Seeing the Universe

All these different kinds of radiation begin down in the sub-atomic world when an electron, depicted here in yellow, hits a proton, blue, or suddenly changes direction... and releases a bundle of energy known as a "photon"-those glowing bursts of energy.


Photons, in fact, are light-and all the different kinds of radiation we mentioned are in reality just photons with different energies.


Different temperatures and environments typically produce photons with different energies.

X-rays, for example, get made when temperatures are very high, millions of degrees, and gravity is very strong...

And the different energies need diffferent detectors to see them.


Scientists think of light as a stream of particles with specific energies, but photons in fact behave both as particles and as waves.


So they can also be described in terms of the distance between the crests of each wave... and that's called "wavelength."


Let's step through the spectrum and see how energies change, resulting in the different kinds of radiation.



Electromagnetic Spectrum
The electromagnetic spectrum explained in simple terms using real-life examples.

Imagine the Universe
An introduction on the electromagnetic spectrum including why we need to go into space to see the entire spectrum.

Electromagnetic Spectrum
This site explains each type of electromagnetic radiation, its uses and the dangers from too much exposure to the radiation.

Interactive Multimedia Adventures for Grade-school Education Using Remote Sensing (IMAGERS)
A simple explanation of electromagnetic radiation including each type of radiation, how we "see" using that type of radiation and what that type of radiation shows us.

NASA's Observatorium
An introduction to the electromagnetic spectrum.

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