Doppler method stars light wavelength changes due to its slight orbital wobble

Doppler method stars light wavelength changes due to

This preview shows page 2 - 4 out of 5 pages.

Doppler method - star's light wavelength changes due to its slight orbital wobble i. Transit method - when a planet moves in front of its star it dims the starlight slightly ii. Many other methods! iii. Most have been detected by indirect means: At least 10% of sun-like stars have planets Confirmed and announced August 13, 2015 Distance 96 light years - "a young hot jupiter" 51 Eridani b - discovered December 2014 Our solar system is not alone! Comets: What we knew and what we can see now? Our system is near the Milky Way galaxy which has 200-300 billion star and is ~100,000 light years across It takes the solar system ~250 million years to orbit the center of the galaxy at 200 km/sec (125 miles per second) Is orbited by two small irregularly-shaped galaxies called the Large and Small Magellanic Clouds visible in the Southern Hemisphere Over 100 billion galaxies constitute the known universe We have gone from being the center of the universe to "a medium-sized planet orbiting around an ordinary star in the outer suburbs of an ordinary spiral galaxy" - Hawking, a Brief History of Time The nearest large galaxy Andromeda is 2.2 million light years away (light travels 6 trillion miles in a year) Our Solar System's Neighborhood Stationary car honking its horn. The sound waves are equidistant from each other on all sides Moving car honking. The sound waves are closer together in front and farther apart in back The Doppler Effect is integral to our modern understanding of how the universe formed: Change in wavelength causes change in pitch of the horn as the car passes Compressed light waves have a shorter frequency, a blue shift Stretched light waves have a lower frequency, a red shift In 1929, Edwin Hubble discovered that all galaxies have a red shift, meaning that they are all moving away from the Earth If they are moving away from each other, they were once much closer together Rewind the clock far enough and all matter would have been intensely compact in a This is what a star's simplified spectrum looks like a red shifted Hydrogen absorption line The Doppler Effect also effects light: Forming the Universe GSCI 1050 Page 2
Image of page 2
Rewind the clock far enough and all matter would have been intensely compact in a single space that later expanded These observations and inferences led to: The Big Bang Theory Predicted in 1948 - Alpher and Herman (Princeton) Holmdel antenna was designed to detect low levels of microwave radiation Could not "tune" the antenna to get rid of microwave background noise from every direction equivalent to a body radiating at approximately 2.7 degrees K Predicted as the residual temperature from the Big Bang Discovered in 1964-65 - Penzias and Wilson (Bell Labs) T0 = d/v, where velocity = distance to galaxy x hubble constant (H0) H0 is a known value based on observation, it equals 73 km/sec/Mpc T0 is the time when the two objects were next to each other, and can be found by
Image of page 3
Image of page 4

You've reached the end of your free preview.

Want to read all 5 pages?

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

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes