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  • black holes only seem to come in two radically  different sizes they're either around five to a  

  • hundred times the mass of our sun what are called  stellar mass black holes or they're millions to  

  • billions of times more massive than our sun aptly  named supermassive black holes so what is going on  

  • here where are all the in-between sized black  holes and why does the scale range stop there  

  • could black holes be really tiny or even as new  research suggests stupendously large you may  

  • remember when the large hadron collider was first  coming online some alarmists claimed it would  

  • create a black hole that would destroy the earth  while microscopic black holes seem far-fetched  

  • there are some theoretical ways they could  exist but you'd need extra dimensions to do it  

  • gravity as we know it isn't strong enough  to compress subatomic particles small enough  

  • to make them collapse into a black hole because  that size is smaller than the smallest meaningful  

  • measurement of distance the plank length if  discovered microscopic black holes would change  

  • our understanding of how gravity works at the  quantum scale and even imply the existence of  

  • extra dimensions that amplify gravity's force so  microscopic black holes could be made in particle  

  • accelerators but they would also exist for only  the briefest of moments decaying in an octillionth  

  • of a nanosecond not exactly enough time to devour  the entire planet so if they do exist they're  

  • nothing to lose sleep over stellar mass black  holes though are very much real and we have a  

  • pretty solid understanding of how they form when  large stars run out of fuel they collapse and go  

  • supernova if the core they leave behind is more  than about three solar masses the star's remnants  

  • collapse in on themselves and a black hole is born  these black holes can grow by devouring nearby  

  • material or merging with neutron stars or other  black holes you might imagine if a stellar mass  

  • black hole was allowed to just keep accumulating  matter eventually it would balloon to the size  

  • of the supermassive black holes that we think  are at the center of almost all large galaxies  

  • but there's an upper limit to how fast matter can  fall into a black hole so growing that large would  

  • take billions of years since we've observed black  holes with billions of solar masses that formed  

  • within hundreds of millions of years of the big  bang something else must be at work the mechanism  

  • for how supermassive black holes come to be is one  of the great mysteries of astronomy there are a  

  • few competing ideas each with their own strengths  and weaknesses for example maybe they formed from  

  • large seed black holes that are already very  massive when they form and then they continue  

  • to grow as they suck in matter these large seeds  would be the remnants of stars as big as 250  

  • 000 solar masses stars that large should be rare  making large seeds less likely another idea is  

  • they're the product of several intermediate-sized  black holes these intermediate-sized black holes  

  • could form in dense star clusters as stars  collide after formation they sink toward the  

  • center of a galaxy where they merge as i said  before though there seems to be a gap in the  

  • sizes of black holes there is very little evidence  that intermediate-sized black holes exist beyond  

  • supermassive black holes there could be even  more jumbo cosmic pits one recent suggestion is  

  • there could be black holes larger than a trillion  solar masses more than 10 times larger than even  

  • the very biggest black hole we've discovered  the researchers who proposed their existence  

  • dubbed them stupendously large black holes even  our explanations for supermassive black holes  

  • wouldn't account for these giants their existence  would require us to rethink how black holes form  

  • or maybe there just is an upper limit to how  big black holes can get black holes could  

  • run the gamut from the microscopic to the mind  meltingly massive but so far the only thing we  

  • know for sure is they exist in two size ranges  and we're not even certain how the larger size  

  • is possible there's no doubt scientists are going  to keep probing for black holes at all scales  

  • because black holes have not only captured light  but our imaginations too you might think that  

  • stupendously large black holes are the result  of when supermassive black holes combine but  

  • something called the final parsec problem makes  their merger impossible check out my video on that  

  • here all right wild hypothesis time where do you  think all the intermediate-sized black holes are  

  • let us know your thoughts in the comments be sure  to subscribe and i'll see you next time on seeker

black holes only seem to come in two radically  different sizes they're either around five to a  

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B1 black supermassive black supermassive black hole large hole

How Big Can a Black Hole Get?

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    林宜悉 posted on 2020/10/26
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