Voyager mission in deep space

On Jul 2, 9:43*am, Sylvia Else wrote:
On 2/07/2012 11:22 PM, Jeff Findley wrote:





In article ,
says...

On 2/07/2012 10:43 PM, Jeff Findley wrote:
In article 529ee44e-f348-4443-a0fa-
, says...

On Jul 2, 7:59 am, Alan Erskine wrote:
On 2/07/2012 9:06 PM, bob haller wrote:

We have been broadcasting our presence by radio and tv for how many
years?

not only would ETs know we exist, but lots about our actions Wars
etc.........

i wonder how far the futherest radion waves have traveled by now?

putting it another way, if we were the ETS would we want to go meet
people liker ourselves?

As has been said many times before, the signals we have been sending out
are very low power and therefore very short range. *It wouldn't even
reach the nearest star outside our solar system.

thats assuming the ETs receivers are no better than our own........

It's all of the background noise that would be a problem. *Even if they
could amplify the signal, they'd also amplify the background noise.

Physics. *Learn some.

With a suitable (this is big directional) antenna, they can achieve a
sufficient signal to noise ratio.

There are limits to this. *The orbit of the earth limits how far away
from the sun our transmissions can be. *Add to that fact that the sun
outputs electromagnetic radiation, and you've got the beginnings of the
problem the ET's would need to solve. *They're antenna would need to be
*very* directional indeed to mask the output of our sun while searching
for transmissions from any planets in our solar system.

However, the more directional the antenna, the more difficult it is to
pick anything up by chance.

I'm not a radio telescope expert, but there must be a hard limit,
imposed by physics, to how far away the ET's could be and still be able
to pick out our faint signal while masking our sun's emissions. *By
astronomical standards, that limit certainly won't be very far.

I don't think there's a limit in that sense. Quantum mechanics says that
there's a certain minimum size of antenna that will work for a given
frequency at a given distance (because otherwise you'd violate the
uncertainty principle regarding the lateral position and momentum of the
individual arriving photons). It seems to me that if you double the
distance you have to double the linear dimension of the antenna.

Eventually, of course, it becomes unmanagably large.

Sylvia.

thats assuming the ETs are stuck at one position. they may well be
spread thruout the galaxy, or use something akin to wormholes to
communicate.

they are likely there and we just havent stumbled onto them yet

Aliens know that there is life on earth since millions of years.

Any scope pointing to earth from some star far away will discover the
atmospheric composition.

The atmosphere of the earth shouldn't contain all that oxygen.
It is "artificially" produced then. There is life on earth.

That signal has been sent since 2-3 BILLION years...

For any aliens out there the earth is a very interesting place. We will
achieve that stage soon (in a few years or a decade, depending on
astronomy budgets) Already we have been able to detect the composition
of planets passing in front of their star. In a few decades we will
be able to detect planets like earth easily.

Aliens, of course, should be more advanced than we are if they just
started (say) 1 million years ahead of us.

So, they know that life has started here. If thet did visit us in those
untold eons of time before mankind appeared they left no visible traces
on earth. Arthur Clarke proposed that they would have left traces in
space so as to wait till a space faring civilization appears.

"Alan Erskine" wrote in message
ond.com...

On 2/07/2012 9:06 PM, bob haller wrote:


We have been broadcasting our presence by radio and tv for how many
years?

not only would ETs know we exist, but lots about our actions Wars
etc.........

i wonder how far the futherest radion waves have traveled by now?

putting it another way, if we were the ETS would we want to go meet
people liker ourselves?



As has been said many times before, the signals we have been sending out
are very low power and therefore very short range. It wouldn't even reach
the nearest star outside our solar system.


That's not entirely true.

For example, http://en.wikipedia.org/wiki/Arecibo_Message was quite
high-powered. Now, it won't reach anything significant, but anything within
38 light years along that line could probably detect it.

We also have http://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

Some of the high-powered military radars that were pointed over the horizon
are probably detectable by an advanced civilization.

That said, SETI does have some severe limits. For example with intentional
messages such as the two above, if you blink, you miss them.

And otherwise, we're starting to go relatively radio silent as a) we're
using radio more efficiently (and more ground-based communications in many
cases) and in general, the signals we're transmitting are often compressed,
which means that they look more and more like plain noise.






--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

With a suitable (this is big directional) antenna, they can
achieve a sufficient signal to noise ratio.

There are limits to this. The orbit of the earth limits how far
away from the sun our transmissions can be. Add to that fact that
the sun outputs electromagnetic radiation, and you've got the
beginnings of the problem the ET's would need to solve. They're
antenna would need to be *very* directional indeed to mask the
output of our sun while searching for transmissions from any planets
in our solar system.

A peanut-gallery question - How many orders of magnitude more
difficult would it be to do in the EM bands what we're doing with
(visible?) light and transits of stars in our search for exo-solar
planets?

rick jones
--
denial, anger, bargaining, depression, acceptance, rebirth...
where do you want to be today?
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

On Mon, 2 Jul 2012 11:32:53 -0400, "Greg \(Strider\) Moore"
wrote:

That's not entirely true.

For example, http://en.wikipedia.org/wiki/Arecibo_Message was quite
high-powered. Now, it won't reach anything significant, but anything within
38 light years along that line could probably detect it.

We also have http://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

And you must include radar events like observations of Mercury, Venus,
and asteroids by Arecibo. The radar signal was huge, the distance
great, and the target small. The signal would have continued out into
deep space in whatever direction it was pointing, save for the small
fraction of it that hit the target and bounced back. Our transmissions
to the Voyagers and Pioneers by the DSN have also been extremely
powerful. They would have been detectable, at least as a unnatural
source.

Brian

On 3/07/2012 4:48 AM, Rick Jones wrote:
With a suitable (this is big directional) antenna, they can
achieve a sufficient signal to noise ratio.

There are limits to this. The orbit of the earth limits how far
away from the sun our transmissions can be. Add to that fact that
the sun outputs electromagnetic radiation, and you've got the
beginnings of the problem the ET's would need to solve. They're
antenna would need to be *very* directional indeed to mask the
output of our sun while searching for transmissions from any planets
in our solar system.

A peanut-gallery question - How many orders of magnitude more
difficult would it be to do in the EM bands what we're doing with
(visible?) light and transits of stars in our search for exo-solar
planets?

rick jones


To pick out UHF signsals, the antennas would have to be about 6 orders
of magnitude bigger in linear dimension.

But they don't have to be solid, so it's no so easy to determine the
relative difficulty.

Sylvia.

On 3/07/2012 1:32 AM, Greg (Strider) Moore wrote:
"Alan Erskine" wrote in message
ond.com...

On 2/07/2012 9:06 PM, bob haller wrote:


We have been broadcasting our presence by radio and tv for how many
years?

not only would ETs know we exist, but lots about our actions Wars
etc.........

i wonder how far the futherest radion waves have traveled by now?

putting it another way, if we were the ETS would we want to go meet
people liker ourselves?



As has been said many times before, the signals we have been sending
out are very low power and therefore very short range. It wouldn't
even reach the nearest star outside our solar system.


That's not entirely true.

For example, http://en.wikipedia.org/wiki/Arecibo_Message was quite
high-powered. Now, it won't reach anything significant, but anything
within 38 light years along that line could probably detect it.

We also have http://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

There not the ones Bob was talking about nor are they the ones I
mentioned. I agree with your point about military radar, but it would
probably also look like noise.

On 3/07/2012 9:10 AM, Brian Thorn wrote:
On Mon, 2 Jul 2012 11:32:53 -0400, "Greg \(Strider\) Moore"
wrote:

That's not entirely true.

For example, http://en.wikipedia.org/wiki/Arecibo_Message was quite
high-powered. Now, it won't reach anything significant, but anything within
38 light years along that line could probably detect it.

We also have http://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

And you must include radar events like observations of Mercury, Venus,
and asteroids by Arecibo. The radar signal was huge, the distance
great, and the target small. The signal would have continued out into
deep space in whatever direction it was pointing, save for the small
fraction of it that hit the target and bounced back. Our transmissions
to the Voyagers and Pioneers by the DSN have also been extremely
powerful. They would have been detectable, at least as a unnatural
source.

Brian

To make such an assumption, one must first also determine the size of
the receiving antenna/antennae.

On Jul 2, 10:06*pm, Alan Erskine wrote:
On 3/07/2012 9:10 AM, Brian Thorn wrote:



On Mon, 2 Jul 2012 11:32:53 -0400, "Greg \(Strider\) Moore"
wrote:

That's not entirely true.

For example,http://en.wikipedia.org/wiki/Arecibo_Messagewas quite
high-powered. Now, it won't reach anything significant, but anything within
38 light years along that line could probably detect it.

We also havehttp://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

And you must include radar events like observations of Mercury, Venus,
and asteroids by Arecibo. The radar signal was huge, the distance
great, and the target small. The signal would have continued out into
deep space in whatever direction it was pointing, save for the small
fraction of it that hit the target and bounced back. Our transmissions
to the Voyagers and Pioneers by the DSN have also been extremely
powerful. They would have been detectable, at least as a unnatural
source.

Brian

To make such an assumption, one must first also determine the size of
the receiving antenna/antennae.

i have read about having small multipl antennas / receivers a distance
apart, which effectively make them very large. their signals are
somehow combined together electronically..

so a ET light years away may be able to detect us........

doesnt a nuke explosion put off a EMP pulse? that might be like a
strobe light for other civilations.
hey check out this area???

so then multiple smaller antennas could get pointed our way......

On 3/07/2012 10:25 PM, Fred J. McCall wrote:
bob haller wrote:

On Jul 2, 10:06 pm, Alan Erskine wrote:
On 3/07/2012 9:10 AM, Brian Thorn wrote:

On Mon, 2 Jul 2012 11:32:53 -0400, "Greg \(Strider\) Moore"
wrote:

That's not entirely true.

For example,http://en.wikipedia.org/wiki/Arecibo_Messagewas quite
high-powered. Now, it won't reach anything significant, but anything within
38 light years along that line could probably detect it.

We also havehttp://en.wikipedia.org/wiki/A_Message_From_Earth.

Those are just the intentional ones.

And you must include radar events like observations of Mercury, Venus,
and asteroids by Arecibo. The radar signal was huge, the distance
great, and the target small. The signal would have continued out into
deep space in whatever direction it was pointing, save for the small
fraction of it that hit the target and bounced back. Our transmissions
to the Voyagers and Pioneers by the DSN have also been extremely
powerful. They would have been detectable, at least as a unnatural
source.

To make such an assumption, one must first also determine the size of
the receiving antenna/antennae.


i have read about having small multipl antennas / receivers a distance
apart, which effectively make them very large. their signals are
somehow combined together electronically..


VLBI isn't magic.


so a ET light years away may be able to detect us........


VLBI won't help with that.


doesnt a nuke explosion put off a EMP pulse?


Only under specific conditions.


that might be like a strobe light for other civilations.
hey check out this area???

so then multiple smaller antennas could get pointed our way......


Or perhaps they'll read our existence in their stool patterns in the
morning? It's as likely as the things you think "might" be....



Do you have a particular reason for being obnoxious?

Sylvia.