A few simple questions:

1) Whats the exact value of Hydrogen line?
2) And under what condition(s) is this value holds true?

A few simple questions:

1) Whats the exact value of Hydrogen line?
2) And under what condition(s) is this value holds true?

Regards,
Jay Bala.

Lets take the hyperfine, appears to be a basic and simpler model,

c/f= gives just a little over 21 cm right?

Also, what is the measurement error of this frequency?

Considering the time (seconds) and length (meters) are man made
numbers, is there some measurements or ratios that expresses these
values where these units cancel?

Regards,
Jay Bala.


On Jul 13, 5:42 pm, Uncle Al <Uncle... at (no spam) hate.spam.net> wrote:

The "21 cm" hyperfine transition is 1.4204057517667 GHz.

The "natural width" is determined by Heisenberg Uncertainty

Jay Bala wrote:
Lets take the hyperfine, appears to be a basic and simpler model,

c/f= gives just a little over 21 cm right?

Also, what is the measurement error of this frequency?

Considering the time (seconds) and length (meters) are man made
numbers, is there some measurements or ratios that expresses these
values where these units cancel?

Regards,
Jay Bala.

On Jul 13, 5:42 pm, Uncle Al <Uncle... at (no spam) hate.spam.net> wrote:

The "21 cm" hyperfine transition is 1.4204057517667 GHz.

The "natural width" is determined by Heisenberg Uncertainty

delta E delta t => h/(4pi)

delta (h*f/2) * delta t => h/(4pi)

delta (f) * delta t => 1/(2pi)

delta t is the life time of the excited state
delta E is energy of transition

On Jul 18, 12:07 pm, Richard Saam <rds... at (no spam) att.net> wrote:
Jay Bala wrote:
Lets take the hyperfine, appears to be a basic and simpler model,
c/f= gives just a little over 21 cm right?
Also, what is the measurement error of this frequency?
Considering the time (seconds) and length (meters) are man made
numbers, is there some measurements or ratios that expresses these
values where these units cancel?
Regards,
Jay Bala.
On Jul 13, 5:42 pm, Uncle Al <Uncle... at (no spam) hate.spam.net> wrote:
The "21 cm" hyperfine transition is 1.4204057517667 GHz.
The "natural width" is determined by Heisenberg Uncertainty

delta E delta t => h/(4pi)

delta (h*f/2) * delta t => h/(4pi)

delta (f) * delta t => 1/(2pi)

delta t is the life time of the excited state
delta E is energy of transition

This doesn't sound right.

Delta t relates to the length of the wave train, hence the duration of
the transition, not the lifetime of the excited state, before it
relaxes.

Delta E relates to the spread of frequencies in the wave train, not to
the energy of the transition (which determines the centre frequency)

Chalky wrote:
On Jul 18, 12:07 pm, Richard Saam <rds... at (no spam) att.net> wrote:
Jay Bala wrote:
Lets take the hyperfine, appears to be a basic and simpler model,
c/f= gives just a little over 21 cm right?
Also, what is the measurement error of this frequency?
Considering the time (seconds) and length (meters) are man made
numbers, is there some measurements or ratios that expresses these
values where these units cancel?
Regards,
Jay Bala.
On Jul 13, 5:42 pm, Uncle Al <Uncle... at (no spam) hate.spam.net> wrote:
The "21 cm" hyperfine transition is 1.4204057517667 GHz.
The "natural width" is determined by Heisenberg Uncertainty

delta E delta t => h/(4pi)

delta (h*f/2) * delta t => h/(4pi)

delta (f) * delta t => 1/(2pi)

delta t is the life time of the excited state
delta E is energy of transition

This doesn't sound right.

Delta t relates to the length of the wave train, hence the duration of
the transition, not the lifetime of the excited state, before it
relaxes.

Delta E relates to the spread of frequencies in the wave train, not to
the energy of the transition (which determines the centre frequency)

In terms of the 21 cm hydrogen line,

http://en.wikipedia.org/wiki/Hydrogen_line#Cause_of_the_hydrogen_line

"This transition is highly forbidden with an extremely small probability
of 2.9E-15 /sec. This means that the time for a single isolated atom of
neutral hydrogen to undergo this transition is 1/2.9E-15 or 3.4E14 seconds"

from above:

delta f * delta t => 1/(2pi)

delta f * 3.4E14 => 1/(2pi)

delta f => 4.68E-16 Hz

The above observed significant digit frequency

1.4204057517667 GHz = 1,420,405,751.7667 Hz

Apparently other effects (doppler )
are broadening the width beyond the
natural lifetime Heisenberg uncertainty line width.

On Jul 29, 2:43 am, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
On Jul 27, 7:51 pm, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
The observed error margin is ~ 5 E-5
The theoretical error margin is ~ 5 E-16
Just as the theoretical error margin requires an emission time of ~ 10
million years, the same applies for the required detection time. The
difference between the 2 error margins is ~ E 11 corresponding to a
required detection time of ~ 1 hour. This sounds reasonable.
It would be interesting to know
if the observational error margin ~ 5 E-5 Hz
in the observed frequency of astrophysical hydrogen 21 cm
1.4204057517667 GHz = 1,420,405,751.7667 Hz
represents a limit
below which astrophysical electromagnetic frequencies
cannot be observed.
Are any electromagnetic waves observed below 5 E-5 Hz ?
In principle, yes, but we are now straying into areas of practical
eletronics. If it were possible to produce a sufficiently high Q tuned
filter to admit a still tighter pass band, then that would pick out
which ever frequency it was tuned to. However, you would still end up
with the pulse from fthe filter being ten times as long if the spread
was reduced by a factor of ten.
Yes "in principle" but such a long period
1/ 5 E-5 Hz = 20,000 seconds (333 minutes) (5.6 hours)
may be an extreme test of practical electronic instrumentation,

but given such practical electronic instrumentation:

Are any electromagnetic astrophysical waves observed below 5 E-5 Hz ?

Richard D. Saam

The point is that ALL frequencies within this range exist, via Fourier
analysis.
A 5.6 hour aperture for an astrophysical source would introduce
serious Doppler shifts due to the Earth's rotation. This would broaden
not narrow the spectrum (unless you, personally, are prepared to
finance a radio observatory at the South Pole)

Which brings up the point:

Chalky wrote:
On Jul 29, 2:43 am, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
On Jul 27, 7:51 pm, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
The observed error margin is ~ 5 E-5
The theoretical error margin is ~ 5 E-16
Just as the theoretical error margin requires an emission time of ~ 10
million years, the same applies for the required detection time. The
difference between the 2 error margins is ~ E 11 corresponding to a
required detection time of ~ 1 hour. This sounds reasonable.
It would be interesting to know
if the observational error margin ~ 5 E-5 Hz
in the observed frequency of astrophysical hydrogen 21 cm
1.4204057517667 GHz = 1,420,405,751.7667 Hz
represents a limit
below which astrophysical electromagnetic frequencies
cannot be observed.
Are any electromagnetic waves observed below 5 E-5 Hz ?
In principle, yes, but we are now straying into areas of practical
eletronics. If it were possible to produce a sufficiently high Q tuned
filter to admit a still tighter pass band, then that would pick out
which ever frequency it was tuned to. However, you would still end up
with the pulse from fthe filter being ten times as long if the spread
was reduced by a factor of ten.
Yes "in principle" but such a long period
1/ 5 E-5 Hz = 20,000 seconds (333 minutes) (5.6 hours)
may be an extreme test of practical electronic instrumentation,

but given such practical electronic instrumentation:

Are any electromagnetic astrophysical waves observed below 5 E-5 Hz ?

Richard D. Saam

The point is that ALL frequencies within this range exist, via Fourier
analysis.
A 5.6 hour aperture for an astrophysical source would introduce
serious Doppler shifts due to the Earth's rotation. This would broaden
not narrow the spectrum (unless you, personally, are prepared to
finance a radio observatory at the South Pole)

Which brings up the point:
 From where was the frequency range observed
(including the +/- 5 E-5 Hz)?
1.4204057517667 GHz = 1,420,405,751.7667 Hz

The fundamental question is:
What broadens the Heisenberg Uncertainty 5E-16 Hz  to 5E-5 Hz?- Hide quoted text -

Chalky wrote:
On Jul 29, 2:43 am, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
On Jul 27, 7:51 pm, Richard Saam <rds... at (no spam) att.net> wrote:
Chalky wrote:
The observed error margin is ~ 5 E-5
The theoretical error margin is ~ 5 E-16
Just as the theoretical error margin requires an emission time of ~ 10
million years, the same applies for the required detection time. The
difference between the 2 error margins is ~ E 11 corresponding to a
required detection time of ~ 1 hour. This sounds reasonable.
It would be interesting to know
if the observational error margin ~ 5 E-5 Hz
in the observed frequency of astrophysical hydrogen 21 cm
1.4204057517667 GHz = 1,420,405,751.7667 Hz
represents a limit
below which astrophysical electromagnetic frequencies
cannot be observed.
Are any electromagnetic waves observed below 5 E-5 Hz ?
In principle, yes, but we are now straying into areas of practical
eletronics. If it were possible to produce a sufficiently high Q tuned
filter to admit a still tighter pass band, then that would pick out
which ever frequency it was tuned to. However, you would still end up
with the pulse from fthe filter being ten times as long if the spread
was reduced by a factor of ten.
Yes "in principle" but such a long period
1/ 5 E-5 Hz = 20,000 seconds (333 minutes) (5.6 hours)
may be an extreme test of practical electronic instrumentation,

but given such practical electronic instrumentation:

Are any electromagnetic astrophysical waves observed below 5 E-5 Hz ?

Richard D. Saam

The point is that ALL frequencies within this range exist, via Fourier
analysis.
A 5.6 hour aperture for an astrophysical source would introduce
serious Doppler shifts due to the Earth's rotation. This would broaden
not narrow the spectrum (unless you, personally, are prepared to
finance a radio observatory at the South Pole)

Which brings up the point:
 From where was the frequency range observed
(including the +/- 5 E-5 Hz)?
1.4204057517667 GHz = 1,420,405,751.7667 Hz

The fundamental question is:
What broadens the Heisenberg Uncertainty 5E-16 Hz  to 5E-5 Hz