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Moondust Against Global Warming?

A group of scientists from the University of Utah has proposed that we collect dust from the moon and spray it into space near the first Earth-Sun Lagrange point, where it would linger for about two years and block about 2% of the sunlight that reaches us. While it would probably reduce the global average temperature, it would not remove carbon dioxide, which has its own negative effects, such as ocean acidification and shifting precipitation patterns. Similar plans have previously been put forward for giant mirrors in space, fleets of reflecting satellites, and earth-sized air conditioning units. We have a video coming up on this in a few weeks.

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Why Do We Only Get Older and Not Younger?

Last year in September, shortly after the publication of my book “Existential Physics”, I did an interview for Big Think about some topics in the book. The one about entropy has now appeared on YouTube.

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Chinese Researchers Create a Plastic-Metal

Plastics have taken over the world by being durable and easy to mold, but they make miserable conductors. This is sometimes desired, but sometimes not. A group of Chinese researchers have now found a way to attach nickel atoms to polymers to create a conductive plastic. Paper here, press release here.

Comments

Anonymous

The Lagrange Moon Dust idea sounds pretty cool but also potentially hazardous to future astronomy instruments as well as being a great name for an experimental ambient noise music album.

Anonymous

I think that the moondust idea is too smart by half. Trying to band-aid over the business as usual that caused the problem is no solution. We aren't going to fix global warming by 'engineering' a solution except by developing the integral fast reactor to commercial scale and then using its capacity to start the hydrogen era. Oh, and perhaps sequestering some of that carbon, reducing human population, replacing our extractive economy with a sustainable one, etc.

Anonymous

Regarding time's arrow, why couldn't it simply be that time does in fact only flow forward? Why is entropy seen as being necessary if forward time is reality? Regarding entropy, why is entropy 'small' in the plasma of the Big Bang and 'larger' when matter coalesces later? I've always had trouble understanding thermodynamics, among other things.

Anonymous

I am not sure how many MDs adhere to it, but the idea of "do no harm" seems to be one that is universally applicable.

Anonymous

I think the reason that physicists try to explain why time has a direction is because all of our favorite equations are time reversible. So, what breaks the symmetry and causes time to only flow in one apparent direction -- entropy. If we lived in a universe in which time's arrow was intrinsically one-sided (no "cause"), then the equations that we discovered that describe the universe should have an intrinsic one-sidedness time direction as well. Or, at least, that's my read on the situation.

Anonymous

Tracey, Happy Thursday! I understand why physicists try to explain time's arrow with entropy, but it very well could be that time is fundamental, that it only progresses into the future, regardless of what math implies. Math is after all, only a tool for modeling reality and therefore if time is fundamental and only progresses into the future then the mathematical model needs to change to reflect reality. IMO, this may be one of those 'lost in math' situations.

Anonymous

IMO, the problem is that too many people think that we can tech our way out of the problems that tech and human nature got us into. They ignore the human nature part of the cause in their proposed solution.

Anonymous

Because the temperature was near infinite, so by the thermodynamic definition, S=Q/T, the entropy was infinitesimally small for any finite amount of heat sloshing around. This of course is a gross oversimplification and hardly intuitive. I am just reciting a definition, which doesn’t necessarily correspond to an intuitive understanding. In fact, this topic leads to one of the most heated exchanges in the Feynman lectures: https://www.feynmanlectures.caltech.edu/I_46.html. Listen to the audio starting at the 56 minute mark. Section 46-5 at the end of the chapter provides the context. Keep in mind that this was recorded in 1962. That’s two years before the CMB was detected! The idea of a single point of origin and expansion of the universe had been percolating but it was hardly established science. Feynman once again does a fantastic job teaching the audience how to think like a physicist. He was a master of the subject and seemed to have thought about every possible problem!

Anonymous

Rad, Happy Thursday! Very interesting stuff. I just don't get entropy, from that lecture: "Order is not order in the sense that we like the arrangement, but in the sense that the number of different ways we can hook it up, and still have it look the same from the outside, is relatively restricted." I read a book by a physicist, British I believe, who argued that entropy hadn't increased, but decreased as where we once had plasma, we now have order in the form of planets, stars, etc. This doesn't seem to correlate with what Feynman says, which seems to me to be that absolute disorder, from S=Q/T, is actually low entropy. I gave up on thermodynamics because of ideas like that, not intuitive at all to me. I have my issues. I looked the book up in my borrowed records from my library and it wasn't there, so I can't tell you its title. I was hoping to have it as a reference. Maybe later. One more thing. My mom bought me the Feynman Lectures on Physics paperback book set when I was in high school in the 70s and it wasn't cheap. Now I see that it's all online for free! I won't tell my mom.

Anonymous

Hear you on the thermo/stat mech. Not intuitive. He has some things to say about entropy in Chapter 44, maybe that helps. We have come a long way indeed. Not only are they free to access now but you can hear the lectures as they were delivered. Listening to Feynman talk about physics is a visceral experience I can never get enough of. That debate with a grad student or could even be another faculty member was sooo good.

Anonymous

What I find interesting is his New York accent. I haven't read his lectures in a while, so I may as well read those books again. I bet I'll still have no luck with thermo though.

Anonymous

Another issue with entropy: As posted by Rad under my initial post, S = Q/T, entropy is very small at the very high temperature at the Big Bang, S tends to 0. However, it would be infinite, S tends to infinity at T = 0, after the 'heat death' of the universe when T will be 0 degrees K, everything is at the energy ground state. I don't understand thermodynamics and this entropy thing because it is not intuitive. I need help, like a new born baby.

Anonymous (edited)

Comment edits

2023-03-31 21:37:23 This won’t help, but it might entertain https://youtube.com/watch?v=j5Ths1bpQdQ&si=EnSIkaIECMiOmarE
2023-02-17 22:03:01 This won’t help, but it might entertain https://youtube.com/watch?v=j5Ths1bpQdQ&si=EnSIkaIECMiOmarE

This won’t help, but it might entertain https://youtube.com/watch?v=j5Ths1bpQdQ&si=EnSIkaIECMiOmarE