The Greatest Question:

So how about you clarifying what's the wrong direction? You're still having a problem understanding how these signals are transmitted. Let's ask a simple question. Do you really think that the Russian dude and Stephen Hawking would be involved in this project if there's a likelihood that the signals would be transmitted in the wrong direction? Whatever that means. BTW you've already had this explained to you in a different thread where you never got it. For communicating over an interstellar journey this is the way to go.
http://science.nasa.gov/science-news/science-at-nasa/2014/18jun_opals/
The following is what interstellar communication between earth and the accelerating relativistic rocket would deal with.
https://en.m.wikipedia.org/wiki/Rindler_coordinates#The_Rindler_horizon

 

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One point worth noting, especially in view of Global Warming and proliferation of nuclear ICBMs, not to mention lethal biological weapons that spread - are easily transmitted (airborn contagion) is that we have no reason to believe the "advanced life from" (defined as having discovered most of these) on earth (and else where) can avoid extinction for 500 years - I.e. if we wanted to communicate with ET even only 250 L years way, that may not be possible as one or both the life forms may not exist for 500+ Ly.

Certainly there is very low probability both would have reached the "advanced state" at the same time. IE, even if the ETs remained advanced for 100,000 years and beamed signals to earth (et al), the dinosaurs did not notice them.

 

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Of course

But we all know the concept of the question is moot.

 

From BruceP Post # 21

Let us consider some calculations for a directed signal.

The sine of an angle in radians = x - x^3 -x^5. . . . . . .For small angles, only the first term is significant.

There are 2Pi radians in 360 degrees.

Consider a circle cut into 3600 pie slices. The central angle for each slice would be Pi/1800 radians, an angle which would be hard to distinguish from zero. Call this angle A.

Sin(A) = Pi/1800 Radians, neglecting the higher order terms.

Sin(A) = .001745329

Consider The angle A to be an error in direction for a directed signal & let us calculate the effect of that error for the distance from Proxima Centauri to Earth, which is a bit more than 4 light years. The following uses 4 light years instead of the slightly greater actual value.

Light travels 186,282 miles per second.

Distance = 4*186282*3600*24*365.24

Distance = 2.35138E13
Distance*sin(A) = 41,039,338,273

The above indicates that a very slight error in the direction of a signal would result in missing the intended target 4 light years away by circa 41 billion miles.

The closest star to us is Proxima Centauri, a bit over 4 light years from us.

The above calculations assume a stationary transmitter & a stationary receiver. Our orbital velocity around Sol is (I think) 67,000 miles per hour & a planet orbiting Proxima Centauri would have a similar velocity, making the problem more difficult.

The above indicates that it would our current technology could not send a directed signal to a planet orbiting Proxima Centauri. I doubt that future technology could do it. Yet SETI is allegedly hoping to receive a signal from some ET technological culture which is likely to be more than 4 light years away & is unlikely to know that we exist.

The SETI folks are not dumber than I am. They should be able to do the above calculations. What are their motives? I suggest one of the following.

A publish or perish motive common in academic contexts with those with the money perhaps not knowledgeable enough to be aware of the above.

A desire to have funding for equipment which is interesting to use for various purposes.

 

No, not at all. Like I said, probably the greatest question anyone on earth would have answered. Even if it was beyond our reach, just to know would be ground breaking and awesome.
Of course I believe that answer is in the affirmative.

 

I suggest there motives are simple.....to know finally with certainty that we are not alone...no matter how far away.
A more pertinent question may be, what are your motives?

Rather than fabricate some nonsense conspiracy, the reason more than likely, is just to receive some confirmation to positively validate that which most know is a near certainty anyway...ie: the existence of ETI.
In essence the search will continue just as it should.

 

stuff up

 

You're dumber than the SETI folks. That's why your running your mouth about stuff you clearly don't understand in this public science forum. You're insinuating that the SETI folks are confusing Stephen Hawking about this stuff. Get a clue. None of these people are getting rich and you're making a fool of yourself with the dumbshit analysis.

 

Not true, for ETs at least as advanced as humans. If not too far away (quick guess is <100 light years) they can know a great deal about the "intelligent life" of earth (and will when TV et. al. signals reach them).

TV transmission antennae, stack many (about a dozen at least) individual, in phase radiating antennae so that there is little radiation leaving them which is not in the shape of a disk. As the earth spins, the disk being radiated from a station in the tropics, sweeps across the entire heavens twice each day. From this, ET knows the earth revolves 360 degree in 24 hours. From the Doppler shift of the carrier frequency they know Earth's year, the shape of its orbit (nearly circular). Especially now that all TVs of the US must transmit digital signals ET can easily learn how to decode the signals into frames of sequential pictures. (Doing that was quite easy for analogue TV too as between each frame there is a repeated "synchronization signal")

ETs closer to earth may get signal strength adequate to watch more than a minute of the old "I love Lucy" shows, etc. from each TV station that broadcast it.
From it and other consecutive frames they receive, they know "Earthlings" come in two distinct sexes, have two legs, can ride on four legged animals or inside machines they enter and leave via "doors." Their linguists know all the major languages spoken on Earth - meaning of >5000 words in each. They know humans are very aggressive, prone to wars, have thousands of nuclear bombs, and have killed "enemies" with them, etc. Probably ETs project there is little point in trying to communicate with humans, as by the time their replies would reach earth, it is unlikely any advanced society made of such aggressive, self-destructive creatures would still exist.

Billy T adds, many are radiating the legal limit of 500kW with an Effective Radiated Power of megawatts, due to the radiated disk being quite thin. Some with peak ERP >100 mega Watts. (SETI could never afford to radiate that much energy 24/7.) The "disk" is really a very flat cone with about 1.5 (=2x0.75) degrees thick sides whose axis is pointed directly away from center of the earth. As discussed at the link given, the disk is not exactly flat, but a cone to avoid wasting power in "heating hillsides." IE the vertical stack of separate antennae are not exactly in phase.

I also note that there are many other much lower frequency radiators with significant power that operate 24/7. For example WCHS where as a teenager I was paid the same salary as the four engineers with the required first class FCC commercial license got for doing their vacation fill-in shifts. I suspect I was the youngest to ever hold that 1st class license.- Getting it is a tough 4-hour exam, which many fail. WCHS radiated 50kW, 24/7. Paying me saved the station a lot of money each summer as with only three engineers pulling the 8 hour long duty shifts that caused some "triply time" pay hours to occur and quite a few double time pay hours, if I were not doing vacation fill in.

There are also a huge number (>50,000 ?) of radars on ships at sea and scanning the sky for air traffic control with their power concentrated in narrow beams , scanning the full 360 degrees in less than a minute.

SUMMARY: Near by ETs, will know we are here, and much more about us, but may not think it worth while, or even wise, to tell us they exist too.

 

Post 30's SUMMARY is probably the best answer to Fermi's question: "Where is everbody?" I.e. they are there, but don't communicate with aggressive, war minded, self destructive, cultures. - That is against Galactic Law.

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Stars we can see and photograph on clear dark night are much less than 1/millionth of the stars in our galaxy. See next photo stating this another way.
(Volume of galaxy is million times greater than a volume with diameter less than 0.01 of its diameter.)
Again: Where is everybody?

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From Ken Regenweald Post # 17

Neither I nor others have denied the existence of life elsewhere in the universe. What Post caused you to Post the above?

I have given cogent reasons to claim that technological cultures are very rare, with some galaxies having none. From my Post #9

 

From BruceP Post # 29

Instead of calling me dumb, why not try to provide a cogent counter argument to my Post #25 which was prompted by your Post #21: Repeated here so you are not required to find that Post.

 

Probably because he sees it that way as do I. You do seem rather defensive on this issue, why?

You have given reasons sure, and they are countered with many reasons why ETL at all levels should exist.
But also your figures have been questioned in the past.
And again, I must ask you, what is your definition of rare.
Even at the extreme end of the scale intelligent species was only found once in each galaxy. We would still have uncountable numbers to contend with.
As always and obviously, time and distance makes contact rare.....but who knows? In the course of time, as long as we are able to survive as a species, that technologies will not be such as to overcome these barriers.

 

Will SETI’s Unprecedented New Program Finally Find E.T.?

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Stephen Hawking, Frank Drake and dozens of journalists gathered at the Royal Society in London last week to hear astronomers announce a ground-breaking new project to search for intelligent extraterrestrial life called “Breakthrough Listen.” They will be using two of the world’s largest radio telescopes (Green Bank Telescope in West Virginia and the Parkes Radio Telescope in Australia) to listen for radio messages from intelligent alien species. Scientists have chosen to target the nearest million stars as well as the nearest 100 galaxies. This project will also monitor the Galactic plane for months at a time. This unprecedented effort is a collaboration between UC Berkeley and the Breakthrough Prize Foundation, and employs an international team of astronomers and data scientists, including Frank Drake – the father of SETI (Search for ExtraTerrestrial Intelligence).

more at.......


http://www.universetoday.com/121636/will-setis-unprecedented-new-program-finally-find-e-t/

 

Most should note that many reputable people are involved in this search for the answer to mankind's greatest question.
The photo above, besides Stephen Hawking and Frank Drake, also involves Britain's Astronomer Royal, Sir Martin Rees to the right of Frank..

 

From BillyT Post # 30

I am aware that our current technology can send directed signals to Mars & perhaps as far as the Ort Cloud. However, our ordinary TV broadcasts degrade via an inverse square law. I doubt that they could be detected by receivers on Mars. I almost certain that they could mot be detected by receivers at ORT cloud distances. They certainly could not be detected at interstellar distances.

It is also interesting to note that our TV signals have had a short life as broadcasts. Cable TV has become the normal mode of transmission & reception. I wonder how many regular broadcasts still exist. I doubt that there will be any such broadcasts in 20-30 years. The change-over to cable technology results in a very small time-window of opportunity.

BTW:Note that the Arecibo message was intended as a test of the equipment & for PR purposes.

Above quote from https://en.wikipedia.org/wiki/Arecibo_message indicates that the message was not expected to be received by an ET technology.

 

No that is how the signal strength falls off with distance from an Omni-directional source, which TV stations using a dozen or so in phase radiators are not. Their signals are beams, with about 1.5 degree width much like used to communicate with and from the most remote objects man has made - the pioneer space craft, now far beyond the solar wind; but TV beams are radiated in the full 360 circle. This is an advantage as you don't need to know where to aim them. They sweep over most stars twice daily, some with effective radiated power in the mega watts.

possibly true, but the FCC says that JUST in US and its territories (quoted from post 30):
"There were 1,786 full-power {TV} stations operating in the 50 states, the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands as of February 22, 2012." Also as I noted in post 30, there are many (more 50,000 ? 24/7 operating) high power radars projecting well defined (not inverse square) beams for air traffic control and "situation awareness" needed by ships, especially military ships like Aegis destroyers with their powerful electronically steered beams.

I do agree that the time "window" for any technology is short compared to even human life spans. The original searches for ET were all done at about 21 cm wave length, as any civilization would know about this natural radiation from all free space's hydrogen. Perhaps in a few decades some X-ray laser's beam cross section as its beam passes thru the ort cloud will be less than a foot in diameter, but one would need to aim it well to send detectable energy to your choice of the nearest 10,000 stars. "Detectable" mainly boils down to the signal to noise ratio. The cosmic back ground radiation is very weak and needed liquid He (I think) cooled detector to have thermal noise low enough for detection. In the X-ray region there are bands where natural noise would make ET's signals hard to detect, so of course when we have high power X-ray laser with diffraction limited* beam spread, we would not use that part of the X-ray spectrum (nor would ET).

* Best large optical telescopes are diffraction limited, but variation in air density makes earth based looking for ET not able to use fully that limit.

 

It's not likely we will ever actually here an alien message from a technological species. But what's more likely to happen is we will be able to detect life on an exoplanet by the atmosphere it has. For instance an atmosphere with free O2 in it would most likely have some kind of life that keeps replenishing it. Possibly some kind of robot space ships could be sent to several good candidate exoplanets with the ability to produce a human population from our DNA. So in that case who cares if it might take 10,000 years to reach a suitable planet.

 

From Billy T Post #38

I was not aware of such projects. Can you provide a citation providing more details about projects which beam signals over interstellar distances?

I am aware of the Arecibo Signal which was a one-time experiment designed to test the equipment & probably for PR Purposes.