Humanity cannot hide from radio transmitting civilizations

[kerbiloid]

What we mean

Spoiler

 

 

What they get

Spoiler

(Because they see the digits written from right to left, so they presume that the picture should be horizontal, to keep the digits growing from top to bottom).

"1,2 Freddy's coming for you
3,4, better lock your door
5,6, grab your crucifix
7,8, gonna stay up late
9,10, never sleep again

(How long has it been since)
you've (the head) been on Elm Street (two parallel vertical rows of tree-like things and either two cars one-by-one, or the road marks in between)?

(Some huge maybe worm, maybe fish, maybe other huge horizontal creature with opened jaws to the very right, swallowing a human-like creature)

 

 

Are we sure, it's a contact we want?

[Riven]

3 hours ago, magnemoe said:

Lasers probably makes more sense for interplanetary communication. However their cone is even narrower so they mostly work if you know target location well. 

There are a lot of challenges to the laser comm approach such as the narrow cone as you point out. There's also atmospheric scattering and interference form the Sun, but those will eventually be overcome in the coming years through robust error correction.

4 hours ago, magnemoe said:

You also don't want to send an signal stronger than you want to. Not only does it use more power and require an more expensive transmitting system but you also take up more bandwidth. 
Radio noise from earth is probably going down as we move away from huge transmitting towers over to cell networks. 
Yes it cases you want lots of power like an search radar but this is not used all the time.

Right, while you want to send a signal only as strong as you need, other factors have to be considered. Though power output isn't necessarily correlated to bandwidth - you can design high power resonators (e.g. TWTAs for space applications) that have a narrow bandwidth. The DSN transceiver package can transmit whatever bandwidth they want at tens of kilowatts, at a high price, of course. This provides a great visualization of the DSN's capabilities in real time. When you look at the data from it, you start to wonder if any alien out there can pick out our RF signals if they try - it's an argument against the OP's topic: the power we receive from spacecraft like Voyagers 1 and 2 is just so minuscule:

That's about 700k times weaker than what your typical WiFi radio is capable of receiving. (Every 3db you double your power.) But, as you said,

4 hours ago, magnemoe said:

Probably easier to look for bio signatures as they don't require high tech civilizations using specific technology. 

we can forget RF and do that with transits, direct imaging (oh please pls JWST... pls launch successfully), and spectrometers to find those biosignatures.

[DDE]

21 hours ago, magnemoe said:

Probably easier to look for bio signatures as they don't require high tech civilizations using specific technology. 

Except it’s likely that bio signatures are more varied than technological solutions.

[kerbiloid]

Like right now they explore the biosignatures on Mars, and we are still not sure if they are biogenic.

P.S.
We should search periodic patterns in the exoplanet radio emitting activity, matching the planet rotation period.
Especially also matching their largest moon orbital period, or integer numbers of the planet rotation periods close to an integer part of the moon period (a "week").

Say, an alien observer could easily notice clear 7-day periods in ours.

This way we can list their TV schedule and explore their habits and cyclic daily and weekly activity.

Edited August 3, 2019 by kerbiloid

[magnemoe]

1 hour ago, DDE said:

Except it’s likely that bio signatures are more varied than technological solutions.

We are not looking for Mars or Europa level of life here, none of them can have intelligent life, even advanced life is extremely unlikely. 

An oxygen atmosphere is much easier to spot, yes you can get oxygen other ways as in UV breaking down water vapor in the upper atmosphere but that is also an edge case and you have other markers on to you can use once you get oxygen.  

And yes this way you could spot earth very far away.

33 minutes ago, kerbiloid said:

Like right now they explore the biosignatures on Mars, and we are still not sure if they are biogenic.

P.S.
We should search periodic patterns in the exoplanet radio emitting activity, matching the planet rotation period.
Especially also matching their largest moon orbital period, or integer numbers of the planet rotation periods close to an integer part of the moon period (a "week").

Say, an alien observer could easily notice clear 7-day periods in ours.

This way we can list their TV schedule and explore their habits.

How long will we have broadcast TV over the air, can not imagine it lasting much longer than 20-30 years. 
So it lasted 100 year. You have to get pretty close to pick then up trough and even so you need an monster antenna.

[kerbiloid]

1 hour ago, magnemoe said:

How long will we have broadcast TV over the air, can not imagine it lasting much longer than 20-30 years. 

Since 1930s, iirc.

1 hour ago, magnemoe said:

You have to get pretty close to pick then up trough and even so you need an monster antenna.

We don't need to watch, but any weekly schedule of signal power distribution itself should be artificial.

Energy consumption and emission schedule as well. When they return home and start watching TV and cooking, when they have weekends.

Edited August 3, 2019 by kerbiloid

[Guest]

On 8/4/2019 at 12:38 AM, magnemoe said:

And yes this way you could spot earth very far away.

I wouldn’t think the atmospheric composition would have much of a difference in the detection range of a planet. It’s a noticeable biomarker sure but with our current methods you are relying on the planet to either be within a plane relative to us so that you can see its  transit or you are relying on the planet to have a fast enough orbital period so that you can tell it’s there by the wobble induced in its parent star. The presence of oxygen in either case has no affect on detection. It also doesn’t help detect anaerobic life so a lack of oxygen couldn’t be used to rule out anything much beyond there isn’t an earthlike ecosystem present.

Edited August 5, 2019 by Guest

[magnemoe]

24 minutes ago, Dale Christopher said:

I wouldn’t think the atmospheric composition would have much of a difference in the detection range of a planet. It’s a noticeable biomarker sure but with our current methods you are relying on the planet to either be within a plane relative to us so that you can see its  transit or you are relying on the planet to have a fast enough orbital period so that you can tell it’s there by the wobble induced in its parent star. The presence of oxygen in either case has no affect on detection. It also doesn’t help detect anaerobic life so a lack of oxygen couldn’t be used to rule out anything much beyond there isn’t an earthlike ecosystem present.

You are correct, its much harder to analyze the atmosphere than spotting the planet in the first place. 

However detecting radio noise from earth is not trivial, Earth telescopes would not detect radio noise from earth if located at Proxima Centauri. Yes using telescopes the size of an small moon you could detect earth radio noise out to 50 LY. 
But at this scale you would also be be able to directly image exoplanets and analyze their atmosphere. The light reflected of earth is so much stronger than out radio signals. 

[YNM]

On 7/21/2019 at 10:07 PM, farmerben said:

If aliens send us a radio message, we have no choice but to reply.

We already sent things off before them sending us anything.

 

[kerbiloid]

Spoiler

52 minutes ago, magnemoe said:

However detecting radio noise from earth is not trivial, Earth telescopes would not detect radio noise from earth if located at Proxima Centauri.

Thank goodness...
So, they can't listen our amateur stations, FM-music, and police radio.
Otherwise they would treat us as defective.

 

[Exploro]

On 7/21/2019 at 3:07 PM, farmerben said:

If aliens send us a radio message, we have no choice but to reply.

All the other humans on Earth will eventually find out about the alien signal.  With a moderate amount of wealth any human could send a directional radio signal back toward the alien star without the other humans even knowing about it.  

No matter what government policies are adopted.  There is almost zero probability that transmission capability will not fall into the hands of 14 year old boys, and cult leaders, etc.  

Therefore to try to hide is to accept the reality that other humans will act against your interests.  

Therefore our safest bet is show them what credible humans are like, because we must warn them against pranks, hoaxes, and viruses we cannot prevent other humans from sending.  

We require transmitters with antennae 60 meters in diameter or greater with an output of 10 to 20 kW to communicate with the Voyagers, spacecraft still within our proverbial backyard. Deliberately sending signals deeper into space require radio equipment is comparable or better than what the DSN uses. Thus, given the cost necessary to build a DSN-grade transmitter, we can easily eliminate random 14 year olds and cults, these groups would lack the capability to even attempt to construct transmitters such as those. One would have to be wealthy or have the backing of a governmental or scientific entity to possess funds necessary to build such facilities.

Further such facilities are not easy to hide...I mean a giant parabolic antenna suddenly appearing in some random locale would draw attention. Even if built in a remote locale, orbiting imaging satellites (both civil and military) would reveal the clandestine activity. And what is more these components would need to be purchased, fabricated, shipped out, and assembled. Power would need to be brought out to the transmitter. All of these logistical consideration would make a surreptitious assembly and operation of clandestine transmitter unlikely.
 

 

[Nightside]

On 7/21/2019 at 8:07 AM, farmerben said:

 

If aliens send us a radio message, we have no choice but to reply*

 

*REPLY ALL 

Maybe other species in the galaxy just automatically filter unsolicited broadcast radio signals that they receive into their spam folder. 

[magnemoe]

On 8/5/2019 at 6:21 PM, Exploro said:

We require transmitters with antennae 60 meters in diameter or greater with an output of 10 to 20 kW to communicate with the Voyagers, spacecraft still within our proverbial backyard. Deliberately sending signals deeper into space require radio equipment is comparable or better than what the DSN uses. Thus, given the cost necessary to build a DSN-grade transmitter, we can easily eliminate random 14 year olds and cults, these groups would lack the capability to even attempt to construct transmitters such as those. One would have to be wealthy or have the backing of a governmental or scientific entity to possess funds necessary to build such facilities.

Further such facilities are not easy to hide...I mean a giant parabolic antenna suddenly appearing in some random locale would draw attention. Even if built in a remote locale, orbiting imaging satellites (both civil and military) would reveal the clandestine activity. And what is more these components would need to be purchased, fabricated, shipped out, and assembled. Power would need to be brought out to the transmitter. All of these logistical consideration would make a surreptitious assembly and operation of clandestine transmitter unlikely.
 

 

Good point, in short it will require someone rich, an decent sized organisation or an nation state. 
The first two can hardly do it in secret. 

However if the aliens know its life on earth and signal was directed specific towards earth they might keep it under observation some time after signal arrive the signal returned could be far less demanding. 
Could is the key word, the aliens would have little reason to look for an very weak signal if they expect an return, say signal require an 20 meter telescope to receive. They would then expect reply to be sent from an 20 meter telescope and an return to them at around the same signal strength.
Not somebody pointing an radar at them and send morse. 

 

[kerbiloid]

When they blasted ~1 Mt in ionosphere, the radio storm blocked communications for an hour or more in hundreds kilometers around.

Let's blast something in Jupiter ionosphere and watch what happens.

And what if start hitting it with a microwave beam? Maybe it will amplify our transmissions.

And vice versa, maybe it amplifies radiosignals from the far away?

[Guest]

On 8/3/2019 at 6:32 AM, Riven said:

oh please pls JWST... pls launch successfully)

Yessssssssss please! For the lub of jebus! Having this blow up on the pad would be an absolute tragedy 

Edited August 9, 2019 by Guest

[Cheif Operations Director]

Could’nt we just scramble the radio signals by sending out junk on as many frequencies as possible? Then just let it up when we need too

Edited August 13, 2019 by Cheif Operations Director

[kerbiloid]

6 hours ago, Cheif Operations Director said:

Could’nt we just scramble the radio signals by sending out junk on as many frequencies as possible?

They will add our transmissions to spam, ban us, then call a galactic sysadmin.

[Cheif Operations Director]

1 minute ago, kerbiloid said:

They will add our transmissions to spam, ban us, then call a galactic sysadmin.

We will be fine... I guess

My solution: SPAM THE AIRWAVES!

[farmerben]

On 8/5/2019 at 11:21 AM, Exploro said:

We require transmitters with antennae 60 meters in diameter or greater with an output of 10 to 20 kW to communicate with the Voyagers, spacecraft still within our proverbial backyard. Deliberately sending signals deeper into space require radio equipment is comparable or better than what the DSN uses. Thus, given the cost necessary to build a DSN-grade transmitter, we can easily eliminate random 14 year olds and cults, these groups would lack the capability to even attempt to construct transmitters such as those. One would have to be wealthy or have the backing of a governmental or scientific entity to possess funds necessary to build such facilities.

Further such facilities are not easy to hide...I mean a giant parabolic antenna suddenly appearing in some random locale would draw attention. Even if built in a remote locale, orbiting imaging satellites (both civil and military) would reveal the clandestine activity. And what is more these components would need to be purchased, fabricated, shipped out, and assembled. Power would need to be brought out to the transmitter. All of these logistical consideration would make a surreptitious assembly and operation of clandestine transmitter unlikely.
 

 

The voyager probe is using a 3.7m dish and less than 500 W of power.  Exceeding the strength of that signal is trivial for a 14 year old boy.  

Coast to Coast AM with George Norry is broadcast simultaneously from multiple 50 kW transmitters.    I have switched back and forth between Amarillo, Minneapolis and Denver with the receiver in a car on a cloudy night.   So the aliens have already heard about the lizard people who live inside our hollow planet.      And they are busy right now figuring out if broadcast high school football games are actually encrypted messages. 

 A decent rectenna is easy to conceal, since the individual wires cannot be resolved by satellite imaging and they can be laid out on the ground, or disguised as power lines.

Nearly every small city already has the stuff on hand to send a directed transmission vastly stronger than all the other radio noise combined.  

[Cheif Operations Director]

5 hours ago, farmerben said:

The voyager probe is using a 3.7m dish and less than 500 W of power.  Exceeding the strength of that signal is trivial for a 14 year old boy.  

Coast to Coast AM with George Norry is broadcast simultaneously from multiple 50 kW transmitters.    I have switched back and forth between Amarillo, Minneapolis and Denver with the receiver in a car on a cloudy night.   So the aliens have already heard about the lizard people who live inside our hollow planet.      And they are busy right now figuring out if broadcast high school football games are actually encrypted messages. 

 A decent rectenna is easy to conceal, since the individual wires cannot be resolved by satellite imaging and they can be laid out on the ground, or disguised as power lines.

Nearly every small city already has the stuff on hand to send a directed transmission vastly stronger than all the other radio noise combined.  

Well they would have to be within 90 light years for that

Since the 20s-30s is when radio took off. Really in all honestly within 60 light years of us (1950s) to be hearing radio broadcast for high school football games, Although that is kind of neat to think that somewhere in the universe their might be a signal from a random high school football game somewhere in America that every one has forgotten about, 

Hmm, an alien source could pick up all of the World War Two radio transmissions in theory atleast

Edited August 14, 2019 by Cheif Operations Director

[magnemoe]

3 hours ago, Cheif Operations Director said:

Well they would have to be within 90 light years for that

Since the 20s-30s is when radio took off. Really in all honestly within 60 light years of us (1950s) to be hearing radio broadcast for high school football games, Although that is kind of neat to think that somewhere in the universe their might be a signal from a random high school football game somewhere in America that every one has forgotten about, 

Hmm, an alien source could pick up all of the World War Two radio transmissions in theory atleast

The problem is that unidirectional signals fades fast.  
As I understand an 1 megawatt broadcast signal would not be detectable at 50 lightyear even with an planet sized telescope as the signal to noise level  would be to high. 
Add that early radio used frequencies who bounced off the atmosphere to increase range, TV does not. Now you might be able to pick up WW2 search radars or at least the cold war ones who was both in megawatt range and directional but they are just pings. 

[Cheif Operations Director]

1 hour ago, magnemoe said:

The problem is that unidirectional signals fades fast.  
As I understand an 1 megawatt broadcast signal would not be detectable at 50 lightyear even with an planet sized telescope as the signal to noise level  would be to high. 
Add that early radio used frequencies who bounced off the atmosphere to increase range, TV does not. Now you might be able to pick up WW2 search radars or at least the cold war ones who was both in megawatt range and directional but they are just pings. 

That did occur to me at least in principle, but it is still cool think that you could theoretically hear a high school  football game from 1950s that pretty much every would have forgotten now, I mean the players would be about 80-90 years old. In. a few hundred years with a large enough dish you could still hear it. That is just cool. We could watch TV shows etc, 

[Starstruck69]

If they have sufficient technology to decipher the message then the human race has a very serious problem..

Think about the crap that has gone out over the airwaves in the past century. For example,

Eurovision song contest:(

we are all doomed.

[kerbiloid]

Eurovision will be later. A lightspeed delay.
Currently they are watching and listening political transmissions of late 1930s and guessing what will happen with the League of Nations.

Also that means that their astronomers can absorb some human ideas of that historical period, watch their practical implementation in real time, analyze mistakes, and try that in their homeworld.
Better they would watch Eurovision...

Edited August 16, 2019 by kerbiloid

[farmerben]

On 8/14/2019 at 10:08 PM, magnemoe said:

The problem is that unidirectional signals fades fast.  
As I understand an 1 megawatt broadcast signal would not be detectable at 50 lightyear even with an planet sized telescope as the signal to noise level  would be to high. 
Add that early radio used frequencies who bounced off the atmosphere to increase range, TV does not. Now you might be able to pick up WW2 search radars or at least the cold war ones who was both in megawatt range and directional but they are just pings. 

A planet sized telescope is not so unreasonable.  I hope we build one soon.   

At some range all our signals are undetectable for a given receiver.  My argument starts with the assumption that some signals are detected.  If some of our signals are detectable, then there is really nothing we can do to prevent other humans from transmitting messages that will drown out all other man made radio noise.

 

 

Also, people have already tried it.

https://en.wikipedia.org/wiki/List_of_interstellar_radio_messages

 

I love the part where Seth Shostak and Frank Drake refused to sign a resolution saying "worldwide scientific, political and humanitarian discussion must occur before any message is sent"