

[AtheistArchon]

- The way I see it, there are two opposing sides to this issue.

- The first thing to consider is that we have a tight, coherent bundle of knowledge and science that says "wow, we know a lot about physics and radio waves and light, and communicating at FTL speeds just doesn't appear to be possible". For a majority of skeptics (here anyway, IMO), myself included, we listen to this voice quite often. It's a voice that says hey, this kinda sucks, but it's what we're seeing. That's the nature of skepticism and freethought after all.

- Then again, there's another thing to consider: immediately preceeding every great scientific breakthrough, there has been the same above voice. And keep in mind, we're newborns in the universe. This is the kind of thing I like to say I have faith in... that we'll continue to advance and break barriers. That doesn't mean I'm telling anyone it's the truth, or that my faith means it automatically has to happen. My faith is hope. And I hope I'm right.

 

[drkitten]

I would disagree, I suspect we become more and more visible in the radio spectrum as time goes on. Unless we seriously misunderstand the laws of physics, there really isn't a realistic basis for a technology that could replace it.
/B]

Well, I'm really glad that I'm living in the early 21st century, where the possibility of us seriously misunderstanding the laws of physics has finally been eliminated. It's so nice to know that we're in the final lap of this rat race we call "science" and we finally have the Answers.

As it happens, you're already wrong. We are becoming less and less visible in the radio spectrum, because broadcast technology is extremely wasteful of power. The amount of data carried invisibly over non-broadcast media (like cable TV) is already substantially greater than the amount sent over the air, and most of the major media companies.

Also, the better our encoding and compression technology becomes, the closer our signals become to random noise, which is essentially invisible. In another hundred years, we'll probably look (to today's SETI) just like a a solar flare.....

 

[scotth]

As it happens, you're already wrong. We are becoming less and less visible in the radio spectrum, because broadcast technology is extremely wasteful of power. The amount of data carried invisibly over non-broadcast media (like cable TV) is already substantially greater than the amount sent over the air, and most of the major media companies.

Not really, the stuff that would be most easily detectable are not TV stations. Radars and such would be far easier to detect at a distance.

And even if cable carries more than what is carried over the air, that doesn't mean that what is carried over the air has decreased. It just means the total amount of infomation broadcast has increased.

 

[shecky]

Because between SETI and a big mac, SETI wins.

OK, OK. So how 'bout between SETI and a really good pizza?

Mmmm.... Pizza...

 

[drkitten]

Not really, the stuff that would be most easily detectable are not TV stations. Radars and such would be far easier to detect at a distance.

No. Radar transmissions are usually relatively low powered compared to media transmissions (since the average area you need to watch via radar is much smaller than the average TV/radio station's footprint).

 

[scotth]

No. Radar transmissions are usually relatively low powered compared to media transmissions (since the average area you need to watch via radar is much smaller than the average TV/radio station's footprint).

I was a radar tech for 8 years and I can tell you categorically.... you are flat wrong on that statement.

The output power of radars are typically MUCH higher than for media transmission, and further they are directional. This would make them detectable at a much greater range with the same output power.

For air search, a low power radar starts at about 100kW. I am not aware of any TV or radio station broadcasting at greater than 100kW.

And there are plenty of 1MW and greater radars. I've worked on a 2.3MW radar. (AN/TPS-32)

 

[UnTrickaBLe]

OF COURSE it's worth it. it is the most logical and cost-effective search for ET life. If you have any doubts, read some of Carl Sagan's non-fiction flourishes in CONTACT.

 

[Batman Jr.]

I think people missed my post about why "more complicated" technology may not necessarily make implicit the presence of "less complicated" technology.

Originally posted by Rob Lister

Then again, they might use telepathic communication. I'm not sure what such a discovery might mean for JREF.

If, however, they used nutrino modulation, is it not reasonable that they would have progressed to that technology through others, just as we have progressed through smoke signals to laterns, electrical, CW, AM, FM VHF, microwave and now to fiber?

The problem as I see it is that (even) we have only been visible in the radio spectrum for a hundred or so years. In another hundred or so we will likely again be invisible (assuming we don't remain technologically stagnent.

Perhaps the 'nutrino modulation' comment has more weight than its author knows.

 

[alfaniner]

Then again, they might use telepathic communication. I'm not sure what such a discovery might mean for JREF.
...

So, if an alien proves it can communicate telepathically, would it win JREF's Million Dollar Prize?

And what would it do with it?

 

[Rob Lister]

Not really, the stuff that would be most easily detectable are not TV stations. Radars and such would be far easier to detect at a distance.

1) What is it you think 'radar' sounds like once you detect it?

2) Why do you think 'radar' will still be in use 100 years from now?

And even if cable carries more than what is carried over the air, that doesn't mean that what is carried over the air has decreased. It just means the total amount of infomation broadcast has increased.

RF pollution has increased, greatly, but it has also become mostly, and intentionally, unintelligible.

 

[scotth]

I think people missed my post about why "more complicated" technology may not necessarily make implicit the presence of "less complicated" technology.

I was trying to point out that RF communication would be expected, more advanced technology musings to the contrary.

Neutrino communications (for example) is pretty much a fantasy idea of SciFi to sound advanced and high tech. Its a pretty rediculous idea, actually. Neutrinos would have to be one of the worst possible choices of things to attempt communications with.

There are 4 forces that can be used to communicate over a distance with. Gravity, EM, strong nuclear, weak nuclear.

EM is the obvious and useful choice. We use it because its properties lend themselves to the task. None of the others do, not even close.

Unless we discover something completely unexpected that would provide for something like "sub-space" communications, ala Star Trek, the EM spectrum is the place to look.

 

[scotth]

1) What is it you think 'radar' sounds like once you detect it?

2) Why do you think 'radar' will still be in use 100 years from now?




RF pollution has increased, greatly, but it has also become mostly, and intentionally, unintelligible.

1) Not really a useful way to phrase the question, really... but hopefully this will answer you. If you are just trying to detect (not communicate with) another technological civilization, you just need to detect a clearly artificial radio signal. Radar signals would stand out as artifical very clearly. They wouldn't "sound" like anything though. It will just look like a high power, nearly monochromatic RF source, with very minimal, but clearly artificial encoding. Generally radar signals are encoded just enough to make it clear that you got your own signal back. Therefore they look very deliberately artifical.

2) I can't imagine that we won't be interested in tracking aircraft, spacecraft, weather, or potential incoming missles in the future. We bounce radar off of other planets as well, for that matter, but not on a regular basis.

The signal does not need to be understood or be decoded to realize you have detected an RF signal.

 

[Rob Lister]

Unless we discover something completely unexpected that would provide for something like "sub-space" communications, ala Star Trek, the EM spectrum is the place to look.

As has been pointed out by others, you are correct. But you are correct for the wrong reason. We have to look at the EM spectrum because that is currently the only thing we understand well enough. I don't see why that's going to be the case in a hundred years but even if it is, we are already trending to lower power transmission with higher sensitity receivers and completely garbled content.

 

[Rob Lister]

1) Not really a useful way to phrase the question, really... but hopefully this will answer you. If you are just trying to detect (not communicate with) another technological civilization, you just need to detect a clearly artificial radio signal. Radar signals would stand out as artifical very clearly. They wouldn't "sound" like anything though. It will just look like a high power, nearly monochromatic RF source, with very minimal, but clearly artificial encoding. Generally radar signals are encoded just enough to make it clear that you got your own signal back. Therefore they look very deliberately artifical.

Okay, what is it you think a radar signal 'looks' like. For example, what does the output of a phased array transmitter 'look' like at a distance of ten or twenty lightyears? A hundred? A thousand?

2) I can't imagine that we won't be interested in tracking aircraft, spacecraft, weather, or potential incoming missles in the future. We bounce radar off of other planets as well, for that matter, but not on a regular basis.

Why do you think that we'll use radar to track such things? Have you no faith?

[/quote]The signal does not need to be understood or be decoded to realize you have detected an RF signal. [/QUOTE]

Why not? Background RF is fairly common.

 

[scotth]

Okay, what is it you think a radar signal 'looks' like. For example, what does the output of a phased array transmitter 'look' like at a distance of ten or twenty lightyears? A hundred? A thousand?

Quoting myself.

It will just look like a high power, nearly monochromatic RF source, with very minimal, but clearly artificial encoding. Generally radar signals are encoded just enough to make it clear that you got your own signal back. Therefore they look very deliberately artifical.

Why do you think that we'll use radar to track such things? Have you no faith?

Faith in what? I have faith that radar will improve in the intervening years. The phsyics of the situation dictate much of what the solution is gonna look like.

Why not? Background RF is fairly common.

Background RF is not systematically and intelligently modulated or encoded. You do not need to be able to understand the data, to plainly see that data is being carried on RF.

 

[Rob Lister]

Quoting myself.


Faith in what? I have faith that radar will improve in the intervening years. The phsyics of the situation dictate much of what the solution is gonna look like.

So physics, as we understand it today, dictates tomorrow's solution? That's just the part I don't get. That and...

Background RF is not systematically and intelligently modulated or encoded. You do not need to be able to understand the data, to plainly see that data is being carried on RF.

If you think about it, your logic is circular. Still, would you consider the output of a pulsar star to be at least systematic? Would you consider it more or less systematic than the output of a phased array radar?

 

[scotth]

As has been pointed out by others, you are correct. But you are correct for the wrong reason. We have to look at the EM spectrum because that is currently the only thing we understand well enough. I don't see why that's going to be the case in a hundred years but even if it is, we are already trending to lower power transmission with higher sensitity receivers and completely garbled content.

I don't think you understand what exactly we (as humans) understand concerning physics, and conversely what we don't yet understand.

There is an implication in your posts, that we are likely to make some fundemental discoveries that would enable entirely new forms of communication at a distance. You are probably thinking about the history of science and the revolutions brought about by Newton, Maxwell, and Einstein during the past. And we must be conceited to think that this won't continue to happen. There is a difference, then and now aren't equivilent.

In the past there were always a stack of observed physical phenomena that we could not adequately explain or explain at all. Today, there are no observations that appear to be outside of explanation with the known forces and particles. What are the problems of today's physics? Getting relativity and QM into one theory.... understanding why there are 4 fundemental forces, why there are 3 spatial dimension, why there are 3 families of fundemental particals?

Resolving any of these outstanding issues wouldn't reasonably lead to some new method of communication that didn't require EM.

 

[scotth]

If you think about it, your logic is circular. Still, would you consider the output of a pulsar star to be at least systematic? Would you consider it more or less systematic than the output of a phased array radar?

Really, go study RF theory and modulation. That is what you need to follow this.

A pulsar (other than blinking on and off from the observers point of view, at a regular interval) is not modulated or encoded in any way.

Typical radar signal features:

1) Changing transmit frequency mid pulse
2) Typically phase modulated
3) Very narrow band

The 3rd feature isn't especially useful, but the first two would make it look very artificial.

Putting data on a carrier is called modulation. Even with no idea what the data is, or how it is encoded, communication and radar signals look "made".

 

[drkitten]

There are 4 forces that can be used to communicate over a distance with. Gravity, EM, strong nuclear, weak nuclear.

EM is the obvious and useful choice. We use it because its properties lend themselves to the task. None of the others do, not even close.

Why do you assume that we need to use forces to communicate at a distance? I communicate with particles --- well, they're usually called "pieces of paper" --- all the time. Similarly, much of my communication is done with much smaller particles called "electrons." I don't see any particular reason that I can use electrons for communications and not (assuming sufficiently advanced technology) mesons, neutrinos, yadda yadda.

More to the point --- communicating via EM specifically does not imply that the EM is detectable as a communication at a distance. For example, I can use a laser (which is, of course, an EM signal) to communicate between two points without having anyone else pick up the beam outside of the direct line-of-sight, since a laser beam is directional. As another example, since the bandwidth of any channel is limited, I will probably want to compress data before I send it --- a really good compression system will yield data that's indistinguishable from noise.

Our hypothetical aliens may be communicating using a directional, highly compressed signal carried by a stream of high-speed mesons. SETI would never find that.