Faint signals

The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.
It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). After a century or so, it becomes radio silent above
the kW range.

A deliberate directional transmission changes the game. It should be
the eighth factor in the drake equasion.....the desire to say 'hello'.

Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.
It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). After a century or so, it becomes radio silent above
the kW range.


Two problems with this hypothesis.

1.) Unlike Huygens, Earth's total RF signal output is immense and
omnidirectional, so that it's been stated that if someone on another
star system set up a SETI-like program for ET RF signal detection within
a hundred LY's, Earth would stand out like a sore thumb as soon as they
aimed their radio telescopes anywhere near it in the sky.
2.) It might well be possible that RF transmission of messages becomes
quickly obsolete in historical terms as the ET civilization's
technology advances. RF is limited by the speed of light, and maybe some
other form of communications quickly replaces it within a few centuries
equivalent time after it begins in all ET civilizations.
Remember the serious proposal to contact Mars with giant mirrors like a
heliograph a century or so back.

Using the new multi-dimensional theories involved in Dark Matter and
Dark Energy theory it might well be possible to do point-to-point
communications anywhere in the universe pretty much instantaneously via
other dimensions and modification of the space-time matrix.
That would make RF-based communication use about as obsolete as using
smoke signals for any civilization that perfected such a technology.

Pat

On Oct 25, 7:20*pm, Pat Flannery wrote:
Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. *The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. *A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. *It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.
It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). *After a century or so, it becomes radio silent above
the kW range.

Two problems with this hypothesis.

1.) Unlike Huygens, Earth's total RF signal output is immense and
omnidirectional, so that it's been stated that if someone on another
star system set up a SETI-like program for ET RF signal detection within
a hundred LY's, Earth would stand out like a sore thumb as soon as they
aimed their radio telescopes anywhere near it in the sky.

I used the goldstone-huygens story because it represents a sensitivity
of about 10E-27 W/m2, higher than any claimed for a seti survey.

Alpha Centauri is about 25000 times farther than saturn, so the
corresponding signal would have to be 625000000 times stronger.
Multiple radio sources are not additive, so the total omnidirectional
signal power from a planet would have to be considerably greater than
625 MW. However radio transmitters concentrate their energy in a
disk, toward the horizon, so we (or 'they') might get lucky...
intermittently.

Of course the bigger the dish, the better the chances.



*2.) It might well be possible that RF transmission of messages becomes
quickly obsolete in historical terms as the ET civilization's *
technology advances. RF is limited by the speed of light, and maybe some
other form of communications quickly replaces it within a few centuries
equivalent time after it begins in all ET civilizations.
Remember the serious proposal to contact Mars with giant mirrors like a
heliograph a century or so back.

Using the new multi-dimensional theories involved in Dark Matter and
Dark Energy theory it might well be possible to do point-to-point
communications anywhere in the universe pretty much instantaneously via
other dimensions and modification of the space-time matrix.
That would *make RF-based communication use about as obsolete as using
smoke signals for any civilization that perfected such a technology.

Pat

I have read about multi dimensional theories but not any that
incorporated dark matter and energy, can you lend me a link?

Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.


A square of just 1 000 miles floating in space would do it. Not very
far away from our own technology.

It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). After a century or so, it becomes radio silent above
the kW range.


Note this:

Any civilization examining the spectrum of the earth will notice that
the atmosphere contains too much oxygen. A tell-tale sign of life.

This signal has been there for around a billion years already... This
means everybody in a radius of several thousand light years knows that
life is here in this planet since a LONG time.

It would be considered then as a good target for directed emissions.


A deliberate directional transmission changes the game. It should be
the eighth factor in the drake equasion.....the desire to say 'hello'.


--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32

On Oct 26, 3:15*am, jacob navia wrote:
Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. *The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. *A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. *It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.

A square of just 1 000 miles floating in space would do it. Not very
far away from our own technology.

At a mass of one ton per square mile it would be just a million tons.
Still, in less than a century we might be building solar power
satellites, it would not then be such a big step.

It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). *After a century or so, it becomes radio silent above
the kW range.

Note this:

Any civilization examining the spectrum of the earth will notice that
the atmosphere contains too much oxygen. A tell-tale sign of life.

This signal has been there for around a billion years already... This
means everybody in a radius of several thousand light years knows that
life is here in this planet since a LONG time.

It would be considered then as a good target for directed emissions.

The spitzer telescope detected a jupiter sized planet 150 lys away,
however it had a temperature of a thousand degrees being in a 3.5 day
orbit. A space telescope a few hundred feet in diameter could
probably take the spectrum of earth from ten lys distance.

The time between detecting an oxygen planet and the ability to pick up
radio signals from it might only be decades. After the ability to
tune in live there might be less of a desire to communicate.

What ET would want to spoil the best show in this qudrant of the
galaxy.



A deliberate directional transmission changes the game. *It should be
the eighth factor in the drake equasion.....the desire to say 'hello'.

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatiquehttp://www.cs.virginia.edu/~lcc-win32

On 25 Oct, 20:16, Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. *The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. *A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.

That is not inherently impossible. You can build lasrge phased arrays
in space.

There are about 10000 stars within 100lys. *It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.
It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). *After a century or so, it becomes radio silent above
the kW range.

A deliberate directional transmission changes the game. *It should be
the eighth factor in the drake equasion.....the desire to say 'hello'.

What about phase array technology. We can envisage it. ET will have
it.


- Ian Parker

Ian Parker wrote:
:
:What about phase array technology. We can envisage it. ET will have
:it.
:

Thus we must be ET, since we've had phased array technology for half a
century or so now.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson

On 28 Oct, 02:32, Fred J. McCall wrote:
Ian Parker wrote:

:
:What about phase array technology. We can envisage it. ET will have
:it.
:

Thus we must be ET, since we've had phased array technology for half a
century or so now.

Not on the scale envisaged.


- Ian Parker

On Oct 25, 1:16*pm, Totorkon wrote:
The titan lander, Huygens, had a radio output about equal to a cell
phone, in the one watt range. *The 34m Goldstone radio dish was able
to pick up some signal from a billion miles away. *A megawatt signal,
like that of the WW2 German goliath, from a distance of four lys,
would require a dish 30 miles in diameter.
There are about 10000 stars within 100lys. *It would require almost a
million square miles of collection area to pick up the same faint
signal from the edge of that distance.
It has been suggested that as a civilization advances, its
communication becomes based on fiber optic and directional radio (like
satellite TV). *After a century or so, it becomes radio silent above
the kW range.

A deliberate directional transmission changes the game. *It should be
the eighth factor in the drake equasion.....the desire to say 'hello'.

I miscalculated. To pick up the faintest signal of a several hundred
watt radio transmitter from four lys distant would require a dish of
about a mile in diameter. 100 lys would require about 700 sq miles.
That million mile behemoth could reach out to 5000 lys, encompassing
50 million stars.

Like goldstone-huygens at that limit, it would be unintelligible.
But we would know we are not alone.