3 replies to this topic

[Karlis]

www.newsday.com said:

Leaders at the SETI Institute in Mountain View, Calif., are seeking assistance to sort through floods of signals coming into an array of radio telescopes in the Sierra National Forest. Read more...

[bison]

I began participating in the SETI Live project when it began, near the end of February.  One goes to their website, http://setilive.org ,  registers, reads the introductory tutorial materials, and begins to see the data from the Kepler field planetary systems, and other extra-solar planetary systems. This is in the form of 'waterfall' displays, which are time/frequency spectrograms.

We are asked  to look for straight line features, within a speckled field of mostly random radio emissions, and mark them with the interactive display, as explained in the tutorial. These straight line features denote technologically produced radio emissions. Most of these are due to our own radio traffic, but there is always the chance that an extraterrestrial signal will be found.

I've found that as one works with this system, they are gradually able to discern fainter and fainter signals. It is these faint signals that are of the greatest interest, as they are thought likeliest to have made the extremely long trip from another solar system.

[PeacefulAnarchy]

I'm no expert in these fields, but a couple of things have always puzzled me about SETI.

How do we know other life forms are using the same forms of communication as we are?

If there was a civilisation which could transmit back and they were say 100 light years away, wouldn't it take 200 years for us to receive a response?

Please don't tear a strip off me if I have this wrong, as I've said, I'm no expert in this field.

[Waspie_Dwarf]

PeacefulAnarchy, on 10 May 2012 - 09:02 AM, said:

I'm no expert in these fields, but a couple of things have always puzzled me about SETI.

How do we know other life forms are using the same forms of communication as we are?

We don't, but if they are using something we haven't discovered yet we can't look using that, so we are left with the forms of communications we do understand, electromagnetic radiation.. radio and optical. Since the science behind these are the same everywhere the advantages and disadvantages of different wavelengths will be the same for an extraterrestrial race as it is for us, giving us some idea where to search.

PeacefulAnarchy, on 10 May 2012 - 09:02 AM, said:

If there was a civilisation which could transmit back and they were say 100 light years away, wouldn't it take 200 years for us to receive a response?

Yes, if they were to respond to a message we sent now.
An extraterrestrial race 100ly away would just be picking up news of the sinking of the Titanic, they would have been aware of out existence for a few years (Marconi's first transatlantic radio transmission was in 1901). If an extraterrestrial race a 100ly away has responded to our early radio transmissions, their message to us could already be on the way, maybe arriving as soon as 2101.

PeacefulAnarchy, on 10 May 2012 - 09:02 AM, said:

Please don't tear a strip off me if I have this wrong, as I've said, I'm no expert in this field.

They were good questions.