# Escaping a black hole **URL:** \ **Category:** Factual Questions\ **Created:** [April 16, 2005, 2:20pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626 "2005-04-16T14:20:59Z")\ **Posts on this page:** 20\ **Page:** 3
**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 20, 2005, 6:31am UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/41 "2005-04-20T06:31:09Z")
Correction: Nothing in our observations suggest the existance of singularities. Our observations do suggest black holes, and the simplest models of black holes all contain singularities. It is possible or even likely that quantum gravitational effects might prevent a singularity from forming, in which case the center of a black hole would be a very small region of insanely high but finite density, instead of a zero-size, infinite density singularity. In either event, however, the central core of a black hole is well inside the event horizon (at least for any black hole of astrophysical origin, which are the only ones we have any evidence for), so it doesn’t much matter whether it’s a singularity or not. And there are some serious scientists, working in the field of relativity, who legitimately doubt the existance of black holes. These scientists put forth vague quantum gravitational conjectures containing almost-black hole objects such as the so-called “gravatars” or “dark energy stars”. Such black hole skeptics are rare, and I and most other relativists think they’re wrong, but they are genuine scientists working in good faith. Then again, I doubt that there’s any scientific theory which commands truly unanimous acceptance by all scientists in that field, so I don’t think it’s too relevant to note the doubters. ---
**Author:** ![Loopydude](https://avatars.discourse-cdn.com/v4/letter/l/e56c9b/32.png) [@Loopydude](https://boards.straightdope.com/u/Loopydude)\ **Post date:** [April 20, 2005, 12:32pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/42 "2005-04-20T12:32:22Z")
Thanks **Mathochist** and **Chronos**! Those answers are (believe it or not!) quite helpful. At least, I think! ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [April 20, 2005, 2:46pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/43 "2005-04-20T14:46:47Z")
> [@Stranger On A Train](#): > > Some physicsts have suggested that electrons are actually Planck-mass charged singularities, though those claims are entirely speculative. Really? Planck mass? A Planck mass is many orders of magnitude more than the mass of an electron. ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [April 20, 2005, 4:55pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/44 "2005-04-20T16:55:15Z")
> [@CurtC](#): > > Really? Planck mass? A Planck mass is many orders of magnitude more than the mass of an electron. I think it might be explained by the fact that masses do weird things in the quantum world. For instance, the mass of a nucleon is very different from the sum of the masses of its three constituent quarks, the rest being made up of binding energies. Also, remember that mass-energies, strictly speaking, aren’t real numbers but elements of an **R** -torsor – you can take their difference but you can’t really add them. ---
**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 20, 2005, 7:04pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/45 "2005-04-20T19:04:13Z")
Heck, I suppose that renormalizing away a Planck mass is no worse, really, than the more usual trick of renormalizing away an infinite mass. But you’re right to call such claims speculative: So far, none of them have advanced beyond the status of a toy model. That is to say, such microscopic black holes would have some of the properties of subatomic particles, and it can be instructive to study such similarities, but nobody has yet figured out a way to make them have all of the right properties. May I add, **Mathochist** , that your last line there completely lost me. ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [April 20, 2005, 7:09pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/46 "2005-04-20T19:09:54Z")
> [@Chronos](#): > > May I add, **Mathochist** , that your last line there completely lost me. It rather throws most people at first, but really makes a lot more sense once you grok G-torsors. Essentially, given a group G a G-torsor is a G-space which is isomorphic to G with the standard right action. An affine space is a V-torsor for the vector space with which it’s usually confounded. I don’t want to go way too far afield from the OP here, but you can search on Baez’ [This Week’s Finds](http://math.ucr.edu/home/baez/TWF.html) archive or start a new thread for discussing torsors in general. ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [April 20, 2005, 8:26pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/47 "2005-04-20T20:26:57Z")
My head a splode. ---
**Author:** ![Happy\_Fun\_Ball](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/happy_fun_ball/32/17664_2.png) [@Happy\_Fun\_Ball](https://boards.straightdope.com/u/Happy_Fun_Ball)\ **Post date:** [April 20, 2005, 10:09pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/48 "2005-04-20T22:09:41Z")
> [@Mathochist](#): > > It rather throws most people at first, but really makes a lot more sense once you grok G-torsors. Essentially, given a group G a G-torsor is a G-space which is isomorphic to G with the standard right action. An affine space is a V-torsor for the vector space with which it’s usually confounded. I don’t want to go way too far afield from the OP here, but you can search on Baez’ [This Week’s Finds](http://math.ucr.edu/home/baez/TWF.html) archive or start a new thread for discussing torsors in general. Youch! ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 20, 2005, 10:24pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/49 "2005-04-20T22:24:04Z")
> [@Chronos](#): > > Correction: Nothing in our observations suggest the existance of singularities. Our observations do suggest black holes, and the simplest models of black holes all contain singularities. It is possible or even likely that quantum gravitational effects might prevent a singularity from forming, in which case the center of a black hole would be a very small region of insanely high but finite density, instead of a zero-size, infinite density singularity. I stand corrected of equating “black hole” with “singularity”. Any sufficiently (relatively) compact, highly massive object could have an event horizon. At any rate, the theory (that electrons could be micro black holes) is entirely speculative, a plaything of string theorists and other bleeding edge cosmologists. It also bears noting that such a tiny black hole should be unstable and evaporate into Hawking radiation in short order (like, fractions of picoseconds or faster) and therefore proponents have to come up with some unknown mechanism which retards evaporation. Stranger ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [August 27, 2009, 4:04pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/50 "2009-08-27T16:04:39Z")
> [@Reeder](#): > > I think we should keep in mind that Black Holes are still purely theoretical. > > Not every space scientist believes they exist. Actually, that isn’t quite true. [Some photos.](http://hubblesite.org/newscenter/archive/releases/2000/20/image/a/) [More photos](http://science.nationalgeographic.com/science/photos/black-holes-gallery/perseus-black-hole.html) Although there may be scientists who would argue that these things are something other than what we consider black holes. > [@Chronos](#): > > If you’re falling in, you have a finite (and distressingly short) amount of time, in your reference frame, before you reach the singularity, and you’ll cross the event horizon in an even shorter amount of time. Discussions of “outside observers” usually mean observers who are not falling in; any observer not falling in can’t see anything past the horizon. As you’re falling in, you can always see your feet, but any photons which left your feet from inside the horizon will only reach your eyes after they’re inside the horizon, too. And after you pass the horizon, your feet aren’t pointing “in” any more, since “in” becomes a timelike direction. Instead, your feet would end up pointing along the t direction, which is now a spacelike direction. You wouldn’t know it with a large enough black hole though. With a supermassive black hole, the change in tidal forces is small enough that you would have no idea that you crossed the event horizon. [Here is a link to some interesting videos I posted in a similar thread on what you might see going in.](http://jilawww.colorado.edu/~ajsh/insidebh/schw.html) ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [August 27, 2009, 4:28pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/51 "2009-08-27T16:28:04Z")
> [@msmith537](#): > > You wouldn’t know it with a large enough black hole though. With a supermassive black hole, the change in tidal forces is small enough that you would have no idea that you crossed the event horizon. What happen if your waist and below is inside the event horizon and the rest of you is outside of it? ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [August 27, 2009, 5:07pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/52 "2009-08-27T17:07:29Z")
> [@Whack-a-Mole](#): > > What happen if your waist and below is inside the event horizon and the rest of you is outside of it? You couldn’t hover there, if that’s what you’re thinking. You’d be falling through the event horizon at nearly the speed of light. If a zombie bit your toe, by the time your head realized it, your head would be inside the event horizon as well. ---
**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:** [August 27, 2009, 5:47pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/53 "2009-08-27T17:47:41Z")
> [@](#): > > If a zombie bit your toe… I see what you did there. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [August 27, 2009, 5:54pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/54 "2009-08-27T17:54:29Z")
> [@ZenBeam](#): > > You couldn’t hover there, if that’s what you’re thinking. You’d be falling through the event horizon at nearly the speed of light. If a zombie bit your toe, by the time your head realized it, your head would be inside the event horizon as well. Aren’t I hanging on to my unobtanium rope tethered to my ship some distance away and climbing into the BH slowly? ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [August 27, 2009, 10:11pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/55 "2009-08-27T22:11:23Z")
> [@Whack-a-Mole](#): > > Aren’t I hanging on to my unobtanium rope tethered to my ship some distance away and climbing into the BH slowly? No, sorry. You, your rope, and your ship have all slipped below the event horizon. You only have seconds to live… ---
**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:** [August 27, 2009, 10:22pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/56 "2009-08-27T22:22:08Z")
> [@](#): > > Aren’t I hanging on to my unobtanium rope tethered to my ship some distance away and climbing into the BH slowly? No, in fact you’re not. If you try to do so, then eventually your rope will break before you reach the horizon. ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [October 3, 2009, 9:54am UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/57 "2009-10-03T09:54:27Z")
There was a recent article in Scientific American positing that instead of black holes there are actually black stars. From a distance they look the same, but up close there is no event horizon and no singularity of infinite density. There are a few hypotheses describing the exact mechanism of black stars, but they are all merely extremely dense rather than infinitely so, and light can escape them. This would account for observations of Hawking radiation from suspected black holes. These various hypotheses are an attempt to reconcile relativity and quantum theory, and also resolves the problem with regular black hole theory that allows information to be destroyed at the event horizon. Link: [http://www.scientificamerican.com/article.cfm?id=black-stars-not-holes](http://www.scientificamerican.com/article.cfm?id=black-stars-not-holes) ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 3, 2009, 10:47am UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/58 "2009-10-03T10:47:44Z")
> [@Bytegeist](#): > > I believe the black hole hypothesized (or confirmed?) to exist at the center of the Milky Way is large enough to produce this effect — or lack of effect, as the case may be. > > The mass of this black hole is a whopping [3.6 million solar masses](http://www.mpe.mpg.de/ir/GC/index.php), giving it a Schwarzschild radius of about 11 million km. The [tidal force](http://math.ucr.edu/home/baez/PUB/tidal) on a human-sized body at that distance would be about 0.0015 m/s[sup]2[/sup], which is a tiny fraction of the “1 g” force you feel on the surface of the earth. > > So, no spaghettification when passing through _that_ monster’s event horizon. In fact, you’d hardly feel a thing. > > (Someone feel free to check my math, or reasoning.) From the point of view of someone just inside that radius, then, what would it look like? I imagine it would appear as though the universe outside the radius begins to accelerate away from me at a rate that makes it impossible for me to catch up? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 3, 2009, 4:29pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/59 "2009-10-03T16:29:36Z")
> [@sturmhauke](#): > > There was a recent article in Scientific American positing that instead of black holes there are actually black stars. From a distance they look the same, but up close there is no event horizon and no singularity of infinite density. There are a few hypotheses describing the exact mechanism of black stars, but they are all merely extremely dense rather than infinitely so, and light can escape them. This would account for observations of Hawking radiation from suspected black holes. There has been no Hawking radiation observed from black holes, as for any stellar-mass black hole the Hawking radiation would be insignificant compared to other effects. Stranger ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 3, 2009, 5:17pm UTC](https://boards.straightdope.com/t/escaping-a-black-hole/299626/60 "2009-10-03T17:17:50Z")
> [@Whack-a-Mole](#): > > What happen if your waist and below is inside the event horizon and the rest of you is outside of it? It would either break off or pull the rest of you through the event horizon. [Previous page](https://boards.straightdope.com/t/escaping-a-black-hole/299626.md?page=2)