Assignments
• Watch Crash Course Big History #3, Sun and Earth
• Before each class, check the appropriate episode page(s) for Assignments, things To Think About, More Resources, and the day before class, check Your Questions. To be sure that your own question or comment influences my plans for the upcoming Monday class, submit it at least 24 hours beforehand (Sunday morning).
• Watch this video about star life cycles, and how they are represented by a Hertzsprung-Russell diagram:
These diagrams help scientists to estimate the distances to stars in a certain distance range. (Learn more in my summer 2021 course: That Star, How Far? at OLLI.)
• Watch this animation of the movement of continents from 540 million years ago to the present.
Scotese, C.R., 2016. Plate Tectonics, Paleogeography, and Ice Ages, (Modern World - 540Ma), YouTube Animation https://youtu.be/g_iEWvtKcuQ.
The time in millions of years ago (mya) is shown in the upper left corner of the display, and the name of the geologic period in the lower left.
• Watch this video introduction to vectors (don't be afraid!). Vectors will help us to understand why clouds of ordinary matter are pulled by gravity into disks, not spheres -- large clouds into galaxies, small clouds into stars and solar systems.
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To Think About
• What produces the pressure and heat that causes a star to begin the fusion of hydrogen to helium?
• How are first-generation stars different from stars of the second and later generations?
• If you study the flow of a stream near the bank or the edges of islands, you will find "eddies" where the water flows in circles instead of straight down the stream. There are also eddies in the circular flow of matter in a pre-stellar disk. What results from them?
• Why was Pluto "demoted" from planet to dwarf planet?
• Why do continents "drift"? Hint:
• What do the lgp (little green people) mean when they speak of Earth's "Goldilocks conditions" for life?
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More Resources
• Motions of stars in the Milky Way, our galaxy.
In this animation, time is looping back and forth from 57,000 years in the future to 357,000 years in the future (looping makes it easier to follow a particular bright object). All of the objects appear fixed in the sky to us now. How do you think this animation was made?
To learn more about this figure, click HERE.
• To learn more how scientists have come to understand the movements of Earth's crust, see How Scientists Know About Continental Drift and Plate Tectonics.
• For a listing of geological periods and their definitions, see the following diagram and consult Wikipedia: Geological period.
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Your Questions
On every page of this web site is a form where you can contribute questions, comments, or suggestions. Any contributions that pertain to this page will appear HERE. Shortly before each class, check Your Questions for the episode(s) assigned.
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Sent by email:
Telescope
by Louise Glück
There is a moment after you move your eye away
when you forget where you are
because you’ve been living, it seems,
somewhere else, in the silence of the night sky.
You’ve stopped being here in the world.
You’re in a different place,
a place where human life has no meaning.
You’re not a creature in a body.
You exist as the stars exist,
participating in their stillness, their immensity.
Then you’re in the world again.
At night, on a cold hill,
taking the telescope apart.
You realize afterward
not that the image is false
but the relation is false.
You see again how far away
each thing is from every other thing.
“Telescope” by Louise Glück from Averno. © Farrar, Straus and Giroux, 2006. Reprinted with permission in The Writer’s Almanac, Garrison Keilor, August 17, 2015
