Part of spectrum viewed: Radio (wavelengths a lot longer than visible light).
Location: On the ground, as most radio waves get through the atmosphere.
Sources of radiation:
- Many radio waves in space come from cold clouds of hydrogen gas.
- Most stars do not give off many radio waves.
Image: A composite image of the Whirlpool Galaxy, using radio and visible light wavelengths. The white is how the galaxies appear to optical telescopes – one giant spiral galaxy with a smaller one hanging off an arm. The Very Large Array radio telescope array sees a much bigger picture. © B. Saxton (NRAO/AUI/NSF) with data provided by J. Hibbard, CC BY 3.0.