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Science and Astronomy Videos

Posted: 14 Dec 2016 16:57
by Hornblower
Feel free to move this thread around to a more fitting spot as it develops, but I think this is the proper place for now.
Post interesting science/math/astronomy videos here!

Science and Astronomy Videos

Posted: 14 Dec 2016 20:50
by Watsisname
Neat!  On the old forum I also talked about the idea of surrounding a region of space with a sufficiently massive shell such that it forms a black hole and dooms the interior, even as the interior doesn't notice anything weird whatsoever until it gets swept up in a singularity.  The challenge question posed about trying to escape this scenario is interesting!

Added:  And yes, one of the two plans will definitely NOT work, while the other potentially could work, and by common intuition that is not necessarily obvious.  But the fun part, which I won't spoil, is showing why one plan is better, using the Penrose diagram.  If you understand how the Penrose diagram works from his presentation, then this is actually not too hard to demonstrate, and the physical interpretation of it is very cool.  If anyone is trying this challenge and is stuck or confused about some aspect of it, feel free to ask questions. :)

Science and Astronomy Videos

Posted: 21 Dec 2016 17:49
by Hornblower

Science and Astronomy Videos

Posted: 22 Dec 2016 04:55
by Watsisname
Oh snap, he quoted me in the Q&A. :)

Science and Astronomy Videos

Posted: 22 Dec 2016 09:54
by Hornblower
Watsisname wrote:
Oh snap, he quoted me in the Q&A. :)

I thought he said watsisname too  :)
Unless you really said that, I think he said "whatshisname"

Science and Astronomy Videos

Posted: 22 Dec 2016 10:50
by Hornblower

Science and Astronomy Videos

Posted: 22 Dec 2016 13:16
by DoctorOfSpace
Like I have said for years, overpopulation is nonsense. The real problem is resource distribution.

Science and Astronomy Videos

Posted: 23 Dec 2016 17:33
by Hornblower

Science and Astronomy Videos

Posted: 28 Dec 2016 08:27
by Salvo
DoctorOfSpace wrote:
The real problem is resource distribution.

And the fact that the average age is increasing... but it's related to resource distribution. And I guess this thing only affects the pure-economical part of the problem.

Science and Astronomy Videos

Posted: 28 Dec 2016 12:35
by DoctorOfSpace

Science and Astronomy Videos

Posted: 30 Dec 2016 23:57
by DoctorOfSpace

Science and Astronomy Videos

Posted: 04 Jan 2017 15:50
by Hornblower


Also, Happy 12017

Science and Astronomy Videos

Posted: 04 Jan 2017 18:53
by Watsisname
Happy to see 12017 catching on, and hopefully the year we get our first direct image of a black hole event horizon. :)

Challenge answer is really cool.  It's so weird to think that the 'Disco Ball' does indeed reflect the light outward, but that outward is still towards the singularity, sweeping up the Earth with it.  Perhaps the most intuitive explanation is with the 'flow of space' analogy for space-time curvature.  Once the shell of light has come within its own Schwarzschild radius, it is causing the space immediately behind it to flow inwards greater than the speed of light.  It's as if the light is digging a hole for itself, and the hole is so steep that it can't climb back out.  So even if you can perfectly reflect the light, you can't reflect this inward rush of curved space-time.  It sweeps up everything inside the event horizon, including the reflected light pulse, and consumes the Earth in singularity.  

...which, I think, is the coolest description of this Kugelblitz weapon ever.  The target is destroyed by space itself!

Science and Astronomy Videos

Posted: 05 Jan 2017 02:07
by DoctorOfSpace
Watsisname wrote:
Source of the post hopefully the year we get our first direct image of a black hole event horizon.

I look forward to the conspiracy theorists claiming it doesn't count.



Science and Astronomy Videos

Posted: 05 Jan 2017 17:05
by Watsisname
DoctorOfSpace wrote:
I look forward to the conspiracy theorists claiming it doesn't count.

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