# The Big Rip and black holes

**URL:** <https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162>\
**Category:** Factual Questions\
**Created:** [July 23, 2012, 8:16pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162 "2012-07-23T20:16:38Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\
**Post date:** [July 23, 2012, 8:16pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/1 "2012-07-23T20:16:38Z")

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According to a recent article, the universe will probably end when dark energy rips the universe apart. This is bad news for galaxies, solar systems, stars, planets, people, atoms, nuclei, and hadrons- but what about black holes? A black hole has no known structure, but what happens when the red shift limit is less than a black hole’s radius? Is there in fact no dark energy within an event horizon?

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**Author:** ![Yumblie](https://avatars.discourse-cdn.com/v4/letter/y/76d3ee/32.png) [@Yumblie](https://boards.straightdope.com/u/Yumblie)\
**Post date:** [July 23, 2012, 8:50pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/2 "2012-07-23T20:50:32Z")

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What would happen would depend on the explicit properties of both dark energy and the center of black holes, neither of which is known, so we can only speculate. If we posit dark energy as a kind of anti-gravity, then my guess would be that as it got stronger, the event horizon of a black hole would shrink, until you had a naked singularity. If the black hole has any kind of structure it would be ripped apart. If the black hole were literally a singularity with 0 volume then dark energy wouldn’t be able do anything to it from there and it would just be carried through space away from everything else, like every other fundamental particle.

Note that the Big Rip scenario is far from conclusive. Until we better understand dark energy we can’t really say whether we’ll have a long drawn-out Heat Death or an explosive Big Rip ending.

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**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\
**Post date:** [July 23, 2012, 9:35pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/3 "2012-07-23T21:35:53Z")

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Can the OP provide a link? The latest I’ve seen, the dark energy was a constant, overwhelming gravity on intergalactic scales over time, but local groups stayed bound.

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**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\
**Post date:** [July 23, 2012, 10:00pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/4 "2012-07-23T22:00:57Z")

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> [@ZenBeam](#):
>
> Can the OP provide a link? The latest I’ve seen, the dark energy was a constant, overwhelming gravity on intergalactic scales over time, but local groups stayed bound.

> **[Big Rip](https://en.wikipedia.org/wiki/Big_Rip)**
>
> In physical cosmology, the Big Rip is a hypothetical cosmological model concerning the ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, and even spacetime itself,\[clarification needed\] is progressively torn apart by the expansion of the universe at a certain time in the future, until distances between particles will infinitely increase.
> According to the standard model of cosmology, the scale factor of the universe is ac...

And for what it’s worth, Dark Energy (i.e. the expansion of the universe) is not constant over time. It’s commonly believed that early stages of the universe had a much higher rate, which slowed down for a time and then starting increasing again. Since it is still increasing, it’s possible that it will continue to increase to infinity… but since it has slowed down in the past, it’s also possible that it will not continue to increase.

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**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\
**Post date:** [July 23, 2012, 11:32pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/5 "2012-07-23T23:32:14Z")

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An earlier post of mine:  
[http://boards.straightdope.com/sdmb/showthread.php?t=466071&highlight=black+hole](http://boards.straightdope.com/sdmb/showthread.php?t=466071&highlight=black+hole)

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**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\
**Post date:** [July 24, 2012, 5:37pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/6 "2012-07-24T17:37:07Z")

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> [@dracoi](#):
>
> [Big Rip - Wikipedia](https://en.wikipedia.org/wiki/Big_Rip)  
> And for what it’s worth, Dark Energy (i.e. the expansion of the universe) is not constant over time. It’s commonly believed that early stages of the universe had a much higher rate, which slowed down for a time and then starting increasing again. Since it is still increasing, it’s possible that it will continue to increase to infinity… but since it has slowed down in the past, it’s also possible that it will not continue to increase.

The Big Rip is a hypothetical scenario, in which the dark energy is of a specific (‘phantom’) kind; the simplest scenario consistent with observation is indeed that of a cosmological constant, i.e. a term of constant energy density. This yields the so-called lambda-CDM model, often referred to as the ‘standard model of cosmology’ (CDM stands for ‘cold dark matter’, the prevailing hypothesis on the kind of stuff that messes up galactic rotation curves).

As for what happens to black holes, apparently, they dissolve: basically, the phantom energy is accreted by the black hole, which thus looses mass, until it’s gone, or at least so [this article](http://arxiv.org/abs/astro-ph/0505618) argues.

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**Author:** ![fiddlesticks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiddlesticks/32/18129_2.png) [@fiddlesticks](https://boards.straightdope.com/u/fiddlesticks)\
**Post date:** [July 24, 2012, 7:25pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/7 "2012-07-24T19:25:14Z")

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If the recent study is right, the Rip will happen long before decent-sized black holes evaporate, the “worst case” scenario apparently says the Universe has only 17 billion years left.

I presume the dark energy will tear apart black holes too, but I’m guessing there is a Nobel Prize in explaining exactly how that would happen.

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**Author:** ![tetrisd](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@tetrisd](https://boards.straightdope.com/u/tetrisd)\
**Post date:** [March 18, 2014, 8:26am UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/8 "2014-03-18T08:26:14Z")

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> [@](#):
>
> I presume the dark energy will tear apart black holes too, but I’m guessing there is a Nobel Prize in explaining exactly how that would happen.

Could a black hole / singularity torn apart by a big rip look end up looking something like the big bang that started our universe?

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [March 18, 2014, 10:01am UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/9 "2014-03-18T10:01:52Z")

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> [@dracoi](#):
>
> [Big Rip - Wikipedia](https://en.wikipedia.org/wiki/Big_Rip)  
> And for what it’s worth, Dark Energy (i.e. the expansion of the universe) is not constant over time. It’s commonly believed that early stages of the universe had a much higher rate, which slowed down for a time and then starting increasing again. Since it is still increasing, it’s possible that it will continue to increase to infinity… but since it has slowed down in the past, it’s also possible that it will not continue to increase.

How can anything that is finite increase until infinite? Do you mean _increase indefintely_?

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [March 18, 2014, 1:41pm UTC](https://boards.straightdope.com/t/the-big-rip-and-black-holes/629162/10 "2014-03-18T13:41:29Z")

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> [@](#):
>
> How can anything that is finite increase until infinite?

It has a vertical asymptote. Compare to the behavior of the function y = 1/x as you approach the origin from the right.
