The level of math amenable to apps isn't really what Su is talking about.
I would suggest learning proofs, and maybe pick up some Art of Problem Solving books. Or perhaps working through the foundational curriculum of any decent math program (e.g., algebra, analysis, topology, number theory, etc.).
Khan Academy can get you pretty far, if you like going through the remedial stuff then you can even take the quizzes to get "Mastery" in various subjects like Algebra, Trig, I think Calculus too. But I'd love something else that is more adaptive and gives you exercises and education as you go. As a hobbyist one of the hardest part is figuring out where to jump in so you're neither bored nor overwhelmed.
We _are_ making progress in space exploration but the moon isn't of much interest anymore. The technology that is being developed to reach Mars for example is "technology we don't currently posses."
The moon has no resources to enable living there. You will always have to bring in air, water and food. Also, no current idea for something profitable to do there (Helium-3 mining is very theoretical). Some people want a moon base before a mars base, but I think they're mostly thinking about how much closer it is, not about what they want it for.
There's actually plenty of oxygen on the Moon, trapped in various rocks.
Water and food are indeed trickier; the Moon does have some trace amounts of carbon (deposited by solar wind) and hydrogen (at the poles), but extracting enough of those elements to sustainably support living there is unlikely unless we make some major discoveries or figure out a more reasonable way to import such things (one idea is to capture hydrocarbon-rich asteroids and park them in lunar orbit, but that ain't exactly my idea of "reasonable").
As for profitability, the Moon happens to be rich in silicon; a far-fetched idea might be to build a whole bunch of lunar microchip factories. The Moon is also full of raw materials in general, and getting them into space (e.g. to build spacecraft or to import to Earth) is a lot easier than getting such material into space from Earth. This makes the Moon a potentially-valuable staging point for missions to Mars and elsewhere.
If there is indeed water (or some other hydrogen source) on the Moon in sufficiently-abundant quantities, lunar fuel depots would actually be feasible; there's been quite a bit of work in recent decades around using silanes (hydrosilicons) as a useful fuel, replacing the need for hydrocarbon-based fuels (or using hydrogen directly).
The Moon could certainly be lived on easily, but with a mere 1-second communications lag between Earth and Moon, using remotely-operated drones to completely build a self-sustaining habitation before sending even a single human there would make more sense.
Indeed it would. I recall some work being done on a giant 3D printer than that print buildings out of concrete; figuring out a way to do the same with lunar materials would be a huge step in the right direction.
Complete nonsense. The moon has water which can obviously be broken down into oxygen and rocket fuel. The idea that we know the extent of the moon's resources is naive.
You're correct in that large, (comparatively) easily mined water ice deposits are located in permanent shadow at the poles, but there is likely water available in most locations, if you dig down below the surface.
>Are you saying you where talking metaphorically? Because the metaphor compares two similar things.
A metaphor compares two things similar from a certain aspect -- they could still differ in every other way. One could use a metaphor from agriculture to clarify their point on a political issue, for example.
>Also, why is a metaphor needed here?
For the same reasons that it's needed elsewhere. To get the point across in a simplified way, because people can understand a phenomenon better in one domain than they can in another (aka "domain dependence").
> A metaphor compares two things similar from a certain aspect
When I said "the metaphor compares two similar thing" I didn't mean metaphors in general, I meant your metaphor specifically compares two things that are similar. The relevant differences between NY and the moon do not exist between NY and Illinois.
> For the same reasons that it's needed elsewhere
Metaphors are often of dubious value. They can be used to clarify unfamiliar situation, where the bounds of the metaphor are clear; or, perhaps as in this case, encourage similar thinking about two related concepts.
But you provided a metaphor here without providing clarity on what the point was. When I think "why would I build a city in Illinois, when there already one in NY", none of the answers I come up with apply equally to the moon. e.g. land is cheaper/convenient (not on the moon), the scenery is better (maybe true, but not to outweight other more pressing concerns) etc.
I'm going to disagree here, because this idea took me a long time to develop and has been very helpful.
I spent a long time trying to make myself happier, and I just grew more miserable. I started to work instead on practical goals (I.e fixing the problems i had caused for myself) and found myself to be happier.
Now I think happiness is a natural result of accomplishment things that help you as a person. Pursing happiness directly seems like a category error. It's not a valid goal. The best metaphor I could give you is that "pursuing happiness" is akin to getting in the car and asking your gps "take me to the destination."
It will take you wherever you went last time. Occasionally that may overlap with what's actually good for you, but usually it's wherever you went last time.
"The destination" isn't a meaningful destination. "A gas station", or "a restaurant is."
Now, whenever you start driving, it's true that you are always "headed to the destination" but this is only true in the vacuuous sense of a tautology.
The happiness which results from accomplishing our goals, I now think is a return to a natural baseline state. It's when you don't need anything that you feel happy to just be as you are. Getting to a destination feels good not because "you have arrived", but because you popped the last frame off the goal-seeking stack.
What are the motivations behind what you're doing? Because likely, at the very least it stems from a Pavlovian habit originally triggered by happiness.
"There is nothing in goodness above pleasure, there is nothing in evil below pain" - Sefer Yetzirah (Hebrew book of creation)
When it comes down to it happiness is the point of life.
It's true with the normal definition of happiness. Think about it. Whatever you're doing now is an attempt to get you to a happy state. If you're already happy, it'll fade and you will take more actions to be happy again. This seems to be part of our human condition.
And it's an 'additive' kind, being that I get an additional boost of happy neurotransmitter thinking I'm adding a beneficial comment, thus potentially helping a reader to an understanding I have & perceive that they might not have as strong a grasp of. I like to help, thus am happier. If the form button fails to submit my contribution, I feel disappointment. At having wasted the effort in trying to contribute, but moreso, at not contributing.
I thought the Ancient Aliens series was interesting. A group of friends showed it to me and some believed in it. However, we started following the logic they use and it basically boils down to this:
We don't know how this was done so therefore Aliens did it.
So the most honest thing they can actually say is they don't know.
