lecture18 - Astronomy 3 The Nature of the Universe...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Astronomy 3: The Nature of the Universe Professor Alice Shapley Lecture 18: Cosmology (NGC 1499 Image credit: Markus Noller, Deep Sky Images)
Image of page 1

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

View Full Document Right Arrow Icon
Logistics Final exam: Monday, June 6 th , 11:30 am – 2:30 pm. Location: Fowler A103B. Most important : bring a #2 (i.e. normal) pencil. Recommended: bring a calculator. Scantrons will be provided. Review session for final exam: – This Thursday, June 2 nd , 6-8 pm. Location: MS 4000A (i.e. lecture hall). Sheet of useful formula and numbers will be provided along with final exam.
Image of page 2
Logistics Exam will have a mixture of multiple choice, matching, and true/ false, and will contain 90 questions, worth 1 point each. Exam will emphasize material on Measurements of Stars, Stellar Life Cycles, Stellar Remnants, Black holes, The Milky Way, Galaxies, Cosmology. This new material corresponds to lectures 12-18. The relevant reading from the textbook is: Chapters 15, 16, 17, 18, 19, 20, 22. There will also be material from the first part of the class on the exam, corresponding to Lectures 1-11, and Chapters 1-11, 13, 14. A few questions will be based on Labs.
Image of page 3

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

View Full Document Right Arrow Icon
Review from Last Time The Milky Way Galaxy: major components, motions, dark matter. The Galactic Center: black hole! Galaxy types.
Image of page 4
Edge-on, our galaxy looks like a flattened “disk” of stars with a central concentration or “bulge” of stars. Note the location of the Sun, very far from the Center. The disk is 1,000 light-years thick but 100x that in width – very thin! • Primary features: disk, bulge, halo, globular clusters. • Useful distance unit for Milky Way: kiloparsec (kpc) = 1000 parsecs ~3000 light years.
Image of page 5

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

View Full Document Right Arrow Icon
Orbital motions in the Milky Way Sun’s orbital period 250 million years v rot =220 km/s Disk has differential rotation. 1. Disk: Nearly circular rotation 2. Halo: Random, elliptical
Image of page 6
Deriving Mass of the Galaxy from its ( non-Keplerian ) Rotation Only interior mass affects rotation. (Like our solar system)
Image of page 7

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

View Full Document Right Arrow Icon
Dark Matter Most of the mass in the Milky Way galaxy: – Does not radiate – Is not ordinary “baryonic” matter, such as protons, neutrons, electrons On bigger scales (clusters of galaxies) dark matter fraction even higher. – Over 80% of matter is dark
Image of page 8
The Black Hole at the Galactic Center What lies at the center of our Milky Way Galaxy? In the direction of the constellation Sagittarius, our Galactic Center hosts a supermassive black hole (~4x10 6 M sun ). We can weigh the black hole at the Galactic Center by following the orbits of stars in its vicinity and using Newton/Kepler’s laws to infer how much mass must be there. One of the most convincing pieces of observational evidence for a black hole! Note: separate from issue of dark matter in Milky Way!
Image of page 9

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

View Full Document Right Arrow Icon
Galaxies: summary • What are the three major types of galaxies?
Image of page 10
Image of page 11
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