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Thread: Stephen Hawking last work

  1. #91
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    Quote Originally Posted by Sinbad View Post
    So how do we know that 10’28 is not the smallest that can exist?
    We've never seen a black hole with a mass less than 10^31 kg. In theory smaller ones could exist, but there is no demonstrated path toward making one smaller.
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  2. #92
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    Quote Originally Posted by antoniseb View Post
    We've never seen a black hole with a mass less than 10^31 kg. In theory smaller ones could exist, but there is no demonstrated path toward making one smaller.

    So basically primordial black holes are just now evaporating and have happened before then?

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    Quote Originally Posted by Sinbad View Post
    So basically primordial black holes are just now evaporating and have happened before then?
    There is no evidence that primordial black holes exist.

    We have no evidence that they have ever, are now or will ever evaporate. And if they do, as far as we know they will just create a flash of light.

  4. #94
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    Quote Originally Posted by Sinbad View Post
    So basically primordial black holes are just now evaporating and have happened before then?
    There is no evidence that primordial black holes exist, or even that black holes (primordial or not) evaporate. If black holes do evaporate, they have been doing so since the first black hole was formed, but IF there are no black holes formed at less than 10^31 kg, AND black holes do evaporate, no black holes have ever evaporated out of existence yet. Only a black hole less than 10^12 kg (1 trillion kg) or less formed at roughly the time of the big bang would have had time to evaporate out of existence by now, but the smallest black hole known is 10^19 (10 sextillion) times bigger than that.
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    Quote Originally Posted by antoniseb View Post
    There is no evidence that primordial black holes exist, or even that black holes (primordial or not) evaporate.
    That's a good point. We generally assume that Hawking radiation happens but that has not been confirmed.

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    I am confused because according to the articles and YouTube video Dr Mack says that the primordial bh of 10’18 are now fondu hung evaporating

  7. #97
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    Quote Originally Posted by Sinbad View Post
    I am confused because according to the articles and YouTube video Dr Mack says that the primordial bh of 10’18 are now fondu hung evaporating
    Ask Dr. Mack for ANY evidence that this is happening. There isn't any.
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    Quote Originally Posted by Sinbad View Post
    I am confused because according to the articles and YouTube video Dr Mack says that the primordial bh of 10’18 are now fondu hung evaporating
    Please provide a link to an article where she says this.

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    Quote Originally Posted by Strange View Post
    Please provide a link to an article where she says this.
    I provided the YouTube video from her at mark 30m and also a couple of articles already for you?

  10. #100
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    Quote Originally Posted by Sinbad View Post
    I provided the YouTube video from her at mark 30m and also a couple of articles already for you?
    But you know she's talking about a chain of theoretical reasoning, not something that's actually observed to be happening. Right?

    Grant Hutchison

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    Her YouTube and articles seems to be pretty sure

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    Quote Originally Posted by Sinbad View Post
    Her YouTube and articles seems to be pretty sure
    Pretty sure of the theoretical reasoning, yes. And then the theory is in conflict with observation, which undermines the theory. So the conclusion is that these theoretical things are not happening. We've been through this.

    ETA: You made me watch the damn video. Immediately after describing black hole evaporation she says, "We don't know that. It's kinda fun." How you can interpret that as her being "pretty sure" is beyond me.

    Grant Hutchison

  13. #103
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    Quote Originally Posted by Sinbad View Post
    I provided the YouTube video from her at mark 30m and also a couple of articles already for you?
    Primordial black holes are still hypothetical, actual discovery would be big news.

    I checked the video. It is a bit after 30m, but it is clear she is just saying that if such mass black hoes existed, that they would be evaporating away now. I was a little disappointed she didnít mention that Hawking radiation is theoretical, not observed, so we canít know if black holes evaporate yet.

    She did mention that evaporation of a black hole may trigger vacuum decay. She did not suggest that was established.

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  14. #104
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    Naturally Grant beat me to it. Grumble.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." ó Abraham Lincoln

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    As I mentioned her videos and article claim it’s real and happening.
    If you read some of her recent work it claims the same with facts I posted a few articles and I am sure there are more out there.
    Grant posts a few articles which went over my head do not sure what she is saying.

  16. #106
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    Quote Originally Posted by Sinbad View Post
    As I mentioned her videos and article claim it’s real and happening.
    Are you still talking about primordial black hole evaporation? If so, I would like to see some specific quotes. It’s clear you misunderstood what she was saying on the video. It is easy to miss things in a video (one of the reasons I much prefer text to hearing someone drone on about a technical subject).

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  17. #107
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    Quote Originally Posted by Sinbad View Post
    As I mentioned her videos and article claim it’s real and happening.
    No, they don't. You presumably heard her say in the video, after talking about black hole evaporation and vacuum decay, "It may be [...] We don't know that. [...] Kinda fun." So she is very much not claiming that it's real and happening. Why would you think she was?

    Grant Hutchison

  18. #108
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    On the video:

    https://www.youtube.com/watch?v=HETB...ature=youtu.be

    Go to the 31 minute mark. A few seconds after, she mentions the mass of the black hole, and she says “if they were formed at the beginning of the universe, they would be evaporating now.” Check it out, listen for the “if.” She continues on about how that might cause vacuum decay.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." ó Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

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  19. #109
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    Quote Originally Posted by Van Rijn View Post
    On the video:

    https://www.youtube.com/watch?v=HETB...ature=youtu.be

    Go to the 31 minute mark. A few seconds after, she mentions the mass of the black hole, and she says “if they were formed at the beginning of the universe, they would be evaporating now.” Check it out, listen for the “if.” She continues on about how that might cause vacuum decay.
    Her mass of black hole is accurate and the theory of this falls into lines of what she is saying. So basically theory is that black hole is evaporated and false vacuum can occur right now?

    Also black hole size and timing fall into what wiki says about it.
    This falls into her any moment comment

  20. #110
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    Quote Originally Posted by Sinbad View Post
    Her mass of black hole is accurate and the theory of this falls into lines of what she is saying. So basically theory is that black hole is evaporated and false vacuum can occur right now?
    We've been through all this.

    One last time. If these primordial black holes existed, and if they evaporated through Hawking radiation, then hypothetical black holes of mass 10^12 kg would be evaporating right now. All the less massive primordial black holes would already have evaporated. If the evaporation of primordial black holes caused collapse of the false vacuum, then they would have done so already, during some earlier epoch. This has not happened.

    All of that has been explained already. If you keep ignoring the explanations, I imagine people will stop giving them.

    Grant Hutchison

  21. #111
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    OK, this has gone on long enough. There have been numerous explanation of black holes and vacuum decay in this thread. There have been numerous interpretations of what Katie Mack is saying. You have been told numerous times that you are more likely to get eaten by parrots than there will be a vacuum decay. And that's just this thread - not to mention the several other threads you have had on these very same topics. Repeating the same explanations over and over again is not getting anywhere.

    Please do not bring up this video or this same question again.
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