I'm pleased to see that not only was the Kugelblitz Challenge not a trick question (i.e. neither works and I was too dumb to figure out why) but that I successfully determined which one it was. I couldn't be arsed to draw a Penrose diagram about it, though, so I never did submit an answer. I just learned about Penrose diagrams rather recently from an earlier episode of Space Time and while I find them hauntingly beautiful I don't quite feel qualified to wrangle them myself.
It does give me a really pwntastic idea for a minimap for SE or my own game though - have an old-school radar circle but with a Penrose transformation applied so that it represents a vast swath of space but only highlights stuff as it gets close to your ship.

That's a cool idea.  In the literature we don't usually show the (curvy) lines of constant space and time on the Penrose diagram -- the way PBS Space Time draws it is pretty slick.  Almost looks like a gemstone.

DoctorOfSpace  I'm finding myself enjoying that channel more and more.

Given how complex the techniques for obtaining the image is, their doubt would almost be justified. :p

My brother is one of those people, a fervent believer in the Electric Universe.  Which is fine, but I currently live with him and he brings this up often

[youtube]iphcyNWFD10[/youtube]
[youtube]ViMnGgn87dg[/youtube]

 

[youtube]odiCKmM0WWE[/youtube]

My brother is one of those people, a fervent believer in the Electric Universe.  Which is fine, but I currently live with him and he brings this up often

I feel your pain.  It's a troublesome thing for the professional astronomers too.  I mean they have no idea how plasmas work.  They would have to go through a course on Electricity and Magnetism and like, no university astrophysics program offers that.

Love the video on gravitational waves.  Rana Adhikari is fantastic.

Speech recognition is also fascinating, but proof reading is advisable before publishing.

lol
Reminds me of a poorly translated instruction pamphlet I read once that said "Remember, the hardness affect protection, the thickness affect sensitivity."

...It was for a cell phone screen protector xD

[youtube]RFXHev_dLuE[/youtube]Interesting! So where there are mountains, the crust goes lower than flat areas?

[youtube]5-J6gW_w_Hs[/youtube]

So where there are mountains, the crust goes lower than flat areas?

Indeed it does. The land is heavier, after all, and while the continents assuredly do not float in the ocean, they do in fact float on the asthenosphere (liquid part of the upper mantle), so if it get thicker, it sinks in further to maintain the displacement ratio.

[youtube]-q7EvLhOK08[/youtube]

This is the best presentation on singularities I've ever seen in a popular setting.  Can't recommend highly enough!

[youtube]TbNymweHW4E[/youtube]

Math is a logical set of rules and operations (which humans create), that leads to theorems, identities, and formulas which happen to be fairly effective at describing phenomena and relationships in nature.  In other words, it is a combination of invention and discovery.  We invent the logic, and discover the consequences of that logic.  If it seems mysterious that math is "unreasonably effective" at describing nature, all it really means is that nature is logical.  What would an illogical reality be like?

It could also be argued that math is "reasonably ineffective" at describing nature.  That is, all our formulas in physics and other fields of science are just models. "Here's the essence of what I think is happening, and this is how I express that as math, and then this is what that math predicts."  The power of a model is in how well it reduces a very complicated reality into something sensible, and have success in predicting what we observe.

Like, is it weird that I can write equation

[tex]\frac{dP}{dt}=rP[/tex]

and it happens to be a good model for population growth?  Well, it shouldn't be.  All I did was say "let the population size [tex]P[/tex] change at a rate proportional to the population size."  It's a very simple model which happens to work really well for situations in which the assumption is valid (e.g. a population that exists in isolation with a lot of room and resources and no competition).  To make a better model which accurately describes a broader range of population dynamics, we would improve the logical framework.  

The equation written above is an example of a "differential equation" -- a relationship between the amount of stuff and the rates at which that stuff changes.  Most things in nature happen to be modeled as differential equations.  But the mathematics is often unreasonable here.  Some differential equations can be easily solved with pen and paper, but in general they cannot be solved analytically (as in you cannot find or write the solution with any combination of standard functions like powers or sines or roots or exponents).  Instead their solutions are approximated by algorithm -- usually on a computer -- and sometimes those solutions are also violently chaotic.  For instance... consider the three body problem.  Or the Navier-Stokes equations.

You'd think if math were built into nature, then any relationships in nature should be readily describable with math.  But... it's more complex than that.  We can describe the important aspects of the nature with logic, but that does not necessarily convert to elegant mathematical form.

We invent the logic, and discover the consequences of that logic.

True, but not necessarily in that order, which leads to the philosophical questions.  We knew how to add natural numbers before we invented the logic behind it (like the Peano axioms).  In many cases I would say that it's the discoveries that guide us to the axioms, so I think there is ground here for philosophical discussions.

PBS Space Time release a new video. It got 12 views before it was taken down
Here was the thumbnail

I hope this gets re-released because it looks like an interesting video