• We have updated the guidelines regarding posting political content: please see the stickied thread on Website Issues.

ET cant hear us!

call me conservative, but do we really want to broadcast our presence to potentially hostile alien races?
 
fluffle said:
call me conservative, but do we really want to broadcast our presence to potentially hostile alien races?
Click to expand...

Too late to worry, we've been doing it since at least the mid 30s (see Carl Sagan's 'Contact') so if there's anyone interested within about 50-65 light years, they know we're here.

Of course they might think that 'Star Trek' and 'Doctor Who' are documentaries (as in Galaxy Quest) and be avoiding us like the plague or fleeing the galaxy before the Daleks catch them.
 
Timble said:
(see Carl Sagan's 'Contact')
Click to expand...

only like a million times. :)

Of course they might think that 'Star Trek' and 'Doctor Who' are documentaries (as in Galaxy Quest) and be avoiding us like the plague or fleeing the galaxy before the Daleks catch them.
Click to expand...


let's just hope they see el dorado, or a couple of minutes of MTV.
 
Just a thought but I (and others) have been a bit suspicious of Ananova for a while and I wonder if this report is really delivering the story straight or complete enough to get a rounded point of view? There is no mention of this on the SETI site but they do link to a Washington Post article on this meeting:

http://www.washingtonpost.com/wp-dyn/articles/A48950-2004Aug7.html

in which Drake says (on page 2):

Ideally we would simply eavesdrop on the cosmos and pick up leakage from alien TV stations. But leakage is faint and extremely hard to detect. Drake and Murray argue that we should look for beacons, the intentional messages from the ETs. But this raises some squishy notions of alien behavior. Why would any intelligent civilization want to shout into the night sky?

"Intelligent creatures do weird things," Drake answered. "They would construct a beacon because it is emotionally or philosophically important."
Click to expand...

This would suggest that all "leakage" is difficult anyway so we should be looking for other sources of signal anyway - I'd imagine the "leakage" idea would depend on a number of assumptions about intelligent life and their communications.

The New Scientist article on this is longer and goes into more detail on this and makes more sense (and is far more positive):

Chances of aliens finding Earth disappearing

15:59 09 August 04

A pioneer of the search for extraterrestrial intelligence (SETI) has warned that for any intelligent aliens trying to search for us, "the Earth is going to disappear" very soon.

Frank Drake's point, made at a SETI workshop at Harvard University on Friday, is that television services are increasingly being delivered by technologies that do not leak radio frequencies into space.

But he added that in some ways the observation is good news for SETI, as it means that the failure of Earth-based observers to detect aliens so far may be less worrisome than it would otherwise seem.

Most SETI efforts have focused on detecting radio signals that might be emitted by intelligent beings on planets around nearby stars. For humans, such signals "are the strongest signs of our existence", Drake said, thanks to television.

Traditional television broadcast antennas put out one megawatt each, and this radio-wave bubble now extends about 50 light years out from the solar system.


Straight down


But that is changing fast, Drake says. More and more television is now delivered by cable, with no radio-frequency leakage to space, and by direct-broadcast satellites that put out just 20 watts per channel, all efficiently directed straight down the intended areas on the Earth's surface.

So from the point of view of being detected through such inadvertent broadcasts, the longevity of humanity's detectability may be just 100 years.

And longevity may be the most important figure in Drake's famous equation for estimating the number of detectable intelligent civilisations on other worlds. The best estimates show that all the other crucial factors nearly cancel out, so that the number of such civilisations in our Milky Way galaxy is roughly equal to their average longevity of detectability in years.


Laser beacon


Drake's insight has important implications for search strategies. It means that eavesdropping on unintended alien transmissions is unlikely to succeed and "argues for an emphasis on detecting beacons", i.e. signals intentionally sent our way.

Some SETI strategies have already begun shifting toward that approach, including efforts to find optical beacons based on high-powered lasers deliberately aimed at nearby stars.

While optical communications across interstellar distances was initially thought impractical, military research has led to lasers sufficiently powerful to make such signalling much more efficient than any radio beacon.

Nuclear-powered lasers on the drawing boards could produce pulses that would outshine the sun by a factor of 10,000, said Harvard University physicist Paul Horowitz, who has already been searching for such pulses. He has designed a new telescope that will soon be dedicated full-time to that search.

And other innovative ideas keep coming along. Planet hunter Geoffrey Marcy of the University of California, Berkeley, said someday we may learn to use the sun itself as a gravitational-lens telescope, with a detector parked at its focal length of 500 astronomical units.


David L Chandler
Click to expand...

http://www.newscientist.com/news/news.jsp?id=ns99996255

Which does make me think even more that we seem to be working on assumptions about the way aliens might do things given such a wide rnage of potential evolutionary trajectories. What if 10 years down the line we suddenly think "hold on what if they were doing it this way?" and we tweak the detectors and lo and behold we'd been getting the signals all along.

fluffle said:
let's just hope they see el dorado, or a couple of minutes of MTV.
Click to expand...

Thats what worries - Vogons may be the worst poets in the galaxy but even then they may be affroned by that and destroy the planet out of principle!!
 
Just a thought but I (and others) have been a bit suspicious of Ananova for a while and I wonder if this report is really delivering the story straight or complete enough to get a rounded point of view?

Fairs fair Emps, they did get the crux of the story.
 
fluffle said:
...

let's just hope they see el dorado, or a couple of minutes of MTV.
Click to expand...
They're probably already building a Deathstar, just for us. :eek!!!!:
 
I've always been of the opinion that if intelligent alien races pick up our broadcasts, then they'll watch a bit of news, decide that we must be some of the most barbaric and unpleasant beings in the universe, and avoid us like the plague.
;)
 
This, of course, is working on the assumption that there are intelligent civilisations out there. I find it odd that no-one ever considers that we might be the most advanced civilisation in the universe at the moment, and all the UFO stories are wide of the mark (extra-dimensional beings as opposed to extra-terrestrial). It certainly would be a turn up for the books if it were the case. Here we are waiting for some kind of reply, when all the other planets out there are at an equivalent Stone Age level or similar.
 
We might detect other civilizations' radar scans for asteroids, space navigation beacons they've set up for their own use, or communications aimed at a probe they've sent our way. Seems to me any of these are more likely than a deliberate attempt to contact us.
 
i think there's a huge leap often made in assuming that if there are other intelligent civilisations out there they are going to be similar enough to us to be interested in doing anything remotely familiar to us. we assume that they will be sending out or picking up radio signals (intentionally or otherwise), maybe even building spaceships and the like. but the only thing we are absolutely guaranteed they will be interested in is reproduction!
 
fluffle said:
but the only thing we are absolutely guaranteed they will be interested in is reproduction!
Click to expand...

They are coming to steal our women!:eek:

No, I know what you mean, but do you think all intellegent life reproduces. Could it not develope as some sort of imortal planet (or molecular cloud) wide entity.
 
have you guys heard of the theory of mathematically working out the likelihood of life in the universe?
I think i read it in Bill Bryson Short History Of Nearly Everything

It went something like you work out average number of stars, then the probability they have planets, then the probability they have life supporting planets, then the probability of them supporting life, then intelligent life, then contact, etc etc
But basically it works out, because the Universe is so vast, that at least a million species are out there.

Dont quote me on those figures but its something along those lines, so lets all be optimistic eh!:p
 
jacksondavies19 said:
have you guys heard of the theory of mathematically working out the likelihood of life in the universe?...
Click to expand...

The equation is:
N = R* • fp • ne • fl • fi • fc • L

It's called the Drake equation devised by the astronomer Frank Drake (whose comments triggered) this thread, whose been a long time enthusiast for SETI.

There's and explanation of what it all means at the SETI Institute site:
http://www.seti.org/seti/seti_science/Welcome.html

I wonder about quite how valid it is as a lot of the values are little more than guesses.
 
the equation is rendered rather unhelpful by the fact that fl, fi, fc and L are completely unknown. it's an interesting idea but any value of N calculated is totally unreliable.

R* =The rate of formation of stars suitable for the development of intelligent life.

fp = The fraction of those stars with planetary systems.

ne = The number of planets, per solar system, with an environment suitable for life.
Click to expand...
these we can make some kind of estimate or educated guess about - we have SOME data.

fl = The fraction of suitable planets on which life actually appears.

fi = The fraction of life bearing planets on which intelligent life emerges. For more information, please visit Dr. William Calvin's "The Drake Equation's fi"

fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
Click to expand...
these could be anything from close to 0 (only our planet in the whole universe bearing a technologically-advanced civilisation) to 1 (all suitable planets in the universe bearing a technologically-advanced civilisation). we've only examined one suitable planet in enough detail to know, making these values totally inaccurate.

L = The length of time such civilizations release detectable signals into space.
Click to expand...
again, we have only ourselves as an example, and we can't even get an estimate from that. we've been releasing detectable signals into space for about 100 years but nobody has any idea when we will finish.
 
the value of fp has gone up a lot recently since the detection of the first extrasolar planets. Planets seem to be turning up every where. Also, in the current new scientist there is an article suggesting that the formation of large moons, like our own, which stabalise a planets spin may be quite common too.
 
You must log in or register to reply here.
Back
Top