the picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces....
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![Page 1: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/1.jpg)
• The picture showsa) 2 galaxies that are orbiting each other and which are
distorted by tidal forces.b) One peculiar galaxy with 2 bright knots in its centre and
2 tails extending in opposite directions.c) 2 clouds in our Milky Way which have radiation jets and
are forming clusters of stars.
![Page 2: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/2.jpg)
Lecture 9 Phys 1810 • Last Class– Kepler’s Laws of Planetary
motion 2.5, 2.8• This class
– Weighing the sun, Box 2-3– Box 2-2, including escape velocity – introduction to General Relativity
p. 595-598– Radiation 3.1 to 3.4
• Coming Up– Radiation 3.4, 4.1,4.2, 4.3, 18.4 &
3.5, etc.
Test on Friday in class.
• Handout about the test on the website.• Tests are based on material in class; use textbook index to select the relevant topics to read in the book. NOT just the pages or sections that I write down. NOT the whole chapter.• Try multiple choice questions on website.
• Office hour at 1pm Monday. Come and ask me questions about the test or practice math.
![Page 3: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/3.jpg)
velocity = distance / time. For each area in the above case:• time is the same for each area.• distance == distance travelled on the elliptical path == length of the red arc.So the planet’s velocity is proportional to the distance travelled.
The planet’s largest velocity is associated with which area (A, B, or C)? At the largest velocity is the planet at its closest or furthest approach from the sun?
![Page 4: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/4.jpg)
![Page 5: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/5.jpg)
Keplerian Orbit
When most of the mass is in the centre of a system (e.g. our solar system) then the velocity of the orbiting objects decrease with radius from the centre.
What does the graph look like?
For systems where most of the mass is in the centre. Does it work for galaxies? (Learn later.)
![Page 6: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/6.jpg)
• For an orbit: Force of Inertia = Force of Gravity
Weighing the Sun
![Page 7: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/7.jpg)
![Page 8: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/8.jpg)
![Page 9: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/9.jpg)
![Page 10: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/10.jpg)
![Page 11: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/11.jpg)
![Page 12: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/12.jpg)
• General Relativity: Gravitational Lensing
![Page 13: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/13.jpg)
Material on test is up to here.
![Page 14: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/14.jpg)
![Page 15: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/15.jpg)
At the scale of atoms, we use the description of light as particles (photons).At the macroscopic, everyday scale, we use a wave description of light.
![Page 16: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/16.jpg)
![Page 17: The picture shows a)2 galaxies that are orbiting each other and which are distorted by tidal forces. b)One peculiar galaxy with 2 bright knots in its centre](https://reader036.vdocuments.net/reader036/viewer/2022081520/56649d5a5503460f94a3adf9/html5/thumbnails/17.jpg)
Will start here next class.