Elements And Electromagnetic Spectrum

[hazelm]

Using SETI, Giuseppi Cocconii and Philip Morrison were looking for the best way to listen for possible signals from some outer space source.  They decided that, if intelligent life "out there" was sending signals, their logical choice for method was electromagnetic waves. Needing to choose a frequency for listening, they settled in at 1420 MHz, the emission frequency of hydrogen.  I am sensing a connection between the spectrums of the elements, electromagnetic waves and radio waves.  Am I right?  Where might I find more about this?  I think my confusion comes out of the terms electromagnetic spectrum and electromagnetic waves (the latter not yet totally clear in my mind) and then radio waves.  Where might I read more about this?

[exchemist]

Using SETI, Giuseppi Cocconii and Philip Morrison were looking for the best way to listen for possible signals from some outer space source.  They decided that, if intelligent life "out there" was sending signals, their logical choice for method was electromagnetic waves. Needing to choose a frequency for listening, they settled in at 1420 MHz, the emission frequency of hydrogen.  I am sensing a connection between the spectrums of the elements, electromagnetic waves and radio waves.  Am I right?  Where might I find more about this?  I think my confusion comes out of the terms electromagnetic spectrum and electromagnetic waves (the latter not yet totally clear in my mind) and then radio waves.  Where might I read more about this?

You could try this, for an explanation of the connection between radio waves, microwaves and light. It's not too technical: https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html 

 

(The Wiki one is good but tends to assume a pre-exsting familiarity with a lot of scientific terms)

 

This hydrogen signal, known also as the "21cm line", as the radiation has a wavelength of 21cm, comes from the tiny difference in energy between two spin states of the hydrogen atom: one in which the spin of the electron is aligned with that of the nucleus and one in which the two spins are opposed to one another.

 

It was chosen because of the prevalence of hydrogen in the cosmos and the usefulness of examining 21cm radiation in astronomy. More here:  

https://en.wikipedia.org/wiki/Hydrogen_line

 

As for the connection between spectra of the elements and electromagnetic waves, what we mean by the spectrum of an element is the distinctive pattern of frequencies at which atoms of each element emits and absorbs EM radiation. These show up as lines in the spectrum. So yes, a spectrum is all about EM radiation.   More here: https://en.wikipedia.org/wiki/Spectral_line

 

These emissions and absorptions are caused by "resonances" between the frequency of the radiation and various modes of motion of the electrons in the atom. (It is found the electron in an atom behaves like a wave and it can only be stable in certain states, each of which a sort of standing wave pattern, like the harmonics on a violin string.) Accounting for the patterns of lines in atomic spectra was one of the early successes of quantum theory.  

Edited September 29, 2017 by exchemist

[hazelm]

You could try this, for an explanation of the connection between radio waves, microwaves and light. It's not too technical: https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html 

 

(The Wiki one is good but tends to assume a pre-exsting familiarity with a lot of scientific terms)

 

This hydrogen signal, known also as the "21cm line", as the radiation has a wavelength of 21cm, comes from the tiny difference in energy between two spin states of the hydrogen atom: one in which the spin of the electron is aligned with that of the nucleus and one in which the two spins are opposed to one another.

 

It was chosen because of the prevalence of hydrogen in the cosmos and the usefulness of examining 21cm radiation in astronomy. More here:  

https://en.wikipedia.org/wiki/Hydrogen_line

 

As for the connection between spectra of the elements and electromagnetic waves, what we mean by the spectrum of an element is the distinctive pattern of frequencies at which atoms of each element emits and absorbs EM radiation. These show up as lines in the spectrum. So yes, a spectrum is all about EM radiation.   More here: https://en.wikipedia.org/wiki/Spectral_line

 

These emissions and absorptions are caused by "resonances" between the frequency of the radiation and various modes of motion of the electrons in the atom. (It is found the electron in an atom behaves like a wave and it can only be stable in certain states, each of which a sort of standing wave pattern, like the harmonics on a violin string.) Accounting for the patterns of lines in atomic spectra was one of the early successes of quantum theory.  

Thank you for all those links.  I shall get to every one of them.  I did know why they chose hydrogen but not any of the rest.  As you said, it's a matter of not knowing enough about the scientific terms.  Goodness, even Google did not know "spectrum".  I asked for "definition" and got a page full of links to Charter Communications and other companies using the term.  Typical Google.  <G>

[exchemist]

Thank you for all those links.  I shall get to every one of them.  I did know why they chose hydrogen but not any of the rest.  As you said, it's a matter of not knowing enough about the scientific terms.  Goodness, even Google did not know "spectrum".  I asked for "definition" and got a page full of links to Charter Communications and other companies using the term.  Typical Google.  <G>

Well Google will know "spectrum" all right, but you would need a qualifier like "physics" with it to get rid of all the marketing with "spectrum" in it somewhere. 

 

Tell me, do you know a bit about the structure of atoms? The idea that electrons go into different orbitals two by two, and that as you go along the Periodic Table of Elements, each element has one more electron than the one before?  My 14yr old son is learning this in chemistry at school at the moment, so I imagine you may have done it at school yourself at some stage. If you do know about this, it makes understanding the spectra of atoms a lot easier. 

[hazelm]

Well Google will know "spectrum" all right, but you would need a qualifier like "physics" with it to get rid of all the marketing with "spectrum" in it somewhere. 

 

Tell me, do you know a bit about the structure of atoms? The idea that electrons go into different orbitals two by two, and that as you go along the Periodic Table of Elements, each element has one more electron than the one before?  My 14yr old son is learning this in chemistry at school at the moment, so I imagine you may have done it at school yourself at some stage. If you do know about this, it makes understanding the spectra of atoms a lot easier.

Right.  Eighth grade General Science.  I remember well.  We took the atom apart more than they seem to now.  We did not say "electrons and nuclei".  We said electrons and protons and neutrons.  We did, however, know the electrons were spinning around the nucleus of protons and neutrons.  We did not know how very creative they get in their dance. 

 

Am I allowed to tell this?  I'm not sure I should since I'll wager half the people around here have heard it before but it is my favorite memory of that class.  Take a chance?  Back before WW II, our science teacher stood before us and said "Some scientists think they can split the atom but they are wrong.  The atom is the smallest unit in the universe.  Than, a few years later, there came the horrible replacement of "Guns of August".  I always say I wonder where she was in 1945. 

 

Of course, the fault was not with the teacher.  Back then, it was a debatable topic.  Now we know.  And I often wish we did not.

Edited September 29, 2017 by Buffy
Fixed quoting

[exchemist]

Right.  Eighth grade General Science.  I remember well.  We took the atom apart more than they seem to now.  We did not say "electrons and nuclei".  We said electrons and protons and neutrons.  We did, however, know the electrons were spinning around the nucleus of protons and neutrons.  We did not know how very creative they get in their dance. 

 

Am I allowed to tell this?  I'm not sure I should since I'll wager half the people around here have heard it before but it is my favorite memory of that class.  Take a chance?  Back before WW II, our science teacher stood before us and said "Some scientists think they can split the atom but they are wrong.  The atom is the smallest unit in the universe.  Than, a few years later, there came the horrible replacement of "Guns of August".  I always say I wonder where she was in 1945. 

 

Of course, the fault was not with the teacher.  Back then, it was a debatable topic.  Now we know.  And I often wish we did not.

You were taught before WW2??

 

You must be around the age of my mother, who died last year. (My father is still with us, at nearly 90, in a nursing home.  I can talk to him about history, as it was his subject at university, but not physics. He could barely change a fuse.)  

 

Respect!

[Vmedvil]

Right.  Eighth grade General Science.  I remember well.  We took the atom apart more than they seem to now.  We did not say "electrons and nuclei".  We said electrons and protons and neutrons.  We did, however, know the electrons were spinning around the nucleus of protons and neutrons.  We did not know how very creative they get in their dance. 

 

Am I allowed to tell this?  I'm not sure I should since I'll wager half the people around here have heard it before but it is my favorite memory of that class.  Take a chance?  Back before WW II, our science teacher stood before us and said "Some scientists think they can split the atom but they are wrong.  The atom is the smallest unit in the universe.  Than, a few years later, there came the horrible replacement of "Guns of August".  I always say I wonder where she was in 1945. 

 

Of course, the fault was not with the teacher.  Back then, it was a debatable topic.  Now we know.  And I often wish we did not.

 

 

Things were much less complex back then I would have loved if atoms could never have been split personally,  less math. Here I am about to link a picture of the standard model of all "Smaller than atom interactions". I am sure you can begin to understand why I wish that. 

 

 

If you would like you can take a look at the equations for the SNF "Strong Nuclear Force" and WNF "Weak Nuclear Force" that me and Exchemist have been discussing in another thread and how complex they are, but yeah....... "What has Science done!" 

 

Here is the math of a hydrogen wave function, those dances of the electrons get very complex in math very quickly.

 

Edited September 30, 2017 by Vmedvil

[hazelm]

You were taught before WW2??

 

You must be around the age of my mother, who died last year. (My father is still with us, at nearly 90, in a nursing home.  I can talk to him about history, as it was his subject at university, but not physics. He could barely change a fuse.)  

 

Respect!

Bless his heart.  I know you treasure him.  A story about that.  I don't know if it is true.  An elderly man was in hospital.  Doctor came in and asked him, among other questions, "who is our president?"  The man looked at doctor for a minute and said "I don't know".  Doctor wrote on his chart that the man was senile.  Later, a nurse saw the note and asked doctor why he would say such a thing.  She told doctor that she and that patient visit ever day and talk about old times, famous people and happenings. "Why he is a wealth of information.  I learn a lot from him."  Doctor said patient didn't even know who is president.

 

Later the nurse went in to talk with the patient.  "Why," she asked, "did you tell doctor you don't know who the president is.  I know you do."  Patient looked at her and said, "Honey, at my age, who cares?"

[exchemist]

Bless his heart.  I know you treasure him.  A story about that.  I don't know if it is true.  An elderly man was in hospital.  Doctor came in and asked him, among other questions, "who is our president?"  The man looked at doctor for a minute and said "I don't know".  Doctor wrote on his chart that the man was senile.  Later, a nurse saw the note and asked doctor why he would say such a thing.  She told doctor that she and that patient visit ever day and talk about old times, famous people and happenings. "Why he is a wealth of information.  I learn a lot from him."  Doctor said patient didn't even know who is president.

 

Later the nurse went in to talk with the patient.  "Why," she asked, "did you tell doctor you don't know who the president is.  I know you do."  Patient looked at her and said, "Honey, at my age, who cares?"

Very true. He's had 2 strokes, can't walk and has trouble speaking clearly. But he's much better when a topic interests him, e.g. rugby or history.  I got a short dissertation on the influence of Thomas Aquinas on Mediaeval thought, a few months ago. I had come across Aquinas's tomb in Toulouse and mentioned it. 

 

Revenons a nos moutons, as they would no doubt say in Toulouse, is there anything else on the spectra of the elements, or is that enough for the time being?  

[hazelm]

Very true. He's had 2 strokes, can't walk and has trouble speaking clearly. But he's much better when a topic interests him, e.g. rugby or history.  I got a short dissertation on the influence of Thomas Aquinas on Mediaeval thought, a few months ago. I had come across Aquinas's tomb in Toulouse and mentioned it. 

 

Revenons a nos moutons, as they would no doubt say in Toulouse, is there anything else on the spectra of the elements, or is that enough for the time being?  

Thank you.  That is enough for the time being.  I went through it once but need to repeat and think.  Today was not a day for thinking,  at least not for thinking new ideas.    I'll try tomorrow.

Edited September 30, 2017 by hazelm

[hazelm]

A friend told me that Carl Sagan wrote a book in which he discussed the spectrum, EM waves, light, etc - what is discussed above. .  Would that have been "Cosmos"?  I once had that book but no longer have. 

[exchemist]

A friend told me that Carl Sagan wrote a book in which he discussed the spectrum, EM waves, light, etc - what is discussed above. .  Would that have been "Cosmos"?  I once had that book but no longer have. 

I'm afraid I don't know Cosmos. But there are lots of places you can read about the EM spectrum.  

[Buffy]

Both the original (Sagan) and new (deGrasse-Tyson) versions of Cosmos are on youtube. Here's the original:

 

https://www.youtube.com/watch?v=QH8O6AItdZ4

 

And the book is available in paperback for about $15: https://www.amazon.com/Cosmos-Carl-Sagan/dp/0345539435

 

 

 

The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses, :phones:

Buffy

[hazelm]

Thank you, Buffy.  I learned yesterday that I'd sent Carl Sagan's to a friend.  I'll get another copy and/or also Neill deGrasse Tyson's.  The latter is very easy reading.

Edited October 2, 2017 by hazelm