Notices
Results 1 to 6 of 6
Like Tree2Likes
  • 1 Post By RamenNoodles
  • 1 Post By Gere

Thread: Are we able to detect the entire electromagnetic spectrum?

  1. #1 Are we able to detect the entire electromagnetic spectrum? 
    Forum Ph.D.
    Join Date
    Jan 2013
    Posts
    932
    Can the ends (or the entire) of the electromagnetic spectrum that cannot be detected by equipment/instruments?

    Do electromagnetic wavelengths longer than radio waves exist? How about smaller than gamma rays? Or are those the limits that light has?

    Does official documentation assume that we have detected the entire electromagnetic spectrum?

    Or are there parts that we cant detect whatsoever(or at least with modern day equipment)?

    Or is the previous question nonviable, as: if we cant detect it, we can't assume that those parts of the electromagnetic spectrum does not exist?

    Is there a definite answer to this question?

    I have a problem with post #12 in this thread Is there any meaning in the Bible verse "faith is the substance of things hoped for the evidence of things not seen" makes any sense?
    about "Faith being evidence of the invisible science" and this post is talking about some kind of invisible EMF thingy...


    sir ir r aj likes this.
    Quote Originally Posted by jocular View Post
    If thy right nipple offend thee, pluck it off! Goes for the other, too!
    Reply With Quote  
     

  2.  
     

  3. #2  
    exchemist
    Join Date
    May 2013
    Location
    London
    Posts
    3,683
    Quote Originally Posted by RamenNoodles View Post
    Can the ends (or the entire) of the electromagnetic spectrum that cannot be detected by equipment/instruments?

    Do electromagnetic wavelengths longer than radio waves exist? How about smaller than gamma rays? Or are those the limits that light has?

    Does official documentation assume that we have detected the entire electromagnetic spectrum?

    Or are there parts that we cant detect whatsoever(or at least with modern day equipment)?

    Or is the previous question nonviable, as: if we cant detect it, we can't assume that those parts of the electromagnetic spectrum does not exist?

    Is there a definite answer to this question?

    I have a problem with post #12 in this thread Is there any meaning in the Bible verse "faith is the substance of things hoped for the evidence of things not seen" makes any sense?
    about "Faith being evidence of the invisible science" and this post is talking about some kind of invisible EMF thingy...
    Well, at the bottom end (low frequency), this Wiki article gives you an idea of the challenges: Extremely low frequency - Wikipedia, the free encyclopedia

    Seems 3Hz is about as low as anyone can measure - though one can conceive, mathematically, of any arbitrarily low frequency below this.

    At the top end, i.e. frequencies higher than gamma rays, in principle one can again conceive, mathematically, of any arbitrarily high frequency, i.e. a wavelength as short as you like, but in practice I don't think there is any oscillator in the universe producing anything above gamma rays.

    There's more about the range of the EM spectrum here: Electromagnetic spectrum - Wikipedia, the free encyclopedia

    (I
    'd ignore that posting you refer to. That poster can't even spell "visible", let alone string together a coherent argument. Obviously the visible range of the EM spectrum is a tiny fraction of the total that we can detect, but so what?)


    Reply With Quote  
     

  4. #3  
    Forum Sophomore
    Join Date
    Aug 2013
    Posts
    193
    Quote Originally Posted by exchemist View Post
    At the top end, i.e. frequencies higher than gamma rays, in principle one can again conceive, mathematically, of any arbitrarily high frequency, i.e. a wavelength as short as you like, but in practice I don't think there is any oscillator in the universe producing anything above gamma rays.
    Such high energy photons usually originate by decaying of other high energy particles. It is not unusual to have particles with energy as high as EeV and particles with energy as high as 8 joules were detected. These particles usually originates in some brutal processes like supernova. If some particle like pion gets this kind of energy it will relatively soon decay into 2 gamma.
    sir ir r aj likes this.
    Reply With Quote  
     

  5. #4  
    KJW
    KJW is offline
    Forum Professor
    Join Date
    Jun 2013
    Posts
    1,691
    It's worth mentioning that in principle one can have photons that are as high or as low energy as we please simply by travelling arbitrarily close to away from or towards the source of photons, applying the Doppler effect to the photons.
    There are no paradoxes in relativity, just people's misunderstandings of it.
    Reply With Quote  
     

  6. #5  
    Forum Ph.D.
    Join Date
    Jan 2013
    Posts
    932
    Quote Originally Posted by KJW View Post
    It's worth mentioning that in principle one can have photons that are as high or as low energy as we please simply by travelling arbitrarily close to away from or towards the source of photons, applying the Doppler effect to the photons.
    Isn't light peculiar in the law of relativity, and that the only thing that the velocity of the observer doesn't affect the speed of electromagnetic waves(photons in this case)?

    Since the speed of light doesn't change, but will the energy(wave displacement) actually change?

    Here's a link of what i mean Theory of relativity - Wikipedia, the free encyclopedia
    • The speed of light is nonetheless invariant, the same for all observers.
    Quote Originally Posted by jocular View Post
    If thy right nipple offend thee, pluck it off! Goes for the other, too!
    Reply With Quote  
     

  7. #6  
    KJW
    KJW is offline
    Forum Professor
    Join Date
    Jun 2013
    Posts
    1,691
    Quote Originally Posted by RamenNoodles View Post
    Quote Originally Posted by KJW View Post
    It's worth mentioning that in principle one can have photons that are as high or as low energy as we please simply by travelling arbitrarily close to away from or towards the source of photons, applying the Doppler effect to the photons.
    Isn't light peculiar in the law of relativity, and that the only thing that the velocity of the observer doesn't affect the speed of electromagnetic waves(photons in this case)?

    Since the speed of light doesn't change, but will the energy(wave displacement) actually change?

    Here's a link of what i mean Theory of relativity - Wikipedia, the free encyclopedia
    • The speed of light is nonetheless invariant, the same for all observers.
    The Doppler effect changes the frequency of the light and hence the energy of the photons as seen within given frames of reference. Because light does have the same speed for all observers, the speed of the light can't be used to differentiate between the various frames of reference in which the energy of the photons could be measured. Therefore, all photons regardless of their frequency are essentially identical in that (for example) a gamma photon in one frame of reference is a radio frequency photon in another frame of reference... same photon, different energies.
    There are no paradoxes in relativity, just people's misunderstandings of it.
    Reply With Quote  
     

Similar Threads

  1. electromagnetic spectrum question
    By fatman57 in forum Physics
    Replies: 5
    Last Post: January 30th, 2010, 06:26 PM
  2. Electromagnetic Spectrum Frequency Changes
    By Brokenazs in forum Electrical and Electronics
    Replies: 7
    Last Post: August 28th, 2009, 08:17 AM
  3. Electromagnetic spectrum questions
    By gs99 in forum Physics
    Replies: 7
    Last Post: July 8th, 2009, 02:08 AM
  4. Replies: 3
    Last Post: March 22nd, 2006, 04:59 AM
  5. Electromagnetic Spectrum
    By guilleermo in forum Physics
    Replies: 6
    Last Post: October 5th, 2005, 12:57 AM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •