How can low energy light be detected if it's too weak to knock out an electron?

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Discussion Overview

The discussion revolves around the detection of low energy light, particularly long wavelength light that lacks sufficient energy to eject electrons. Participants explore how such light can be detected and the implications of its energy levels on absorption and existence.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question how scientists detect long wavelength light if it cannot knock out electrons, raising concerns about the light's ability to cease to exist.
  • One participant draws an analogy between the operation of a radio and the behavior of low energy light, suggesting that the interaction of waves with magnetic fields can induce currents similar to how electrons are knocked out.
  • Another participant explains that the electric field of a wave can accelerate free electrons in a metal, inducing electric currents, but also notes that these electrons can lose energy through scattering, leading to thermal motion and resistance.
  • There is a suggestion that interstellar telescopes function similarly to radio antennas, converting incoming signals into visual information.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the detection of low energy light and the mechanics of radio operation. There is no consensus on how low energy light can be absorbed or detected, and the discussion remains unresolved with multiple viewpoints presented.

Contextual Notes

Participants exhibit uncertainty about the mechanisms of light detection and the interactions of electromagnetic waves with matter. Some assumptions about the behavior of electrons and the nature of light are not fully explored.

Who May Find This Useful

This discussion may be of interest to individuals exploring concepts in physics related to light, electromagnetic waves, and their interactions with matter, as well as those curious about radio technology and its applications in astronomy.

Jarfi
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A long wavelength light has too little energy to knock out electrons, so how do scinetists detect them? and how does a light with low energy ever cease to exist since it can never be absorbed?
 
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Jarfi said:
A long wavelength light has too little energy to knock out electrons, so how do scinetists detect them? and how does a light with low energy ever cease to exist since it can never be absorbed?

Do you know how a radio works?
 
DrDu said:
Do you know how a radio works?

I have taken a look at it, but don't fully get it, something about the magnetic field of the wave pushing current..but then I just thought, to push a current is kind of like knocking out electrons, since they are jumping from their atoms.

oh but to push a current the wave needs to behave like a wave and interact with its magnetic field with the metal atoms, without collapsing, but waves interacting behave as particles? now I'm just more and more confused.
 
The wave accelerates the electrons in a metal due to their electric field, i.e. electric currents are induced. The electrons in a metal are not bound to any specific ions but can move freely. However the accelerated electrons can also scatter from the atomic cores and thus loose the energy they received from the electric field creating thermal motion of the atoms, i.e. heat. That's the reason for the resistance of metals.
In a radio, basically the currents induced are used to move the membrane of the loud speakers. This also diminishes the current as the energy of the currents is converted into sound waves.
 
DrDu said:
The wave accelerates the electrons in a metal due to their electric field, i.e. electric currents are induced. The electrons in a metal are not bound to any specific ions but can move freely. However the accelerated electrons can also scatter from the atomic cores and thus loose the energy they received from the electric field creating thermal motion of the atoms, i.e. heat. That's the reason for the resistance of metals.
In a radio, basically the currents induced are used to move the membrane of the loud speakers. This also diminishes the current as the energy of the currents is converted into sound waves.

so the interstellar telescopes are basically just giant radio-antennas who turn the information into pictures.
 
Jarfi said:
so the interstellar telescopes are basically just giant radio-antennas who turn the information into pictures.

Yep.
 

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