1 / 6

Astronomy and Cosmology week 3 – Thursday 17 April 2003 Gravity

Astronomy and Cosmology week 3 – Thursday 17 April 2003 Gravity. Star Date Gravity lecture and applications Workshop : moons of Jupiter break Minilecture by Geoff and Jonathan Friday: workshop report on Moon Friday: take Quiz 3. Guiding Questions.

romney
Download Presentation

Astronomy and Cosmology week 3 – Thursday 17 April 2003 Gravity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Astronomyand Cosmologyweek 3 – Thursday 17 April 2003Gravity • Star Date • Gravity lecture and applications • Workshop: moons of Jupiter • break • Minilecture by Geoff and Jonathan • Friday: workshop report on Moon • Friday: take Quiz 3

  2. Guiding Questions • How did ancient astronomers explain the motions of the planets? • Why did Copernicus think that the Earth and the other planets revolved around the Sun? • What did Galileo see in his telescope that confirmed that planets orbit the Sun? • How did Tycho Brahe attempt to test the ideas of Copernicus? • What paths do the planets follow as they move around the Sun? • What fundamental laws of nature explain the motions of objects on Earth as well as the motions of the planets? • Why don’t the planets fall into the Sun? • What keeps the same face of the Moon always pointed toward the Earth?

  3. Derive Kepler’s 3d law from Newton’s second law: F=ma Gravitational force acceleration in circular orbit F=GmM/r2 a = v2/r Solve for v2: Speed v = distance/time = 2pr/T. Plug this into v2 and solve for T2: This is Kepler’s third law: T = period and r = orbit radius.

  4. Applying Kepler’s 3d law: For objects orbiting the Sun, a=radius in AU and p=period in years A satellite is placed in a circular orbit around the Sun, orbiting the Sun once every 10 months. How far is the satellite from the Sun?

  5. Sidereal and Synodic periods: A satellite is placed in a circular orbit around the Sun, orbiting the Sun once every 10 months. How often does the satellite pass between the Earth and the Sun?

  6. We can use Newton’s gravity to approximate the size of a black hole! Not even light can escape (v=c) if it is closer than r to a black hole. This is the Schwarzschild radius: R=_____________________

More Related