# black hole white hole **URL:** \ **Category:** Factual Questions\ **Created:** [April 2, 2003, 5:29pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002 "2003-04-02T17:29:18Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![shea241](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@shea241](https://boards.straightdope.com/u/shea241)\ **Post date:** [April 2, 2003, 5:29pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/1 "2003-04-02T17:29:18Z")
How do they know that a white hole isn’t some kind of exit for a black hole. If just as a black hole can only suck things in, a white hole can only spit things out. The white hole needs material to be spitting things out of and if black holes could warp space and maybe create a wormhole maybe thats how a whitehole could be created??? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 2, 2003, 5:36pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/2 "2003-04-02T17:36:18Z")
Which white holes are you referring to? I am not aware of any confirmed examples. ---
**Author:** ![shea241](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@shea241](https://boards.straightdope.com/u/shea241)\ **Post date:** [April 2, 2003, 5:42pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/3 "2003-04-02T17:42:22Z")
I’m talking about the white hole that you get from the fact that the equations of general relativity have an interesting mathematical property: they are symmetric in time. That means that you can take any solution to the equations and imagine that time flows backwards rather than forwards, and you’ll get another valid solution to the equations. If you apply this rule to the solution that describes black holes, you get an object known as a white hole. ---
**Author:** ![Earthworm\_Jim](https://avatars.discourse-cdn.com/v4/letter/e/f07891/32.png) [@Earthworm\_Jim](https://boards.straightdope.com/u/Earthworm_Jim)\ **Post date:** [April 2, 2003, 5:44pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/4 "2003-04-02T17:44:12Z")
From [Curious About Astronomy](http://curious.astro.cornell.edu/question.php?number=108) > [@](#): > > In the full, and most simple General Relativistic solution for a space-time which has a Black Hole (in a vacuum), there are two singularities. One is in what we call the ‘future-light cone’ and this is the Black Hole. The other is in the ‘past-light cone’ and is called a White Hole. This solution is however completely unphysical in many ways and in a real Black Hole (formed from the collapse of a star for example) we cannot use the vacuum solution as there is matter present, and the White Hole singularity disappears. > So the answer to your question is that there is only such a thing as a White Hole in the theory of Black Holes and no such thing is possible physically. So, unless you’re asking purely mathematically, the question appears meaningless. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [April 2, 2003, 7:59pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/5 "2003-04-02T19:59:18Z")
I think somebody’s been watching too much “Red Dwarf”. 🙂 ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [April 2, 2003, 10:45pm UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/6 "2003-04-02T22:45:44Z")
> [@](#): > > \*Originally posted by Jeff Olsen \* > \*\*I think somebody’s been watching too much “Red Dwarf”. 🙂 \*\* No such thing! ---
**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:** [April 3, 2003, 6:38am UTC](https://boards.straightdope.com/t/black-hole-white-hole/166002/7 "2003-04-03T06:38:12Z")
Two problems: First, if there were a white hole anywhere in the observable Universe, then we’d see it. Dem tings is BRIGHT! Second, there’s no reason to believe that the matter which falls into a black hole “drains” to anywhere. It just adds to the mass of the hole. If it drained, then black holes would rather quickly lose mass, which doesn’t seem to occur.