NATS 1740 Lecture Notes - Lecture 8: Astronomical Object, Blueshift, Refraction

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Radu Campeanu

Document Summary

Lecture 8 - observing the macro - universe. How to see a bee 1000 km away. Light can be thought as a wave motion. The distance between two successive wavecrests is the wavelength. The number of wavecrests per second is the frequency. The height from crest to trough is the amplitude. Reflection: when a beam of light hits the surface of a medium of higher density. Refraction: when a beam of light passes from air into glass or water it is bent. The shorter the wavelength the greater the refraction and this provides the dispersion of light in prisms/lenses. The dispersion of light by a prism is called a continuous spectrum (like the rainbow). The blue component of light is refracted most and the red the least. Observations of the absorbtion spectrum of an astronomical object tell us the atomic/molecular composition of a star, or a planet, or a cloud of gas.