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Optical SETI ideas

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LAN_403

Conundrum

Fri Feb 01 2013, 10:10PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Hi all.

Just had an interesting idea, after my recent experiments with IR sensitivity in solar panels.

It seems that the "dark time" on solar panels for 7 hours a day would make an ideal time to detect infrared laser signals from up to a few light years away, by combining the weak signals from many solar panels over a large area of the UK.
Such a system could be installed along with existing lightning suppression systems for low cost.

It appears that a simple coupling capacitor pair of about 1000uF at 10KV going to a high speed amplifier powered from a small battery would be enough to detect such weak signals and simply relay them via radio to a USB stick.

Has anyone else ever tried anything like this?

Another related idea is to use solar panels to detect and trigger a camera in order to record "red sprites" and other interesting atmospheric phenomena by looking for the sudden peak and slow decay curve.

Daedronus

Fri Feb 01 2013, 10:40PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

I don't think anyone will deliberately use radio or laser to attempt interstellar contact. Kinda pointless considering the timescale.
If we do receive something it will probably some accidental transmission.

And unless there is some form of practical FTL everything is pretty pointless,we are doomed to die on this little rock....eventually.

I would really like to see some form of FTL in my lifetime, if it's not possible this universe is kinda stupid, this whole universe is big and great but it could just as well not be there because anything outside the solar system is 100% unreachable.

Conundrum

Sun Feb 17 2013, 04:02PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Not entirely accurate, we might intercept a signal sent accidentally in our direction if it is from a kardashev type 2 to another kardashev type 2 civilization.
don't forget about stellar drift, a lot of the time scintillation could occur due to debris at the edge of each system so its not completely hopeless.

-A

Ash Small

Sun Feb 17 2013, 04:20PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Daedronus wrote ...

And unless there is some form of practical FTL everything is pretty pointless,we are doomed to die on this little rock....eventually.

"Although the Sun will continue to shine for billions of years Earth will be uninhabitable in roughly 1 billion years this is because as the Sun ages it gets hotter and brighter and in about 1 billion years the temp on Earth will be too hot for liquid water to exist on the surface."

Mars could be habitable within the next billion years, either way, we'll have to escape this solar system at some point, but why do we need FTL? Surely conventional spacecraft could reach somewhere suitable eventually? It will, after all, only be a 'one way' trip.

Conundrum

Mon Feb 18 2013, 08:43AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

I still say that it would be a trivial exercise to tie all those thousands of square metres of solar cells in the UK together and make an optical SETI phased array.
It wouldn't be perfect but it might be good enough.

-A

Uspring

Mon Feb 18 2013, 02:02PM

Registered Member #3988 Joined: Thu Jul 07 2011, 03:25PM
Location:
Posts: 711

Daedronus wrote:

I would really like to see some form of FTL in my lifetime, if it's not possible this universe is kinda stupid, this whole universe is big and great but it could just as well not be there because anything outside the solar system is 100% unreachable.

Sadly the universe doesn't seem to have been created in order to please us humans.

While, by contemporary physics, FTL travel looks unlikely, I wouldn't give up yet. Physics is not done, the most glaring problem being the inconsistency between general relativity and quantum mechanics. String theorists are attempting to reconcile these, but as yet have AFAIK not come up with any idea, what would be possible in the real world if their efforts would succeed.

Conundrum

Wed Jul 24 2013, 07:04PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

See

Also the same setup could be used to receive optical amateur radio signals, with the addition of a simple polarising filter and two diodes to filter out ambient noise.

Another worthwhile hack, harvesting the ultrabright diodes from broken optical mice as these are exceptionally efficient at 100mA pulsed and can be ganged in 10s as a phlatlight replacement.

Sulaiman

Thu Jul 25 2013, 12:31PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

The capacitance of solar cells is so high that above a feq Hz there's nothing,
also noise levels are high, as are leakage currents.....

Conundrum

Sat Jul 27 2013, 09:37AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

OK, thanks for that Sulaiman.

I did wonder about the capacitance issue, there is a workaround if a simple resistor is used to discharge the capacitance peridodically at say 50Hz, any signal will show up in the quiet periods.

This approach synchronised to the mains frequency would also reduce interference, and provide an effective way to distinguish a true signal from someone's 4G phone etc.

-A

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