ASTR 101 Lecture Notes - Lecture 21: Stratospheric Observatory For Infrared Astronomy, Nuclear Weapons Testing, Very-Long-Baseline Interferometry

• School: Queen's University
• Department: Physics, Engineering Physics and Astronomy
• Course: ASTR 101
• Professor: David Alan Hanes

Document Summary

Astronomers use all wavelengths of light because they want to study all sources that can be identified in the sky. Radio emissions = can see clouds of gas in milky way. X-rays = can see very hot sources. Historical order of wavelengths: radio radiation, infrared sources, x-rays, then gamma rays. Very long, which means that radio photons carry very little energy. Used to study very cool sources (i. e. not emitting visible light. Example: hydrogen gas in the galaxy (h is the most abundant element in the universe) Discovery of radio radiation came serendipitously in the hands of karl jansky. Set him the task of figuring out why there was static in telephone lines in the 1930s. Conclusion was it came from three sources: (1) nearby lightning strikes, (2) diffuse far-away storms, and (3) radiation from the milky way. Since did not work at a university, couldn"t follow this discovery up.