On Aug 30, 3:08 pm, "Mike Kaliski" wrote:
"Radium" wrote in message

ps.com...



Hi:

What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?

Thanks,

Radium

Radium

As the article suggests, higher frequencies are considered as being in the
infra red wavelengths of light, so 3,438 GHz can be considered to be at the
upper limits of radio frequency astronomy.

Visible light, ultra violet light, x-rays and gamma rays are all
electromagnetic waves at higher frequencies and are also used for astronomy
observations and experiments. Satellites are generally used to observe in
the ultra violet, x-ray and gamma ray spectrums as these wave lengths are
largely absorbed by the earth's atmosphere.

Remember, there are no strict cut off frequencies where one type of
electromagnetic wave becomes another type. Radio merges into infra red which
merges into visible light, ultra violet, x-rays and so on. Any limits are
purely arbitary ones applied by humans in order to categorise the way in
which electromagnetic waves of a certain frequency can be expected to
behave.

Look at a colour palette. It is easy to pick out the primary colours.
Everyone who isn't colour blind can pick out red, blue, green, yellow etc.
But where do you draw the line to decide where red becomes green, blue or
yellow? The colours slowly merge from one to another just as the
characteristics of radio waves change as frequency increases.

Mike G0ULI

Sorry, I meant to ask whether 3,438 GHz is the highest radio frequency
used to receive audio signals from outer space. I should have made my
question more specific. Radio-astronomers study sounds from the sun as
well as visual data.

I wonder if a space station with a 3,438 GHz AM receiver could pick up
any extremely-distant audio signals between 20 to 20,000 Hz [from
magnetars, gamma-ray-bursts, supernovae and other high-energy but
cosmic objects] after demodulating the 3,438 GHz AM carrier wave.