[Q&A+] Colouring the Sun Green, Self-Sustaining Space Station, Fate of LUVOIR | Q&A 306

The case of Kary Mullis drug addled low level tech, who figured out PCR, didn't bother to write the paper, and got the Nobel anyway... Great episode on Veritasium https://youtu.be/zaXKQ70q4KQ?si=UwUf8_nSFLWVs4y7

When it comes to watching YouTube to get a Nobel Prize, if that worked, I would have already won the Masters. My contribution to science is the identification of the RBAF. RBAF stands for the Reasoning by Analogy Fallacy. Okay, maybe just the RAF. I am convinced that RAF is a widespread phenomenon. Unfortunately, it is almost always wrong. Now I am not Terrance Howard, but based on zero research and zero evidence, I think I am right. I eagerly await my induction into the ranks of Nobel winners.

Hello how is your crypto life going?

About the environmental problems linked to the mega-constellations, you told a lot in a very short time. I'd like to had some points or nuance some things you said : - about the magnitude. Yes the natural impact of all that falls on Earth is still orders of magnitude higher than what we send and what comes done from our activities. But there are two caveats : 1- the plan for these mega-constellations, if implemented, implies an increase several orders of magnitude of what we have done since Sputnik. It's tens of thousands of satellites which would fall every year (they are suppose to last between 3 or 5 years before being de orbited and replaced). Remember there are at least 5 mega-constellations being produced or in project (not only Starlink) ; 2- what comes down naturally is a mix of very different things : rocks, metals, etc. which are never pure. What the satellites are made of are very specific materials with a high degree of purity. The impact cannot be the same. - Are we condemned to repeat our errors? with climate change, we knew and we reacted too late (even if we stopped all CO2 emissions today, we would be around +2 degrees for thousands of years). Shouldn't we do something else this time? It would be especially easy because it's not a systemic problem like CO2. It's more like what we did with CFCs : a sociaety with or without mega-constellations is not very different than a society with them. All that just to have a ping a bit shorter? - There is another concern besides the impact of reentries on the Ozone layer : it's water. Water release in the Troposphere is not a problem because, with the cycle of water, the concentration in the atmosphere stays the same. Water in the mesosphere stays in the mesosphere. Water is a very potent greenhouse gas and every rocket put a little more water in the mesosphere : imagine if we multiply the quantities by several orders of magnitude... In conclusion : there should be more talks and more studies about that.

"Self-sustaining" comes down to your definition. It's easy to imagine a durable biological community in orbit, but solar panels eventually need to be replaced, as do specialized EVA gear, electronic components, and actual structural components. On Earth we have a global web of manufacturing and supply industries along with vast quantities of raw material just under our feet and the energy to make it all work. The ultimate limiting factor on orbit would almost certainly be fuel to reboost or avoid collision.

Was the rocket lab proposal for the Mars sample return accepted?

On the subject of couch problem-solving, something I think about almost daily is how to help the homeless, the jobless, those who have faltered and can't get themselves back up. Am I wrong to think that this problem is not too expensive for our wealthy society (specifically Canada since I live in Wpg but much if the world is now very wealthy)? It would require serious investment but probably all investment can be re-paid back in increased economic output and reduced social programs (as the problem decreases). If I had no real monitary limit and I was paid to focus on one person or even 10 people, I alone could help uplift those few people up to being working and effective citizens. If a gov't program requires certain businesses to take on a certain # of "sponsored employees" where the employees are paid by the external source rather than the company, for one year... I help that person to prepare for the interview, get the right work wear etc. I invest in them in personal ways to hear about their troubles and help them think through decisions and actions. Housing them is even easier, Japan did that and we could surely do better. But housing is "only" a foundational thing which is way I spelled out how I would get them working.... Will everyone shut my idea down with "it will not have high success rate"? Surely society can do better than what I've thought of on my very own... So really society just doesn't care to solve these problems. I can't stand it. That homeless person could just have easily been you or me if we had been born into the same circumstances... I really want society to sooner than later become like Star Trek. Good night.

I never actually thought about the fact that there are no green stars. So there are no violet stars too, correct? Why?

Fraser, I deeply appreciate your perspective from Canada! You lack some of the biases that people from the United States have. I enjoy the reporting you do on China that most likely would be ignored in the US. Keep up the good work!

Actually the Sun's radiation peaks in the green according to the Stefan-Boltzmann law however the human brain has evolved to treat the predominate background illumination (sun-light) as neutral white. White is not a colour but this colour balancing act allows us to perceive subtle deviations from the neutral when observing objects around us. The colour balancing is perpetuated in our visual technology (displays and cameras) as set out in CCIR 601 etc. Putative aliens would presumably have colour balancing if they had eyes, based on their home star's temperature. Putting any kind of filter in front of the Sun would distort the natural light curve and be obvious to remote observers, it wouldn't have to be a "green" filter.

I was kinda surprised that you didn't mention green pea galaxies when you discussed green stars. There might be something there, but I have no idea what it might be!🤐😄