Radio Waves / Gamma rays etc.

Thread Starter

Nathan Hale

Joined Oct 28, 2011
156
Hi everyone! I was wondering why is it that radio waves can penetrate the earths atmosphere but other rays dont?
I also once watched a sci channel program in which the narrator said how certain stars "hiding " behind galactic dust ( something like that ) can be "seen" in the infrared spectrum but not in the normal visible light spectrum. my question is how are the infrared rays and their wavelengths able to break through certain stuff while visible light is stopped from passing through the dust? is there a relationship between wavelength and the density/ makeup of things they are trying to penetrate?
 
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radiohead

Joined May 28, 2009
508
Gamma "rays" aren't rays, but particles of energy. In the radioactive sense, alpha and beta particles can't pass through a brown paper bag, but gamma can pass through paper with very little effort. Gamma can evan pass through lead. It will lose some or most of its energy, but it will still pass through lead. See the website below for more info.

For asking your question, I hope you have an interest in physics.
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html
 

nsaspook

Joined Aug 27, 2009
7,279
Yes Gamma photons are energetic photon particles but Gamma "rays" are waves in the classic electromagnetic sense like "radio" wave. Their wavelengths are so small that they interact with matter on a scale similar in size to atomic particles and pass through the mainly empty space between them. I have several devices at work that could easily generate Gammas from non-radioactive sources if I was crazy, disables the hardware/software interlocks and accelerated a low AMU beam to a few MeV.

 

Thread Starter

Nathan Hale

Joined Oct 28, 2011
156
So you are saying that the reason certain wavelengths pass through dust/ matter is because of the empty space between the atoms or the molecules?
 

nsaspook

Joined Aug 27, 2009
7,279
So you are saying that the reason certain wavelengths pass through dust/ matter is because of the empty space between the atoms or the molecules?
It's a lot more involved than that, absorption can vary due to weight of the nuclei, total mass per area in the path(thick atmosphere), resonances in molecules , the presence of magnetic or electric fields (ionosphere, magnetosphere) and other factors that shield us from high energy waves/particles.

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970718.html
 
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KL7AJ

Joined Nov 4, 2008
2,225
Hi everyone! I was wondering why is it that radio waves can penetrate the earths atmosphere but other rays dont?
I also once watched a sci channel program in which the narrator said how certain stars "hiding " behind galactic dust ( something like that ) can be "seen" in the infrared spectrum but not in the normal visible light spectrum. my question is how are the infrared rays and their wavelengths able to break through certain stuff while visible light is stopped from passing through the dust? is there a relationship between wavelength and the density/ makeup of things they are trying to penetrate?
Ultraviolet and X-rays dissipate most of their energy in the ionization of the air molecules. Lower frequencies don't have the energy to create ionization, so pass through essentially unaffected.
 
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