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The “how to build a black hole” video from PBS space time says that’s how you do it - you start with a neutron star and keep adding more mass to it, which parad

The “how to build a black hole” video from PBS space time says that’s how you do it - you start with a neutron star and keep adding more mass to it, which paradoxically makes it smaller until it becomes smaller than its swarzchild radius, becoming a black hole. Blew my mind and anyone else’s when I share the video with them! https://youtu.be/xx4562gesw0 https://youtu.be/xx4562gesw0

cletus 6y ago
That depends on what size of black hole you want to make. It works for large black holes (you need sufficient mass for the gravitational forces to be sufficient) but those black holes aren’t that useful. Smaller black holes are harder to construct but way more useful.
- willis936 6y ago
  It's simple, just deflate spacetime!
- elseweather 6y ago
  I'm curious what useful applications we have for black holes of any size
  - jakeogh 6y ago
    It's assumed that little ones are the most efficient mass to energy converters, via Hawking radiation.
  - cletus 6y ago
    There are actually a lot of theoretical applications. Black holes are likely the most efficient form of power generation that we currently know of. Black hole propulsion may well be the best form of interstellar starship propulsion. Black holes may also be the ultimate computer. If the universe continues based on it current understanding then eventually all the stars will be dead and the universe will be a dark place. The Black hole era will last trillions of time as long but may well be the golden age of civilization. Each of these topics is a rabbit hole.
  - ThrustVectoring 6y ago
    The theoretical limit of how efficiently you can turn energy into useful work depends on how cold your energy sink is. The coldest energy sink in an ever-expanding universe gets colder over time as everything spreads out and the fixed amount of energy occupies more and more space. So the hypothetical optimal end-state of an extremely old civilization is hibernating a bunch of very stable mass until the extreme far future, at which point they can drip-feed it into a black hole to do some extremely efficient computation.
firebaze 6y ago
Really don't want to be dismissive, but this guy appears to me as having one gesture (both hands towards the viewer, to underscore the graveness of his words), a good haircut and that's about it. If find it hard to take a presentation like this serious. Most of the mentioned facts are right as far as i can judge it without having a major in physics, but to me this is so very much worse than a link to backreaction (Sabine Hossenfelder), startswithabang (Ethan Siegel) or almost any other serious physics blog out there as anything else. I suppose this will get downvoted, and I'm fine with that, but please explain to me why a self-promoting video guy with probably 5% understanding of the matter compared to a serious pop-sci blog is so relevant to you. Heck, even wikipedia has more information than this clip. And it doesn't cost 13 minutes + ads, just 5 minutes to read. It's not a paradox a neutron star gets smaller the more mass you add to it. This is also true for Jupiter-sized objects; it is a function of density, matter and gravity, and not related (in this case) to special relativity.
- nynx 6y ago
  Matt O'Dowd is a well-known physicist. I'm not sure why you feel that you can judge him so quickly.
- ramraj07 6y ago
  I have no idea what you’re talking about? It’s a pbs YouTube channel, the host is a professor in astrophysics and has generally made sure he doesn’t oversimplify anything. I like Sabine’s videos sometimes when she’s not bonkers kookoo but this guys not trying to be controversial.
- gizmo686 6y ago
  That self-promoting video guy is an astrophysicist, with a significant amount of papers published about black holes. You are free to not like his mass-market material, but from a technical level, he is quite qualified to talk about the subject. https://en.wikipedia.org/wiki/Matt_O%27Dowd_(astrophysicist) https://en.wikipedia.org/wiki/Matt_O%27Dowd_(astrophysicist) https://www.mattodowd.space/ https://www.mattodowd.space/ https://ui.adsabs.harvard.edu/search/p_=0&q=author%3A%22O'Dowd%2C%20M.%20J.%22&sort=date%20desc%2C%20bibcode%20desc https://ui.adsabs.harvard.edu/search/p_=0&q=author%3A%22O'Do...
hinkley 6y ago
I've seen a couple astrophysics videos over the last few years that put forward the theory that many black holes are the result of a neutron star forming in a binary or trinary star system. The initial explosion and the ejecta creating a situation where the neutron star begins to siphon material off of its partner.

cletus 6y ago

That depends on what size of black hole you want to make. It works for large black holes (you need sufficient mass for the gravitational forces to be sufficient) but those black holes aren’t that useful. Smaller black holes are harder to construct but way more useful.

willis936 6y ago
It's simple, just deflate spacetime!
elseweather 6y ago
I'm curious what useful applications we have for black holes of any size
- jakeogh 6y ago
  It's assumed that little ones are the most efficient mass to energy converters, via Hawking radiation.
- cletus 6y ago
  There are actually a lot of theoretical applications. Black holes are likely the most efficient form of power generation that we currently know of. Black hole propulsion may well be the best form of interstellar starship propulsion. Black holes may also be the ultimate computer. If the universe continues based on it current understanding then eventually all the stars will be dead and the universe will be a dark place. The Black hole era will last trillions of time as long but may well be the golden age of civilization. Each of these topics is a rabbit hole.
- ThrustVectoring 6y ago
  The theoretical limit of how efficiently you can turn energy into useful work depends on how cold your energy sink is. The coldest energy sink in an ever-expanding universe gets colder over time as everything spreads out and the fixed amount of energy occupies more and more space. So the hypothetical optimal end-state of an extremely old civilization is hibernating a bunch of very stable mass until the extreme far future, at which point they can drip-feed it into a black hole to do some extremely efficient computation.

firebaze 6y ago

Really don't want to be dismissive, but this guy appears to me as having one gesture (both hands towards the viewer, to underscore the graveness of his words), a good haircut and that's about it. If find it hard to take a presentation like this serious. Most of the mentioned facts are right as far as i can judge it without having a major in physics, but to me this is so very much worse than a link to backreaction (Sabine Hossenfelder), startswithabang (Ethan Siegel) or almost any other serious physics blog out there as anything else. I suppose this will get downvoted, and I'm fine with that, but please explain to me why a self-promoting video guy with probably 5% understanding of the matter compared to a serious pop-sci blog is so relevant to you. Heck, even wikipedia has more information than this clip. And it doesn't cost 13 minutes + ads, just 5 minutes to read. It's not a paradox a neutron star gets smaller the more mass you add to it. This is also true for Jupiter-sized objects; it is a function of density, matter and gravity, and not related (in this case) to special relativity.

nynx 6y ago
Matt O'Dowd is a well-known physicist. I'm not sure why you feel that you can judge him so quickly.
ramraj07 6y ago
I have no idea what you’re talking about? It’s a pbs YouTube channel, the host is a professor in astrophysics and has generally made sure he doesn’t oversimplify anything. I like Sabine’s videos sometimes when she’s not bonkers kookoo but this guys not trying to be controversial.
gizmo686 6y ago
That self-promoting video guy is an astrophysicist, with a significant amount of papers published about black holes. You are free to not like his mass-market material, but from a technical level, he is quite qualified to talk about the subject. https://en.wikipedia.org/wiki/Matt_O%27Dowd_(astrophysicist) https://en.wikipedia.org/wiki/Matt_O%27Dowd_(astrophysicist) https://www.mattodowd.space/ https://www.mattodowd.space/ https://ui.adsabs.harvard.edu/search/p_=0&q=author%3A%22O'Dowd%2C%20M.%20J.%22&sort=date%20desc%2C%20bibcode%20desc https://ui.adsabs.harvard.edu/search/p_=0&q=author%3A%22O'Do...

hinkley 6y ago

I've seen a couple astrophysics videos over the last few years that put forward the theory that many black holes are the result of a neutron star forming in a binary or trinary star system. The initial explosion and the ejecta creating a situation where the neutron star begins to siphon material off of its partner.