1.13 Astro 1 - Astro 1 Section 1 Professor Brandt Wednesday...

Info icon This preview shows pages 1–2. Sign up to view the full content.

Astro 1, Section 1, Professor Brandt Wednesday January 13th 1999 Announcements: Lecture notes: How big is the Universe? How small are we? Demonstration of how to find the Big Dipper Title of class We will cover atoms (5x10 -9 cm) to galaxies (1x10 23 cm) 100 000 000 000 000 000 000 000 cm in a big galaxy want a way to write down very large numbers without all the zeroes --called scientific notation To use scientific notation count the zeroes Examples: 10cm = 1 x 10 1 cm 100 cm = 1 x 10 2 cm 1000cm = 1 x 10 3 cm Million stars in glob cluster = 1000000 stars = 1x10 6 stars for 2 billion stars = 2x10 9 for 2.5 billion stars = 2.5x10 9 Now we also want to be able to do simple math with scientific notation to get relative sizes radius of earth is 6x10 8 cm radius of solar system is 6x10 14 How many times bigger is radius of solar system than the radius of the earth? =1x10 6 Simple rule is 10 a /10 b = 10 (a-b) in the above example 14-8 = 6 so 1x10 6 solar system radius is about a million times larger than the
Image of page 1

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

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: earth's radius A few more useful numbers • distance to nearest star = 4x10 18 cm • size of a galaxy = 3x10 22 cm • distance to nearest galaxy = 2x10 23 cm So how much bigger is the distance to the nearest galaxy as the size of our galaxy 2x10 23 / 3x10 22 = 2/3 x10 1 = 6.6 Scale model of solar system Earth is 1/10 of a cm in size The solar system is the size of campus Where is the nearest star? about the distance to Los Angeles Discuss Video Lots of distances in that video In this course you will learn how people actually measure those giant distances Today we'll start with a well known method to astronomers called parallax Parallax = a method for finding the distances to fairly nearby objects like planets and some stars. Far away objects move less. Astronomers use the same effect with 2 telescopes to determine distances...
View Full 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