| Type of Radiation | Wavelength (nm) | Temperature
(K) | Typical Sources |
| gamma-rays |
<0.01 |
>108 |
no sources; some gamma-rays produced in nuclear reactions |
| X-rays |
0.01-20 |
106-108 |
gas in clusters of galaxies; supernova remnants; solar
corona |
| UV |
20-400 |
104-106 |
supernova remnants; very hot stars |
| Visible |
400-700 |
103-104 |
stars |
| Infrared |
103-106 |
10-103 |
cool clouds of dust and gas; planets; satellites |
| Radio |
>106 |
<10 |
no objects this cold; emission produced by electrons moving in
magnetic fields |
