What is it Like to Fall into a Black Hole?

And I don’t mean this metaphorically. I’m not talking about a fiscal cliff or a socialist America. I’m bored, frankly, of politics, so I’m spending the next few days reading about cool stuff I don’t understand.

Like Black Holes. And what happens when you fall into them. From Scientific American:

According to current theories of physics, a black hole is mostly just empty space. Its perimeter or “event horizon” is not a material surface, but just a hypothetical location that marks the point of no return. Once inside, you are gripped too tightly by gravity ever to get back out. By then, falling at nearly the speed of light, you have a few seconds to look around before you reach the very center and get crushed into oblivion. But nothing noticeable should happen at the moment of crossing. One of Einstein’s great insights was that observers who are freely falling—whether into a black hole or toward the ground—don’t feel the force of gravity, since everything around them is falling, too. As they say, it’s not the fall that kills you; it’s the sudden stop at the end.

Do you get all stretchy? Unclear:

To the infalling observer, space looks like a vacuum, and in quantum theory, a vacuum is a very special state of affairs. It is a region of space that is empty of particles. It is not a region that is empty of everything. There’s no getting rid of the electromagnetic field and other fields. (If you could, the region would not merely be empty, but nonexistent.) A particle is nothing more or less than a vibration one of these fields, and what makes a vacuum a vacuum is that all the possible vibrations cancel one another precisely, leaving the fields becalmed. To maintain this finely balanced condition, the vibrations must be thoroughly quantum-entangled with one another.

To the outgoing observer, the horizon (or membrane) cleaves space in two, and the vibrations no longer appear to cancel out. It looks like there are particles flying off in every direction. This is perfectly compatible with the infalling observer’s viewpoint, since the fields are what is fundamental and the presence of particles is a matter of perspective. To put it differently, emptiness is a holistic property in quantum physics—true for a region of space in its entirety, but not for individual subregions.

I’m lost. I feel like falling into a black hole can’t be any more baffling than reading about falling into a black hole. But at least I’m not alone:

Someone falling into a black hole doesn’t pass uneventfully through the horizon, but hits a wall of fire and is instantly incinerated. “I think it’s crazy,” [physicist Joe] Polchinski admitted. But in order for a black hole to decay and its contents to spill out, as quantum mechanics demands, the infalling observer can’t see just a vacuum. The firewall idea strikes me as similar to past speculation that black holes are somehow material objects—so-called black stars or dark matter stars—rather than merely blank space.

“I spent 20 years confused by this,” Polchinski said, “and now I’m as confused as ever.” It would be nice to answer the question, if only so that no one ever has to undertake the journey to answer the question.

Actually, I have a better example: after a holiday feast, plump with sugar and animal fat and wine and dairy, I fall into a black hole. On the sofa.

  1. EJHill

    Rob Long… in the Age of Obama

    Age-of-Obama.jpg

  2. EstoniaKat

    I thought the last Star Trek movie settled this.

  3. HerrForce1

    I get a vision of escaping Maximilian Schell and then coming out near Earth…or something.

    Slide1.jpg

    Happy New Year Rob & Ricochet!

  4. Eric Hines

    There are a couple of things, and they have to do with the concept of relativity.  Do you get all stretchy?  Seems clear to me.  From the perspective of your constituent atoms–and their constituents, the protons, electrons, and neutrons (and perhaps from the perspective of their constituents, as well), the gravity gradient varies significantly over the distances involved in traveling from your head to your toes–even from the distances between an atom’s nucleus and its “orbiting” electrons (in quotes because that’s only a way of visualizing things–the location of the electrons–even of the protons and neutrons–is only a probability guess, until something comes along and explicitly looks at them).  Your body does get stretched out as your toes (I’m assuming you jumped into the hole, rather than dove in) are enough closer to the black hole than is your head to experience a significantly stronger pull of gravity.  With your toes accelerating faster than your head, you’re stretching.

    Finally, the canceling is a relative thing, too.  From our perspective, there is smoothness.  From the quark’s perspective, there is much dissonance.  Planck’s Length matters.

    Eric Hines

  5. Casey

    I made the mistake of mentioning this to my wife. Now I have to go vacuum.

  6. Pilli

    Neither light nor matter can escape from a Black Hole ( hence the term “Black” hole and not a midmight blue hole or a dark chocolate hole.)

    So how is it that gravity “escapes” from a Black Hole?

  7. John Walker

    Here is an animation of falling into a black hole.  This is based upon the assumption that the “firewall” doesn’t exist and that crossing the event horizon is no big thing.

    The firewall makes no sense to me.  I understand how a stationary observer near the event horizon would be incinerated by Unruh radiation, but I fail to see any way an in-falling observer crossing the event horizon would perceive anything at all other than the tidal stretch getting a bit more severe.

  8. Eric Hines
    Pilli: Neither light nor matter can escape from a Black Hole ( hence the term “Black” hole and not a midmight blue hole or a dark chocolate hole.)

    So how is it that gravity “escapes” from a Black Hole? · 4 minutes ago

    You’re assuming the gravity originates from within the black hole.

    Eric Hines

  9. James Jones
    John Walker: The firewall makes no sense to me.  I understand how a stationary observer near the event horizon would be incinerated by Unruh radiation, but I fail to see any way an in-falling observer crossing the event horizon would perceive anything at all other than the tidal stretch getting a bit more severe. · 6 minutes ago

    It’s Hawking radiation, not Unruh radiation, that causes the firewall.

  10. flownover

    Ever since Oreck sold the vaccuum company, I am convinced that things just suck in general. Now I see that Hoover is gone, what’s left ?

    I started with  Evelyn Waugh on Nov 7, haven’t looked back. 

    I look up in the sky and wonder why the hell NASA and the USA quit trying to send men up there and satisfied themselves with pictures. Now I know , no voters in outer space.

  11. R. Craigen

    My cats consistently run for their lives when we turn on the vacuum cleaner, fearing they’ll be sucked into a black hole along with the spiders and chunks of candy cane now ground into the carpet.

    Their reaction only serves to illustrate that famous dictum:

    Nature abhors a vacuum.

  12. Raxxalan

    Admittedly it has been a while since I researched this at all. I was under the impression though that beyond the event horizon it is impossible to apply normal physics. The normal constants take on new meaning and things that do not normally have importance in the quantum scale, like gravity, now have a measurable effect. In the end it may be like other fields of physics, Newtonian physics is a reasonable description of the way things work on a global scale; however is insufficient to a universal scale, Relativity works well on a Universal scale but breaks down on a quantum scale. Maybe quantum physics is insufficient to describe the space beyond the event horizon.

  13. Raxxalan

    I believe the firewall theory comes from the fact that black holes radiate a tremendous amount of thermal energy.

  14. Joan of Ark La Tex

    Very elitist suicidal thoughts. Take care. Thanks for entertaining the rest of us though :) 

  15. I. raptus

    The “firewall” idea doesn’t come from Hawking or Unruh radiation.  No, the firewall idea comes from an attempt to play around with string theory.  Quantum mechanics and general relativity are both very well grounded (incredibly so) in experiment, but string theory has yet to make a single falsifiable prediction (except, one could argue, ones that appear to be wrong, such as predicting too many dimensions).  So trying to figure out what it says about the interior of a black hole seems premature, since that’s really untestable — even if you could jump in a nearby black hole, survive the external radiation and tides, and come close enough to the singularity to really experience whatever quantum gravity effects might be waiting for you, there’s no way you could communicate what you found (even or even signal that you died early by hitting this “firewall”) to the outside, because you’re inside a horizon.

    All this is rather academic.  Any stellar-massed black hole you fell into would have enough matter around it that it’d fry you before you got near the horizon and tides strong enough that you’d be torn apart before you got near the singularity.

  16. I. raptus

    As for the question of how gravity “gets out” of a black hole, the answer is it was there to begin with as the black hole formed.  Gravity is just spacetime curvature in general relativity, and if you have a collapsing star (or whatever) that will eventually form a star, spacetime is curved around it and as it gets more and more dense, the spacetime around is still there and curved more, until finally it falls within its own Schwarzschild radius*.  The gravity is still there because the spacetime is still there, and still curved, even though all you see is a horizon.

    * People can quibble with this phrasing since to external observers one can make points about the Schwarzschild t coordinate vs. proper time, but you know what I mean.

  17. Percival
    James Lileks:

    In the theory of Lorentzian manifolds, spherically symmetric spacetimes admit a family of nested round spheres. In such a spacetime, a particularly important kind of coordinate chart is the Schwarzschild chart, a kind of polar spherical coordinate chart on a static and spherically symmetric spacetime, which is adapted to these nested round spheres.

    Static, spherically symmetric spacetimes? 

    Ptolemaicsystem-small.png

    Claudius Ptolemaeus, thou art avenged.

  18. Hank Rhody
    James Lileks: As a casual consumer of pop cosmology, I’ve come to believe in the multiverse model, the “soap bubbles” construct [...] It’s more emotionally satisfying than the one-shot / heat-death model, which makes me distrust my conclusions: science isn’t right just because it feels right. [...]

    Really? I tend to reject the multiverse model precisely because I find it less emotionally satisfying. Specifically, it allows hack writers cover for their laziness.

    With respect to a rationale for an iterated universe, In Arthur C. Clarke’s later Rama novels he suggests that god spins out universes in order to determine the set of all possible starting conditions that would eventually lead to a harmonious outcome. It’s a staggering idea, but I always thought his god was too small. When I say “omniscient” I mean omniscient.

  19. flownover
    Joan of Ark La Tex: Very elitist suicidal thoughts. Take care. Thanks for entertaining the rest of us though :)  · 14 minutes ago

    Elitist suicidal thoughts ? I read that and applied to my life. It worked .

    If I were to buy my wife a new vacuum as a present , it would be suicidal . (how many words have two ‘u’ in a row ?)
  20. Joan of Ark La Tex
    flownover

    Joan of Ark La Tex: Very elitist suicidal thoughts. Take care. Thanks for entertaining the rest of us though :)  · 14 minutes ago

    Elitist suicidal thoughts ? I read that and applied to my life. It worked .

    If I were to buy my wife a new vacuum as a present , it would be suicidal . (how many words have two ‘u’ in a row ?) · 2 minutes ago

    I tend to agree with Craigen. Everything from nature’s perspective, about the vacuum, pretty much, sucks.