Re: Could you tell me about the cosmic ray wavelength and frequency?

The answer to this question is not necessarily very straight-forward.  
Most cosmic rays are particles, not photons and, as such, we tend to speak 
of them as having energy and not wavelength or frequency.  According to 
the physicist Louis de Broglie, even particles and matter have a 
wavelength, and the wavelength of a particle is equal to Planck's constant 
divided by the particle's momentum.  According to this relationship, an 
electron with an energy of 120 electron volts (eV) has a wavelength of 
about 112 pm (pico-meters, where 1 pm is equal to a millionth of a 
millionth of a meter).  To find a particle's momentum, you need to 
multiply the particle's mass by it's speed; sometimes this is fairly easy 
and other times it's fairly difficult.  In any event, cosmic ray particles 
have a wide range of mass and speed, so it makes more sense to talk about 
them in terms of energy instead of wavelength.

From an energy standpoint, cosmic rays have a tremendous variability.  In 
space near the Earth, most cosmic rays come from the sun because the sun 
is always emitting the solar wind.  The solar wind is a steady stream of 
particles driven into space because of their high temperature - almost 
like evaporation - and these particles permeate the entire solar system.  
When astronauts are in orbit, they receive some radiation from the solar 
wind, and the astronauts who went to the moon received even higher doses.  
Particles in the solar wind have energies of millions or tens of millions 
of electron volts (MeV) because they are usually travelling at speeds of 
up to 300 to 500 kilometers per second (about 200-300 miles per second).  
One electron volts is the amount of energy carried by a single electron 
that is carried by a 1-volt electric field.  So electrons in a 9-volt 
smoke detector battery have energies of 9 eV and electrons from a car 
battery have energies of about 12 eV..  This means that a single proton in 
the solar wind has an energy that is several million times as high as the 
electrons from a battery.  Although this seems like a lot of energy (and 
it is, on an atomic scale), a single high-energy proton is not dangerous.  
What's dangerous is when you have a LOT of these protons hitting you, and 
if you are exposed to the solar wind at the distance of the earth, every 
square centimeter is struck by over 400 million protons each second.  This 
is why space radiation can be dangerous.  However, cosmic radiation from 
the sun is not dangerous to us on earth because very little can penetrate 
our magnetic field and our atmosphere to reach the ground.

There are also cosmic rays from outside our solar system, and these are 
the ones we see the most on the ground because they are a LOT more 
energetic than solar cosmic rays.  Galactic cosmic rays (as they are 
called) are given off by supernova explosions elsewhere in our galaxy and 
they can travel through space at almost the speed of light for millions of 
years before they reach us.  Galactic cosmic rays can have energies that 
are so high that a single atom can carry as much energy as a fast 
baseball.  Part of this energy comes from the high speed of the particles -
 they are traveling just a whisker under the speed of light - and part 
comes from their mass, because they can be as heavy as iron atoms (up to 
50 times as heavy as particles in the solar wind).  These are not nearly 
as common as solar wind particles, but they account for most of the cosmic 
radiation dose we experience at the Earth's surface because they are more 
likely to penetrate the atmosphere to reach the surface.

For more information on cosmic radiation, you can look at the NASA and 
NOAA web pages; both have a lot of information about cosmic radiation 
and "space weather".  Good places to start are:
 http://www.sec.noaa.gov/ (NOAA space weather page) http://www.nasa.gov (you can perform a site search on the NASA home page 
using the terms "solar wind" and "cosmic radiation")

Both of these organizations can also give you access to a wealth of 
information from spacecraft in Earth orbit and elsewhere in the Solar 
System and, in fact, I used some of these data in some of my own research.