Lecture7 Light - Light and Telescopes We will learn much...

Info icon This preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Light and Light and Telescopes Telescopes We will learn much about the objects in distant space by decoding their cosmic message (light!). To do this, we must first understand the properties of light and how light works. Begin to develop your working conceptual model for how light & matter interact: + basic properties of light + E&M spectrum of radiation
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Why are we talking about light? All the information we have about Universe comes from light. We can’t do direct experiments like in other sciences. Have to learn how to decode light, like a fingerprint. Need to understand how light is created and what it can tell us. How do light and matter interact? What we really want to know is what objects out in space are made of and what their properties are.
Image of page 2
Why are we talking about light? Light is a medium of cosmic communication. Telescopes are the means by which we gather light (cosmic messages). Galileo pointed first telescope to the sky and suddenly became aware of the abundance of naked-eye (few K to 10K stars) unseen stars (10 times as many)! Hubble space telescope did wonders in enhancing our knowledge and sparking our curiosity!
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Matter can emit light, absorb light, reflect (or scatter) light, and transmit light. emission - produce light, radiate (loose) energy absorption - absorb light, gain energy reflection/scattering - light bounces off transmission - let light pass through How do light & matter interact?
Image of page 4
Reflection vs Scattering A mirror reflects light in a particular direction. A movie screen scatters light in all directions.
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Interactions of Light and Matter A. emit B. absorb C. reflect/scatter D. transmit
Image of page 6
Why is a red rose red? A. The rose emits red light. B. The rose transmits red light. C. The rose absorbs red light. D. The rose reflects red light. Survey Question
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Why is a red rose red? A. The rose emits red light. B. The rose transmits red light. C. The rose absorbs red light. D. The rose reflects red light. Survey Question
Image of page 8
White light and spectra Until Newton it was believed that white is fundamental color of light. • The colors of the rainbow, were believed to be added as white light went from one medium to another. • Newton performed experiments that disproved this belief. • He started by passing a beam of sunlight through a glass prism.
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Spectrum (Isaac Newton’s experiments) WHITE light (or sunlight) separates (splits) into a sp ec tr u m of 6 colors (indigo is not considered separate color in astronomy) Then Newton selected a single color and sent it through a second prism. What happened? Dispersion: the phenomenon by which a ray of light splits into its constituent colors, when passes through a transparent medium Spectrum: the band of colors obtained due to the dispersion of light (spectra, plural).
Image of page 10
?
Image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern