MigL

If looking at it in terms of economics, of course it is cheaper to just stop doing what is causing the increase in CO2 levels. What about when you take into account the economic losses from such an approach ? That's the beauty of trees; it doesn't matter where you plant them. If you use the geothermal energy generated in Iceland to provide irrigation to arid African savannah, you could grow a forest that captures CO2 from the whole atmosphere. The trees don't need to be in Iceland.

I was just about to explain how calculus arose out of the limiting value for a function when the change approaches zero when you posted your excellent response; including the product rule, no less.

OK no PM; how about the boxing gloves approach? Might beat some sense into both of them 😄 .

The question does not make sense. Is the asteroid frozen water/methane, or a pebbly rock, or metallic ? All would require different methods. As the question stands, my solution ( also non-sensical ) is to move the Earth out of the way.

I think you are ignoring part of the 'problem', or the source. The burning of fossil fuels is not the problem, as it was done since the 'invention' of fire, with no adverse consequences ( other than cigarette smoking 😄 ). Even forest fires, while releasing carbon into the atmosphere, make way for new arboreal growth that recaptures that carbon, and maintains equilibrium. It was only during the last couple of hundred years ( industrialization ) that the rate of man-made release of atmospheric CO2, surpassed nature's ability to re-capture and sequester that carbon into living organisms, creating increasing CO2 atmospheric levels, and a shifting equilibrium. The problem is then twofold; the rate of release has increased, and the rate of re-capture hasn't kept pace. The solutions ( simplistically ) are, reduce the former, or increase the latter.

Oh my ... I do believe we have a childish feud going, which now threatens to derail a second thread. Please take it to PM, or one of you travels to the other's location and you both put on boxing gloves, and step in a ring.

I've only ever attended Brock University ( southern Ontario ), which, at the time was about 10 years old, and its sciences departments were run in the old Corning Glass Lab separate from the main small campus. One of my nephew's best friends, graduated from there and went on to do a PhD in Physics, at the Max Planck Institute in Germany. The daughter of my ophthalmologist also graduated from Brock, and went on to complete her studies at Princeton to also become an ophthalmologist, specializing in glaucoma, but unfortunately ( for me ) in Philadelphia. Those two schools of higher education have probably turned out more Nobel laureates than the next 10 combined, and would have been my first choices for Physics. So the US has 50 % of the ( what I consider ) best universities.

The Earth is a closed system. All the carbon was already here before atmospheric CO2 levels started to rise. I didn't come from anywhere else, and it won't be going anywhere else. Any reduction will come from 'locking it' in other forms, such as in solution or rocky compounds, or even plant and animal life that in a few million years become fossil fuels. The problem we currently have is that the rate of release of carbon into the atmosphere is much greater than the natural processes that re-capture it; adding to, or speeding up, those processes, can help just as much as reducing the rate of release.

I firmly believe people should stick closely to what they do best, and not venture too far outside their area of expertise. I am sick and tired of actors, musicians and other entertainers pushing their opinions on social/political/climate/etc. matters, that they have no clue about, but whose opinion carries a lot of weight simply because they have a large audience for their views. I'm also tired of failed entertainers, whose only claim to fame as an entertainer is as a caricature of themselves ( with orange hair, no less ), running for public office ( or the Presidency even ), and half of the population of the most advanced country in the world actually thinking he'd be good at it. I wonder what N Degrasse-Tyson would say about that ? He is a scientist, excellent science communicator, and his comments about mass shootings are scientifically accurate facts, albeit, not very sensitive. Then again, he's not a sociologist, so why expect a socially sensitive comment from him ? He's had other problems ( with women ) in past years also. Why does America expect people with even the slightest bit of 'fame' to have an answer for any problem or be great human beings ? N D-T is good at what he does; other aspects of his life, or opinions, are just as valid/invalid as Joe Blow's at the local bar.

Oh, you expected me to read the book before replying ? ( just kidding; I know what you mean )

Atomic weapons are different. You don't need to control the know-how, if you can control access to the fissile material. Have you tried getting some Plutonium or enriched Uranium ? That's when the black choppers will land on your front lawn, and you'll disappear.

There are two factors associated with risk analysis. One involves the severity of the occurrence, the other is the probability of occurrence. Consider a city. There are numerous sidewalks with litter on them, and only one sidewalk with a 20 ft deep hole. The probability of tripping on litter is very high because there is so much of it, but the severity is very low, maybe a twisted ankle or scrapped knee. The probability of falling in the hole is very low, as there is only one, but the severity is extremely high, resulting in death. I think Dimreepr and MSC are each focusing on only one aspect of risk analysis. Dim is focused on the improbability of a nuclear exchange, with respect to the much higher probabilities of other death producing incidents; after all, none have happened for 70 years. MSC is concerned about the severity of a nuclear exchange, that could destroy our way of life, and disregarding the probability of it occurring. Think you guys can cut each other some slack 🙂 ?

Absolutely. Since technology, transportation and agriculture are such large sources of greenhouse gas emissions in developed countries, let's scale it down, and stop sending food aid to those countries that don't emit nearly as much GHGs, but can't feed themselves. Oh ... wait. That's not what you had in mind ? I don't mean this as a criticism of your post; we certainly have excesses. It's not a simple problem, and it certainly doesn't lend itself to simple solutions

A lot of this stuff was declassified a little over ten years ago. The Area 51 File: Secret Aircraft and Soviet MiGs | National Security Archive (gwu.edu) What would you have told him in the intervening 30 years ? Probably that it was a weather balloon or atmospheric anomaly. I don't think they ever claimed these unidentified events were of alien origin. ( maybe Earthly alien, as in foreign, such as Chinese 'weather/spy' balloons )

Both are hypothetical, as is much of the other stuff mentioned. I can, however, show you pictures of a Black Hole. ( or you can google it )

As I was the one who made( what I thought was ) lighthearted comment about rednecks and anal probing, I feel I should respond, Would an alien civilization that possesses technology to travel the stars, and that doesn't want to be detected, not have some sort of visual stealth technology, or at least, radar stealth technology, like we already have ? Maybe we should then stick to more probable terrestrial phenomena. And I know you're feeling a little 'ganged-up' on, and maybe getting a little irritated,but I think you missed the point of Dimreepr's post. There are similarly many unexplained phenomena which some people attribute to ghosts. that these phenomena actually involve ghosts is equally unlikely. Or are you suggesting we should also investigate ghosts, as they remain unexplained ? With respect to US military ( DARPA ) secrets, in the 1980s the military began investigating stealth technology that eventually resulted in the L-M F-117/F-22/F-35, and the N-G B-2/YF-23/B21. These involved demonstrator projects, and since stealth tech was in its infancy, it involved crude, almost non-flyable shapes that were optimized for as much stealth as they could get. The L-M Have Blue demonstrator had a diamond shaped planform, with all angles optimizwd for least reflection, and would have been unflyable if not for computer-controlled fly-by-wire. The N-G Tacit Blue demonstrator had an inverted bathtub shape to the fuselage, but normal wings/control surfaces, as N-G was interested in the flying wing/blended body approach to their B-2 design. Both are now declassified, and you can google pics of both. I wonder how either of those would have looked to a crop-duster pilot who happened to spot one ? And would the military have admitted what it was ? Th

That only applies to drunk young men and desperate and dateless older ones who frequent those types of establishments, John. And yes, I've fit both descriptions a few times and many years ago 😄 .

I'm sure he'd be a lot more agreeable as to the value and purpose of Philosophy if he had the opportunity to chat with our own Eise.

No doubt. But in order to become an advanced civilization, they undoubtedly would have learned to prioritize their needs above their wants. Cost is not only a monetary issue; for all we know aliens don't use currency. But there are 'costs' in terms of resources, energy, and time that are not so easily discounted.

Not just one. There are many possibilities much more likely than getting hit by a meteor ( Ha Ha😄 ) Seriously. Propose as many as you like. Or the one you think will work best, or fits best with the data from UAP sightings. We can go through the benefits/problems involved with any method you propose, and hopefully we'll all learn something in the process.

Siince you involved me also, I had to read it too. The conclusion I came too is that lack of viable data does not give me reason to attribute an event to highly unlikely causes. I don't need a meteor to hit me on the head to reveal their existence, but if a rock hit me on the head, I would first look at the window above my head, or if INow is lurking nearby and throwing rocks at me. Those are way higher on the list of possible causes. Very well. Propose your method, because so far we have self-replicating probes, Alcubierre drive ships, solar sails, millions of VN nanoprobes, etc. All have problems. Suggest your method of choice, and we'll see if it is viable. Also include an effort/benefit analysis, as no one ( not even aliens ) would send a probe that returns nothing. We don't even go to the Moon anymore because of effort/cost; I'm sure an undertaking requiring effort/cost many orders of magnitude more has to provide some return. ( no one is going to send a probe into a Black Hole )

One problem I have with the central singularity. What happens when you apply Heisenberg's Uncertainty Principle to the singular event ( whether spatial or temporal singularity )? An exact location would mean indeterminate, even infinite, momentum, while an exact time would mean indeterminate, even infinite, energy. How would a particle, localized in such a way, remain trapped within the Event Horizon ? Now make that argument for all particles ingested by the BH and you have a BH which cannot exist. IOW, the singularity renders the theory inconsistent; either a singularity cannot exist, or Black Holes cannot exist. Yet we have photographic evidence of Black Holes, so where does that leave us ? I would be interested in a link to this article also. I'm interested in the proposed method ( pressure or force ) used to resist gravitational collapse at this radius.

I like indulging nice guys, Moon, so I'll start us off. Consider a constant acceleration ship, say 1g, for the confort of the occupants. "From the planetary frame of reference, the ship's speed will appear to be limited by the speed of light — it can approach the speed of light, but never reach it. If a ship is using 1 g constant acceleration, it will appear to get near the speed of light in about a year, and have traveled about half a light year in distance. For the middle of the journey the ship's speed will be roughly the speed of light, and it will slow down again to zero over a year at the end of the journey. As a rule of thumb, for a constant acceleration at 1 g (Earth gravity), the journey time, as measured on Earth, will be the distance in light years to the destination, plus 1 year. This rule of thumb will give answers that are slightly shorter than the exact calculated answer, but reasonably accurate." From Space travel under constant acceleration - Wikipedia We can then make other quick estimates to travel time "From the frame of reference of those on the ship the acceleration will not change as the journey goes on. Instead the planetary reference frame will look more and more relativistic. This means that for voyagers on the ship the journey will appear to be much shorter than what planetary observers see. At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years ship time, and about 113,000 years planetary time. If the last half of the trip involves deceleration at 1 g, the trip would take about 24 years. If the trip is merely to the nearest star, with deceleration the last half of the way, it would take 3.6 years." Now you might say"That's not too bad.". Only 113 000years pass on their home world to send a ship 100 000 light years. And a relatively short time to send it to a nearby star. Even doubling that time for two-way journey seems reasonable. Now comes the hard part. ( and I'm not going to attempt to quickly find/perform the calculation; I'll leave it to better, more fastidious, minds than mine ) How much Hydrogen do you need to carry, or collect along the way, in order to sustain a fusion reaction capable of sustaining a constant 1g acceleration/deceleration ?

Correct. We know of no force which can resist gravity once Neutron degeneray is exceeded in a neutron star, This is according to GR and QFT. Both of which have specific areas of applicability. When outside those areas they 'fai' by throwing up infinities; like at the center/future of a BH. IOW, points of infinite density are non-sensical predictions of badly applied models/theories. Also keep in mind that the central singularity, while being the event where geodesics end ( akin to latitude/longitude at the Earth's poles ), is not a location in space, but an event in time, and an infalling observer would be 'running into other stuff' at the end of time, not at the center. X-posted with others

You're taking that a bit too far. Aliens who are just like us, would require those things, but life, any kind of life, has some basic universal needs. It would need an energy/food source and to reproduce; that is all. Further, any life that emerged through an evolutionary process, would tend to optimize conditions to satisfy those needs. Their motivations, and decision making, would be based accordingly, and I don't expect that to change, even for a civilization that has been around for billions of years. But you are right. There is a slim possibility it could be ET aliens. Or time travelers, ghosts, fairies and leprechauns. But when that trivial possibility is many orders of magnitude less likely than a 'hubcap thrown in the air', it's probably OK to discount it. As to the technological obstacles to alien visitation, the Fermi Paradox/Drake Equation would have us inundated with alien civilizations, most of which should be much older than our relatively young one. Yet none have made definitive contact. You would think at least one would have, even if others are just playing hide-and-seek with us. Do you think maybe that means technological obstacles to interstellar travel are not easily dismissed ? Or maybe they're too busy with concerns about energy/food sources and reproduction, to send Von Neumann probes to other star systems to gather information which they may never recover.