Open thread, May 22 - May 28, 2017

Arimaa was designed for this purpose and computers are now better at it.

How about Dixit?

An interesting question.

My first thought was Nomic, but I don't know how viable is it with two players only. Hmm...

This came up in our last meeting, as you might imagine. We already had a 10 minute rate limit implemented for posts and links.

Perhaps check out Piping Rock? They ship worldwide and their prices seem pretty good. I've gotten l-theanine from there before.

Melatonin is widely available in Europe. If you are willing to use websites in other languages there are many options. For example, Netherlands. I have seen French and Italian sites, but I didn't save them. It was recently legalized in Germany.

Can you buy it in liquid form? Then you can dilute it to whatever dose you want.

Given perfect conduction (uniform surface temperature, bright side and dark side have the same temperature at all times), https://en.wikipedia.org/wiki/Black-body_radiation#Temperature_relation_between_a_planet_and_its_star applies : temperature does not depend on rotation speed. Then T = T_sun sqrt(R_sun/(2D)) ; it is the temperature T that balance incoming radiation P_inc = pi (R_planet^2) (R_sun^2) (T_sun^4)/(D^2) and emitted radiation P_em = 4 pi (R_planet^2) * T^4

Let's suppose no conduction at all. The bright side and the dark side does not exchange heat at all. Let's take two limiting cases : tide-locked planet, and an "infinitely fast" fliping planet.

In the first case, the dark side of the planet is at absolute 0. The bright side of the planet receives the same incoming radiation but emit half its radiation (halved surface) -- change 4 pi to 2 pi in P_em. Its temperature is T_bright = 2^(1/4) T. Average temperature of the planet is (0+T_bright)/2=2^(-3/4) T

In the second case, each side gets half the incoming power from the sun and radiates half the energy (surface halved). Average surface temperature of the planet is the same that the average surface temperature of any side, which is the same temperature that the perfectly conducting planet, T (the .5 from halved incoming power and .5 from halved outgoing radiation cancel each other).

So : rotation raises temperature of a non-perfectly-heat-conducing planet, bringing its surface temperature closer to the perfectly-heat-conducting planet surface temperature.

So consider an extreme: a tide-locked planet in that same orbit. if it begins to rotate, does the average temperature increase or decrease? I don't actually know, and can't think of a reason it would change. The sunrise will now have access to surface area not yet at the inferno equilibrium, so it'll be absorbing heat. But the sunset is doing the opposite: radiating all that heat that's no longer being replenished.

Does it matter if the planetary material absorbs and radiates heat at different rates? Is that even possible?

Edit: extend this idea. Take a tide-locked planet at equilibrium. Magically flip it so the cold side is toward the sun and the hot side toward space. Give it time to come back to equilibrium. Average surface temperature at t and t is the same, right? During this period, does the average rise and then fall back, or does it drop and then rise back?

I think I recall that hot things radiate faster than cold thing absorb heat, which implies it'll overall cool and then come back up after the now-cold side reaches minimum temperature before the now-hot side reaches maximum. which implies that spinning faster makes the average cooler.

I guess there may be some energy effects of the rotation itself, generating a bit of heat from internal differentials.

I don't know the answer but let me write down some thoughts.

If I'm a point on the surface of a planet then I spend the day slowly getting warmer as I absorb sunlight and the night slowly getting cooler as I radiate my heat into space. If the days are longer then the temperature I reach during the day is higher, which means that when the night begins I radiate heat more rapidly into space. But conversely by the end of the night I've cooled down to a lower temperature so I absorb more heat from the sun at the star of the day.

In fact none of this should matter. Can't we say that the space at that distance from the sun has a particular temperature, and both planets are in thermal equilibrium with that space, so they have the same temperature? That's not such a convincing argument, since the space near a star is not a typical thermodynamic system.

What about atmospheres? They should help warm up the (solid) surface of the planet via the greenhouse effect. I guess the faster spinning planet has a thinner atmosphere, because of centrifugal force, so maybe it's colder.

1) Prediction is not intelligence. Intelligence is goal-driven action, which makes use of conditional prediction (if I do X, Y is more likely).

2) stocks are a game where the vast majority of us are at an information disadvantage. It only takes a very weak efficient market to make it unbeatable by the layperson.

3) stock picks are useless for reason #2.

4) calling something low-status is low-status around here. You're better off decomposing the reasons something might affect peer perceptions of the poster.

My interpretation of the general sentiment is that market prediction, for it to be remarkably fruitful, has long escaped the possibility for a single individual who is not already blessed by a crapload of money.

Prediction is not intelligence. Good predictions are one of the signs of intelligence.

Why is there not more discussion about stock picks here?

Apply intelligence :-) If you want to extract money out of financial markets, is picking stocks the right place to be?

Even if you don't believe in the efficient market, picking publically traded stocks yourself means that you believe you can win in zero-sum games against professional investors who are supported by huge computer models and research analysts.

If you have inside information about a company that's not known to the professional investors you might make good trades but you are also violating the law and it would be stupid to publically talk about your trades and their justification on a forum like this.

Another way to make money is to bet on effects that are illiquid enough that professional investors aren't interested. If you have found a trade from which $10,000 can be extracted you are also not benefiting from being public about your predictions. A friend for example used to do arbitrage between different bitcoin markets. While that happened to be profitable, it was stupid to talk about it in a public venue like this.

You probably mean Eliza and the story of Weizenbaum's secretary.

Differences with MIRI?

This is a good example of the type of comment I would like to be able to downvote. Utterly braindead political clickbait.