Synchlavier Sample
27 followers
27 followers
Synchlavier Sample's interests
Synchlavier Sample's posts
Post has attachment
Public
Post has shared content
Public
Post has shared content
Public
Application layer protocols
wikipedia.org/wiki/Category:Application_layer_protocols
wikipedia.org/wiki/Category:Application_layer_protocols
Post has shared content
Public
{UPDATED} Linux: Delete / Remove User Account Safely Including eMails and Cronjobs Safely
Post has shared content
Public
Chemical Engineering What is the Electrical Resistance of a Graphene Sheet at Room Temperature? http://ow.ly/2y0bD3
Post has shared content
Public
Understanding black holes
This is a diagram of a Schwarzschild black hole - a non-rotating, uncharged black hole that has been around forever.
Real-world black holes are different. They aren't eternal - they were formed by collapsing matter. They're also rotating. But the Schwarzschild black hole is simple: you can write down a formula for it. So this is the one to start with, when you're studying black holes.
This is a Penrose diagram. It shows time as going up, and just one dimension of space going across. The key to Penrose diagrams is that light moves along diagonal lines. In these diagrams the speed of light is 1. So it moves one inch across for each inch it moves up - that is, forwards in time.
The whole universe outside the black hole is squashed to a diamond. The singularity is the wiggly line at top. The blue curve is the trajectory of a cat falling into the black hole. Since it's moving slower than light, this curve must move more up than across. So, once it crosses the diagonal line called the horizon, it is doomed to hit the singularity.
Indeed, anyone in the region called "Black Hole" will hit the singularity. Notice: when you're in this region, the singularity is not in front of you! It's in your future. Trying to avoid it is like trying to avoid tomorrow.
But what is the diagonal line called the antihorizon? If you start in our universe, there's no way to reach the antihorizon without going faster than light. But we can imagine things crossing it from the other direction: entering from the left and coming in to our universe!
The point is that while this picture of the Schwarzschild black hole is perfectly fine, we can imagine extending it and putting it inside a larger picture. We say it's not a maximally extended solution of Einstein's equation.
The larger picture, the maximally extended solution, describes a very strange and interesting world. But that's another story, which deserves another picture.
If we stick with the diagram here, nothing can come out of the antihorizon, so it will look black. In fact, to anyone in the "Universe" region it will look like a black sphere. And that's why a Schwarzschild black hole looks like a black sphere from outside!
The weird part is that this black sphere you see, the antihorizon, is different than the sphere you can fall into, namely the horizon.
If this seem confusing, join the club. I think I finally understand it, but nobody ever told me this - at least, not in plain English - so it took me a long time.
What could be behind the antihorizon? If you want to peek, try Andrew Hamilton's page on Penrose diagrams, where I got this picture:
http://jila.colorado.edu/~ajsh/insidebh/penrose.html
I wish that Wikipedia had a really nice Penrose diagram like this! It's very important. They have some more complicated ones, but the most basic important ones are not drawn very nicely. You need to think about Penrose diagrams to understand black holes and the Big Bang!
Still, their article is worth reading:
https://en.wikipedia.org/wiki/Penrose_diagram
For more on the Schwarzschild black hole, read this:
https://en.wikipedia.org/wiki/Schwarzschild_metric
#physics
This is a diagram of a Schwarzschild black hole - a non-rotating, uncharged black hole that has been around forever.
Real-world black holes are different. They aren't eternal - they were formed by collapsing matter. They're also rotating. But the Schwarzschild black hole is simple: you can write down a formula for it. So this is the one to start with, when you're studying black holes.
This is a Penrose diagram. It shows time as going up, and just one dimension of space going across. The key to Penrose diagrams is that light moves along diagonal lines. In these diagrams the speed of light is 1. So it moves one inch across for each inch it moves up - that is, forwards in time.
The whole universe outside the black hole is squashed to a diamond. The singularity is the wiggly line at top. The blue curve is the trajectory of a cat falling into the black hole. Since it's moving slower than light, this curve must move more up than across. So, once it crosses the diagonal line called the horizon, it is doomed to hit the singularity.
Indeed, anyone in the region called "Black Hole" will hit the singularity. Notice: when you're in this region, the singularity is not in front of you! It's in your future. Trying to avoid it is like trying to avoid tomorrow.
But what is the diagonal line called the antihorizon? If you start in our universe, there's no way to reach the antihorizon without going faster than light. But we can imagine things crossing it from the other direction: entering from the left and coming in to our universe!
The point is that while this picture of the Schwarzschild black hole is perfectly fine, we can imagine extending it and putting it inside a larger picture. We say it's not a maximally extended solution of Einstein's equation.
The larger picture, the maximally extended solution, describes a very strange and interesting world. But that's another story, which deserves another picture.
If we stick with the diagram here, nothing can come out of the antihorizon, so it will look black. In fact, to anyone in the "Universe" region it will look like a black sphere. And that's why a Schwarzschild black hole looks like a black sphere from outside!
The weird part is that this black sphere you see, the antihorizon, is different than the sphere you can fall into, namely the horizon.
If this seem confusing, join the club. I think I finally understand it, but nobody ever told me this - at least, not in plain English - so it took me a long time.
What could be behind the antihorizon? If you want to peek, try Andrew Hamilton's page on Penrose diagrams, where I got this picture:
http://jila.colorado.edu/~ajsh/insidebh/penrose.html
I wish that Wikipedia had a really nice Penrose diagram like this! It's very important. They have some more complicated ones, but the most basic important ones are not drawn very nicely. You need to think about Penrose diagrams to understand black holes and the Big Bang!
Still, their article is worth reading:
https://en.wikipedia.org/wiki/Penrose_diagram
For more on the Schwarzschild black hole, read this:
https://en.wikipedia.org/wiki/Schwarzschild_metric
#physics
Post has shared content
Public
TAEVision #3D
#HEINE #Optotechnik
#Diagnosis #Optical #Instruments
#Inspection #automotive #repair
https://t.co/ruEwBILnjp
Check out @TAEVisionCEO's Tweet: https://twitter.com/TAEVisionCEO/status/778045772453511172?s=09
#HEINE #Optotechnik
#Diagnosis #Optical #Instruments
#Inspection #automotive #repair
https://t.co/ruEwBILnjp
Check out @TAEVisionCEO's Tweet: https://twitter.com/TAEVisionCEO/status/778045772453511172?s=09
Post has shared content
Public
Post has shared content
Public
Australian Scientists Created The World’s Thinnest Lens
Australian National University (ANU) Scientists have created the world’s thinnest lens, one two-thousandth the thickness of a human hair, opening the door to flexible computer displays and a revolution in miniature cameras.
#Nano #Nanotechnology #Australia #Australian #ANU
http://www.nanotechnologyaustralia.com/2016/03/13/australian-scientists-created-the-worlds-thinnest-lens/
Australian National University (ANU) Scientists have created the world’s thinnest lens, one two-thousandth the thickness of a human hair, opening the door to flexible computer displays and a revolution in miniature cameras.
#Nano #Nanotechnology #Australia #Australian #ANU
http://www.nanotechnologyaustralia.com/2016/03/13/australian-scientists-created-the-worlds-thinnest-lens/
Post has shared content
Public
LS6410 ARM11 Android Development Kit
Designed and Developed by LinkSprite the LS6410 consists of motherboard and core board. Core board.
Designed and Developed by LinkSprite the LS6410 consists of motherboard and core board. Core board.
Wait while more posts are being loaded