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One atom black hole

  1. Apr 4, 2010 #1
    good morning everybody

    i had a question that i found no answer for it on the internet

    can one atom become a black hole ??

    if no, what is the condition that prevent it ??

    hope you help me answering this question

    best regards
     
  2. jcsd
  3. Apr 4, 2010 #2
    Its possible, but Stephen Hawkings radiation (if he's right) prevents your one atom black hole from sustaining for enough time to swallow any thing near it. In fact the black hole radiates SH radiation very rapidly and disappears(safely). Hope I answered your question.
     
  4. Apr 4, 2010 #3
    thank you a lot for your reply

    in fact, yes this answers my question but i would like to ask further more questions

    1- what is the SH radiation :bugeye: ??
    2- regarding to what have been said .. can we talk about a lower limit for the black hole's size ?
    3- what about the upper limit for its size too ? does a limit limits the black hole's size and what is the physical property that makes this limit appear ( in case there was a limit ) ??
     
  5. Apr 4, 2010 #4
    No, that's not possible. You have to have sufficient energy in a sufficiently small space to form a black hole :smile:

    http://en.wikipedia.org/wiki/Schwarzschild_radius

    Edit : language confusion… :biggrin:
     
    Last edited: Apr 4, 2010
  6. Apr 4, 2010 #5
    hey there

    i think that what you wrote was in french; the language i hope to learn it one day, but sadly i don't speak it uptil now :frown: !

    and about the wikipedia, i can't take it as a reference so would you please till me what is the exact relevance of schwarzschild redius to our problem ??
     
  7. Apr 4, 2010 #6
    OMG sorry, I don't know what I was thinking writing in french here :biggrin: (I'm on several forums, both in english and in french…)
    What I was saying is that to form a black hole you have to have sufficient energy in a sufficient small space :smile:
     
  8. Apr 4, 2010 #7

    it's ok .. ( sometimes i face the same problem :wink: ), i know that there should be enough energy ( or matter ) in a sphere ( or any volume equal to it ) that has the radius of schwarzschild .. but does this prevent the single atom from forming a black hole ??

    and the rest of my questions if you can help me

    1- what is the SH radiation ??
    2- regarding to what have been said .. can we talk about a lower limit for the black hole's size ?
    3- what about the upper limit for its size too ? does a limit limits the black hole's size and what is the physical property that makes this limit appear ( in case there was a limit ) ??
     
  9. Apr 4, 2010 #8
    Well, yes… What's the mass of one atom ? Calculate its Schwarzschild radius. Conclude… :smile:
     
  10. Apr 4, 2010 #9
    nicely concluded :biggrin:

    but what about the other questions ??

    can you help me answering them ?
     
  11. Apr 5, 2010 #10
    Hawking Radiation (or SH radiation) is a quantum mechanical effect which makes the mass of a black hole get smaller. I don't know the specifics off my head.. (only an undergrad :P) .. but if you look here:
    http://en.wikipedia.org/wiki/Hawking_Radiation
    You should find some sort of explantion.

    as to your other 2 questions, i'm not at all qualified to answer but i'll give it ago anyways :P ..

    a lower limit to a black hole is not theoretically possible, aslong as something has mass, and can be compacted into a suffciently dense state then it can theoretically create a black hole. Which I geuss is the same for an extremly massive object.
    So, my opinion is there is no upper or lower limit to a black hole (aslong as the objects in question have mass)

    Since i'm a noob, i would like some to either verify what i'm saying or point me in the right direction also :D
     
  12. Apr 11, 2010 #11
    Mr. ALYAZAN, Sorry for being late. I see many replies are posted herein .
    1) By 'SH radiation' I meant 'S'tephen 'H'awkings radiation.
    2) & 3) From what i know, it says that contrary to blackholes devouring nature, it still throws out some matter/energy. this is supposed to come from just a bit outwards near event horizon.The smaller a black hole is, more active it is and emits Hawking radiation to death (larger a black hole, more stable it becomes) . Thats why bigger blackholes (are thought to) survive at the center of (almost) every galaxy. there's no upper or lower limit as such.

    (Since I'm a commerce student and learn astrophysics only for interest I might not have replied in 'physics' style.)
     
  13. Apr 11, 2010 #12

    Don't worry about the style .. it is pretty much nice how you write
    and i am thankful for your help, in fact i had searched a lot about it and it seems that your answer is right

    best regards
     
  14. Apr 12, 2010 #13
    Define the word "can".

    If you can compress an atom enough, then yes you can turn into into a black hole, however in the current universe there is no known way of compressing an atom enough, and there is no reason to think that one exists.

    Now if you go into the really early universe, then maybe it's possible.
     
  15. Apr 12, 2010 #14
    I assume this question is regarding future LHC experiments. I am not a physicist but I have read many of the arguments and counterarguments. So I don't pretend to understand the math, this is a summary of what I've read:

    My understanding (others can correct my inaccuracies) is that general relativity places no restrictions on black hole formation simply because it's a single atom. The restrictions are based on mass and density. Anything can become a black hole if it's mass is crushed to a sufficiently small space to create the necessary density. This density requirement for an atom is smaller than the plank scale so it would not be possible to create a black hole. The exception to this is if there are extra dimensions such as those described in string theory. These extra dimensions would increase the size necessary for an atom to be crushed into to something greater than the plank scale. So if string theory is correct then a black hole could be created at the LHC.

    Hawking radiation would (in theory) occur and this would cause the mini-black hole to evaporate (and these black holes are going to be at extremely high temperatures inside the experiment). If Hawking is incorrect and there is no Hawking radiation then it's possible for the mini black holes to stay around indefinitely. However it this were the case then many black holes would have formed in the atmosphere from the collision of cosmic rays. It's been pointed out by many folks that want to stop the LHC that conditions in the atmosphere are different from those in the experiment. While this is true, enough cosmic rays have impacted the atmosphere since the earth was formed that some of these would have created the conditions necessary to replicate the experiment. The fact that we are here (and that none of the other planets have formed into a black hole either) is very strong evidence that the LHC will either not form a black hole or that black holes formed will evaporate.
     
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