You are welcome. Stars are like a noisy transmitter. The
Sun sends out RF that we can pick up on radio receivers here
with almost no difficulty. There is Sun noise all the way from
HF to daylight. Daylight is just Sun noise you can see.

	Generally, the higher we go in frequency, the more Sun
noise we pickup.

	There were people back in the 1700's who theorized that
there were energies that we could not see that behaved like
light but that was just weird speculation that had no real value
until a fellow by the name of Sir William Frederick Hershel who
lived in England did an interesting experiment in 1800.

	He was an astronomer and musician who built telescopes
and generally contributed a lot to astronomy by cataloging
stars.

	He was originally trying to figure out how much heat
different colors of sunlight had so he used filters of varying
colors and eventually a prism to break sunlight in to a spectrum
or rainbow of all its colors.

	His test devices were thermometers whose bulbs had been
blackened with lamp black. He would hold a thermometer in a
certain color of light and see how much it went up compared with
a control thermometer which was sitting outside the spectrum.

	His big discovery occurred when he found that he could
move the thermometer past the red end of the rainbow and it went
up higher than any other color even though one could not see
any sort of light.

	If you want to read more, do a Google search for
discovery of infrared. That was the first article that came up.

	There is a quote I have read by somebody whose name
escapes me that says, "Let's be thankful for the things we have
and also for other things we don't have."

	What I am getting at is what else we get from the cosmos
and our Sun.

	That broad spectrum electromagnetic radiation we get
from the Sun and other stars includes everything from
ultraviolet through X-rays. We do get some of the ultraviolet
which is how we get sunburn and skin cancer but things could be
a whole lot worse.

	Our atmosphere blocks the X-rays and some of the
ultraviolet which is why people are concerned about the ozone
hole. The ozone layer way up there near the outer edge of our
atmosphere is sort of like a big Sun glass lens that shields us
fromX-rays and other cosmic rays that would positively cook our
geese very nicely if we ever were directly exposed.

	When ten meters is alive with F2 propagation in Winter,
we now know that the Earth got blasted with X-rays from the Sun.
X-rays cause the ion density to increase in the F2 and other
layers and make DX on ten and six meters possible. If you were
an astronaut doing a space walk, however, you would want to go
inside and maybe even come back to Earth if it got bad enough.

	The Solar Flux readings we get from WWV are Sun noise at
10.8 GHZ. If you hear them talk of an X-ray event, that is X-ray
flux and we can hope for ten and 6 to pop wide open.

	Before I stop, here, I must remind anyone who is
interested that Sporadic E can be very spectacular on ten and
six meters but that seems to be triggered by some other
mechanism that is not fully understood. It's not X-ray flux and
it can hit at night as easily as it does during the day.

Martin

Phil Scovell writes:
> Martin,
> 
> Thanks for those details.  Makes sense now that you put it that way.  
> Thanks
> for sharing those details.