Assignments
• Watch Cosmos: Possible Worlds, Episode 11, "The Fleeing Grace of the Habitable Zone".
• Submit questions, comments, or items you want to discuss, using the form at the bottom of this or any page at Discuss Cosmos: Possible Worlds.
• more to come
To think about
• Compare the challenges of long-distance space travel with those of the Polynesians' travels into the unknown.
• How does general relativity promise a way to use the Sun as an objective lens for a powerful telescope?
• What is the "water hole" in the electromagnetic spectrum, and why is it important in the search for exterristrial intelligence?
• Is there a paradox in the notion of settling far out in space around another star, then using that new "Sun" as a lens to see our Sun and Earth's past? What is the key to this apparent paradox?
• About that "cosmic telescope": In what realms of the electromagnetic spectrum would it "see"? (Brings new meaning to the term 'achromatic' !!)
• Are there any fundamental limitations to the resolution of a "cosmic telescope"?
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Questions for Discussion
Student questions will appear here
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This episode is interesting but like most of the episodes leaves one asking what is the data? We have an opportunity to watch our best NASA and JPL scientists try to uncover answers to a very interesting question about the habitability of early Mars as Mars2020 lands on Feb. 18th. You hear sound bites about Mars conditions for having been in the habitable zone 3-4 million years ago but that also leaves you wondering how to put it in perspective. Ray Arvidson is a professor of Planetary Sciences at Wash. U in St.Louis and a lecturer on Viking Cruises - so he knows how to make sense of his subject for us. Here is the link to a lecture on "Viking TV" that explains what has been found by the Curiosity rover (his project) and gives you a background for following Mars2020 Perseverance:
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Gale posts a link to SETI. From reading that page I note that the best listening we can do with FAST (the Chinese fixed radio telescope like - but bigger than Arecibo - is 28 light years out. This link shows the size of the "Local Group" of galaxies with the Milky Way at its center:
https://upload.wikimedia.org/wikipedia/commons/1/1c/Local_Group_and_nearest_galaxies.jpg
If you zoom in you see that we are talking Millions of light years in radius and this is only the local group. So, even though the odds favor intelligent life given the immensity of the Universe, we can't know much about it radiowave-wise. Am I correct about this?
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What might a "sun lens telescope" look like? Where would the focal point be? How could images be stored, combined and "de-blurred"?
(Mentioned in this video, just in case you've curious: Making an Aragoscope.)
Cody mentions the Veratasium video discussing Agrogo's discovery of the bending of light around a perfectly smooth circle or sphere. He does not mention the magnification but it is still pretty good:
https://youtu.be/y9c8oZ49pFc
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Things you did not know about shadows:
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Is this week's episode purely based on a hypothesis that thousands of years from now people could board a starship and go in search of livable places to live in constellation Alpha Centuri? Isn't that just a fantastic story??
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How do we know that ancient people of China moved to the Hawaiian islands? How can that be proven? Did they use DNA to help give them the answer??
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Would any world with the right combo of ingredients for human colonization not also likely be already settled with life? By settling there wouldn’t we be replaying the ills of colonialism?
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29 Legendary Scientists Came Together in the “Most Intelligent Photo” Ever Taken.
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How long will the process of expansion of the sun into a red giant last, before its contraction begins? "A couple hundred million years" was mentioned during the episode, but it wasn't entirely clear what that reference meant.
[[ from GR: See THIS and THIS. ]]
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Other Resources
