Longest EM Wave Length: Man-Made or Natural?

[wolram]

A basic question i know, but what is the longest em wave length
man made or natural?

 

[MiGUi]

http://hypertextbook.com/facts/2001/RachelShapiro.shtml

 

[GENIERE]

A basic question i know, but what is the longest em wave length
man made or natural?

I’ve often wondered about this, years ago I asked a similar question “longest and shortest”. The latter possibly limited to the Planck length. The longest, I don’t think I got an answer. If and when the least massive particle is found, I suppose that will generate the lowest frequency. I recall reading lately about the galactic size wavelengths of “dark matter”.

 

[wolram]

by GENIERE
I've often wondered about this, years ago I asked a similar question "longest and shortest". The latter possibly limited to the Planck length. The longest, I don't think I got an answer. If and when the least massive particle is found, I suppose that will generate the lowest frequency. I recall reading lately about the galactic size wavelengths of "dark matter".
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Galactic sized wavelengths of dark matter sounds interesting, do
you have a link?
I was thinking about the time it takes to produce such waves and
the source.

 

[DaveC426913]

I was thinking about the time it takes to produce such waves...

That seems elementary. To produce a wave that's 100,000 light years peak-to-peak ... would take 100,000 years.

 

[GENIERE]

...Galactic sized wavelengths of dark matter sounds interesting, do you have a link?

http://www.sciam.com/article.cfm?articleID=00084A33-908A-111B-87CB83414B7F0000

 

[wolram]

Thanks GENIERE .

 

[Averagesupernova]

I am as we speak creating the worlds longest wavelength signal. I'll let you know when it completes its first cycle.