Suppose there are intelligent beings on a planet orbiting a star ten light-years away. Let us suppose that like us, they are not deliberately sending signals into space to draw attention to themselves, but like us, they are using a kind of SETI system to listen for signals from others. Coincidentally enough, their SETI system is incredibly similar to ours, with pretty much exactly the same capability of detecting signals.Chris Peterson wrote:An important, and often overlooked aspect of science, is that proof is not a requirement. The longer we search, and the more approaches we use (different frequencies, different sensitivities, different search protocols), the more information we have. That is, we don't just have a single piece of information, "no life detected", but we can have a lot of data which places constraints on what might be out there. For instance, we might say with near certainty that we know that there is no intelligent life on Star X which is using unfocused radio with a given power level and a given spectrum.Ann wrote:Like Owlice said, we can never prove a negative - that is, if we don't find anything at all, that doesn't prove much at all - so we can go on searching and searching and searching pretty much indefinitely without finding anything, and still say that we should go on searching.
They would not be able to pick up any broadcast TV/FM station.Ann wrote:
Suppose there are intelligent beings on a planet orbiting a star ten light-years away. Let us suppose that like us, they are not deliberately sending signals into space to draw attention to themselves, but like us, they are using a kind of SETI system to listen for signals from others. Coincidentally enough, their SETI system is incredibly similar to ours, with pretty much exactly the same capability of detecting signals.
Would they hear us?
If not, would they "almost hear us", or wouldn't they even come close to hearing us?
In other words, if there was a civilisation similar to ours ten light-years away, a civilisation that is not deliberately sending signals into space to call attention to themselves, what chances would we have to hear them?
I've also found that many of the links are dead. A search of the APOD archive shows that the same image, title, credit and explanation have been used as an APOD before, with the oldest definiite such use being the APOD of July 28 2002. It would seem that a previous use has been used again but the links in that were not checked to see if they were still active.NoelC wrote:Heh, the increased interest this image has caused must have shut down the servers - many of the links in the caption just don't work.
-Noel
They are not dead. The servers are just being temporarily stored in Hangar 18.owlice wrote:
The links were checked two days before this APOD went live; they worked then.
We've killed the servers!
http://mst3k.wikia.com/wiki/Hangar_18 wrote:
<<Shortly after the launch of a satellite from a space shuttle, the satellite collides with an UFO in front of the crew's eyes. Because of an upcoming election, some politicians try to hide the crashed UFO inside Hangar 18.
* Hangar 18 is a 1980 film that was released to capitalize on the UFO interest of the era. Although it flopped rather badly (reportedly earning a gross of only $6 million), it tantalized those who saw government cover-ups of UFOs (such as the Roswell incident) as dirty laundry needing to be aired.
Prologue: In one of the shortest host segments ever, Joel introduces the film, and then it's movie sign!
Segment One: A meteor shower is about to strike the Satellite of Love! Joel explains the tragic consequences if the hull is punctured and the ship loses its oxygen: "No more Kibbles n' Bots, and no mid-morning pleasure stimulations!" Crow tells him to lighten up.
Segment Two: Joel purges Crow's memory, dumping all non-essential remembrances.
"Every Punky Brewster episode? Dump! The Lyle Wagner Penile Implant Show? Dump!"
Segment Three: Joel taps into Crow's brain, and shows him his first memory--the moment when he was first turned on. In the bit, Joel explains that "CROW" is actually an acronym, which stands for "Cybernetic Remotely-Operated Woman." Crow, alarmed to discover that he's really female, begins to panic ("Thirtysomething is on! I need some chocolate!") until Joel reveals it's all a joke.
Segment Four: Joel announces that there are nearly 1,000 members in the fan club now,
and the 1,000th member will win "self satisfaction and a Demon Dog!">>
Segment Two: RJN purges Otto Posterman's memory, dumping all non-essential remembrances:lysandergray wrote:
I'm curious, why is this post/announcement identical to ones posted on 2004 March 7 and 2002 July 28?
They are perfect copies. Go to the APOD archive list and CTRL+F for "An Anomalous SETI Signal", you'll see what I mean.
owlice wrote:The links were checked two days before this APOD went live; they worked then.
We've killed the servers!
Pehaps ET has realised he/she/it has been detected and has acted to limit the news before we are attacked! 
Because APODs are sometimes repeated by design.lysandergray wrote:I'm curious, why is this post/announcement identical to ones posted on 2004 March 7 and 2002 July 28? They are perfect copies. Go to the APOD archive list and CTRL+F for "An Anomalous SETI Signal", you'll see what I mean.
That must be it!!!!DavidLeodis wrote:
I'd accept that if two of them didn't link to the exact same image.owlice wrote:Because APODs are sometimes repeated by design.
Weirrrrrrd!!!lysandergray wrote:I'm curious, why is this post/announcement identical to ones posted on 2004 March 7 and 2002 July 28? They are perfect copies. Go to the APOD archive list and CTRL+F for "An Anomalous SETI Signal", you'll see what I mean.
Weirrrrrrd reply.rstevenson wrote:It's common practice to repost previous APODs on the weekend. Nothing weirrrrrrd about it. The APOD masters have lives; they have time off; they are volunteers. Deal with your disappointment.
Rob
Interesting calculation. All stuff that's within our capabilities TODAY.neufer wrote:Ergo, at 10 light years: 10 bit/s communication would require directed communication with a 120 kw amplifier and a 42 m radio dish antenna.
Large parabolic reflectors are necessary for truly narrow focused beams in any event regardless of the source of the radiation. Masers have long been used as electronic amplifiers in radio telescopes and they are being developed as directed-energy weapons.NoelC wrote:Interesting calculation. All stuff that's within our capabilities TODAY.neufer wrote:Ergo, at 10 light years: 10 bit/s communication would require directed communication with a 120 kw amplifier and a 42 m radio dish antenna.
Out of curiosity, how "directed" is, for example, a maser beam (also doable today) vs. a radio dish antenna? Is the beam much tighter?
