“When a person starts to talk about their dreams, it’s as if something bubbles up from within. Their eyes brighten, their face glows, and you can feel the excitement in their words.” -John C. Maxwell

One of the most remarkable features of a great number of giant, active galaxies are the presence of jets of hyper-accelerated matter, spanning thousands of light years. Correlated with feeding, supermassive black holes are these huge structures of light-emitting matter, identifiable from many millions of light years away.

The giant elliptical galaxy, M87, and its 5,000+ light year-long jet, highly collimated, as imaged by the Hubble Space Telescope. Image credit: NASA and The Hubble Heritage Team (STScI/AURA).

The giant elliptical galaxy, M87, and its 5,000+ light year-long jet, highly collimated, as imaged by the Hubble Space Telescope. Image credit: NASA and The Hubble Heritage Team (STScI/AURA).

Yet our best simulations show that the gas temperature rises around them not in jet-like streams, but rather in spherical explosions around these supermassive black holes. Is there an incredible disconnect between the two pictures? There might have been if you had asked only 15 years ago, but the physics of radiative feedback has evolved tremendously thanks to advances in numerical simulations, allowing us to explain this phenomenon after all.

Messier 87 in X-ray and radio. Image credit: X-ray: NASA/CXC/KIPAC/N. Werner et al Radio: NSF/NRAO/AUI/W. Cotton.

Messier 87 in X-ray and radio. Image credit: X-ray: NASA/CXC/KIPAC/N. Werner et al Radio: NSF/NRAO/AUI/W. Cotton.

Go get the answer to Robert Coolman’s difficult question on this edition of Ask Ethan!

Comments

  1. #1 Omega Centauri
    March 26, 2016

    That was unsatisfying. The gas responds primarily because it get heated, and one would expect the heating would need to be spherically symmetric in order for the “explosion” to be spherically symmetric. Now I think it should be intuitively obvious that the jet will simply blast through the gas, so whatever else happens we have holes punched out by the jets. Then the problem becomes one of explaining why the rest of the energy is deposited in the gas in a roughly spherical manner. Presumably, this energy comes from the accretion disk.

    Gas temperature, as a graphic is a bit hard to grasp mentally, given the fact that the density probably varies by orders of magnitude.

  2. #2 Ben Fulton
    March 27, 2016

    This process on a larger scale is dark energy. A Universal black hole is powering the Universal lobe we exit in.

  3. #3 Denier
    United States
    March 30, 2016

    The jets extending out from these black holes show the magnetic field that caused them has been very stable for a long, long time. If nothing other than gravity can escape a black hole, how does that work? Is magnetic information allowed to travel faster than light or is this just another case where we pretend the black hole never collapses further than the event horizon so as to keep the math from breaking?

  4. #4 Naked Bunny with a Whip
    March 30, 2016

    @Denier #3: My understanding is that the magnetic field doesn’t disappear when a star collapses into a black hole, just like the star’s mass and angular momentum don’t disappear.

  5. #5 Denier
    United States
    March 30, 2016

    @Naked Bunny with a Whip #4

    I follow what you are saying, but information about the mass is conveyed by gravity. The information about the angular momentum is conveyed, if I understand correctly, by the effect frame dragging has on the inner edge of the accretion disc. Both of those are warpages of space-time, but electromagnetism is not. Electromagnetic information is conveyed via the photon, and those are not allowed to escape a black hole.

    Aside from photons not being able to escape, dimension become time-like at the event horizon. That means there isn’t even a path through space for magnetic lines of force to reach from the collapsed object to the space around the black hole.

    Even going with the idea the object never collapsed further than the event horizon so the magnetism is all coming from the shell has problems. By that same logic black holes wouldn’t be black because they were emitting great quantities of light too when they were that size. If the electromagnetic force carriers are still evident then why wouldn’t the photons of light still be just as present as the magnetic field?

  6. #6 Denier
    United States
    March 31, 2016

    After thinking about this overnight, here is my theory on why black holes have magnetic fields:

    1 – Space-Time doesn’t actually warp. That is just a visualization we use to comprehend the phenomenon of gravity. Instead gravity is probabilistic in nature and at the event horizon the probability of movement toward the singularity becomes 100%. After crossing the EH, there is a 0% chance of movement in any other direction other than toward the singularity for gravitationally effected objects.

    2 – Magnetic fields are implemented by VIRTUAL photons. The photon has zero rest mass, and the virtual photon also has no energy. This is why the projection of a magnetic field in and of itself does not diminish the energy or mass of the magnetic object.

    3 – Because virtual photons have no rest mass and no energy they are not effected by gravity. Real photons cannot escape a black hole because of their energy, but magnetic force carrier photons can.

    4 – If you had a radio on the inside of a black hole that transmitted information by switching on and off a magnetic field, that information could be received outside the black hole. The information could not cover the distance faster than 186,000 miles per second, but in this special case the rate of transmission is infinitely faster than the speed of light.

  7. #7 Denier
    United States
    April 1, 2016

    5 – Some magnetic force carrier photons emanating from the collapsed object do gain energy in the zone immediately outside the event horizon to become Hawking Radiation. Those produced particles not only diminish the mass-energy of the collapsed object, but the mechanism creates an information link between the collapsed object and zone of particle production thereby solving the information paradox.

  8. #8 wow
    April 2, 2016

    “1 – Space-Time doesn’t actually warp.”

    Possibly, but only in so far as to map onto euclidian space and “classical” time, you have to do a transform from reality to your model.

    Just like you have to convert to spherical coordinates to map wandering on the surface of a sphere.

    However, this doesn’t stop reality having discontinuities and infinities and unavailable locations when we walk on the planet earth. Try walking away from the planet without an engine. You can’t.

    Just like you can’t get out of a black hole.

    So though it may be a fiction, it’s not changing anything important.

  9. #9 Sinisa Lazarek
    April 2, 2016

    @ Denier

    I’m not sure what were the premises that lead you to your points 1, 2,3 .. 5 but just at a first glance there seem to be some problems

    1. while the idea of probabilistic gravity isn’t unheard of. Just postulating that spacetime doesn’t warp but instead is something else, without any proof of links to proof isn’t very satisfactory. On the other hand, if all effects are same, doesn’t matter what you call it. The problem I have with probabilistic gravity is that naively speaking, you can’t have 100% probability anywhere if you take QM into consideration. So every now and then (however long that then is) you would have particles defying gravity. Because there is i.e. 0.000000000000000000000000001% chance that the trajectory it takes is not the same as 99.99…% of the time. The combined effect of that should be noticeable.

    2. the properties of virtual photons are such that the interaction you describe is very short range and applies to QM style dipole. A bar magnet is not emanating virtual photons like a flashlight.

    3. “Because virtual photons have no rest mass and no energy they are not effected by gravity.” – this is speculation. On the other hand, virtual photons can’t exists by themselves. They don’t actually exists.. hence virtual.. If something has no mass and no energy.. then it doesn’t really exists in our physical world.

    4. is extrapolation from no.3 but is in opposition to no.1.. If it has energy, then it’s path is 100% towards singularity, that’s what you said. It’s a catch 22 really.. if it has energy, it warps space. If it doesn’t have energy.. then we don’t care about it 🙂 So your magnetic field that isn’t interacting with spacetime requires a new theory, because it’s in conflict with current ones.

    5. the hawking radiation can be understood maybe more clearly if you think of dynamical cassimir effect where the horizon of a black hole is the moving plate. Because acceleration and graviation are same due to equivalance principle.

  10. #10 Denier
    United States
    April 2, 2016

    @Sinisa Lazarek

    I’ve got faster than light communication and have solved the black hole information paradox. There have to be problems, I’m just not versed enough to find them.

    1 – The reason for probabilistic gravity is to create a path through space for a non-gravitationally effected construct.

    2 – As I understand them, virtual photons are mathematical placeholders for an exchange of electromagnetic information. The exchange uses no energy from either end of the link, but behaves mathematically as if photon has crossed the distance between the 2 objects in communication.

    3 – It is speculation, but testable. Just as you’d get a detectable frequency bias in light with light traveling away from a gravitational source versus toward a gravitational source, there would be a bias in the strength of a magnetic field toward a gravitational source. It is my speculation that there is no such bias because the mechanism that conveys magnetic force is not effected by gravity. As for things that have no mass and no energy not being real, if that were so then magnetic attraction across a vacuum wouldn’t be real.

    4 – The new theory is that for non-gravitationally effected constructs that spacetime is flat regardless of the presence of a gravitational field.

    5 – The how of Hawking Radiation isn’t nearly as important as the possible mechanism for creating a communication between the collapsed object and the zone of particle production.

    LIke I said at the outset, I know it is probably wrong and was hoping I could put it into terms that weren’t too word-salady so that smarter people could point out the errors. I do want to thank you for tackling it.

  11. #11 Wow
    April 11, 2016

    “3. “Because virtual photons have no rest mass and no energy they are not effected by gravity.” – this is speculation.”

    It’s also wrong.

    They do get retarded and their energy reduced as they come out of a gravitational well, if they were not to do so, they would not operate the same way as they are observed to, quite radically.

  12. #12 Wow
    April 11, 2016

    “There have to be problems, I’m just not versed enough to find them.”

    Then you don’t have a theory and nobody has to care one whit as to your wild theorising.

  13. #13 Denier
    United States
    April 11, 2016

    @Wow #11

    They do get retarded and their energy reduced as they come out of a gravitational well, if they were not to do so, they would not operate the same way as they are observed to, quite radically.

    We seem to have yet another example thread in which you display that you don’t understand what a virtual particle is. Virtual photons are not observed at all. Seeing as you do seem to understand math you can do the calculations for yourself.

    How much gravitational acceleration takes place when the time elapsed is zero? The same properties that keep them from violating conservation of energy mean they don’t exist long enough to be accelerated (or have their borrowed energy reduced) by gravity.

    Your insistence in treating virtual particles like tiny bullets of matter is getting you in trouble.

  14. #14 eric
    April 11, 2016

    Denier, it’s not a binary categorization. If a virtual particle lasts long enough, it is effectively a ‘normal’ particle and obeys all the normal laws of physics. They are simply typically at the “short lifetime” end of the scale, and as such, have a very indefinite properties.

    I can’t think of any particular examples of gravity influencing them because its such a weak force. However there is to prima facie reason why it couldn’t; if you’re calculating wavefunctions and fields, anywhere they overlap would be an area where they could interact and thus gravity could influence the VP. When you talk about how much gravitational acceleration a virtual particle could feel zero time, it is you who are thinking about VPs as billiard balls, not Wow.

  15. #15 Denier
    United States
    April 11, 2016

    @eric #14

    Denier, it’s not a binary categorization. If a virtual particle lasts long enough, it is effectively a ‘normal’ particle and obeys all the normal laws of physics. They are simply typically at the “short lifetime” end of the scale, and as such, have a very indefinite properties.

    I’d be very interested if you could provide any support for this. From all the reading I’ve done, it is very binary. Virtual particles are absolutely NOT real particles. Mathematically particles are on-shell or off-shell. There is no kinda-shell or semi-shell. There is no gravitational acceleration of virtual particles because as off-mass-shell entities by definition they do not satisfy classical equations of motion.

    They aren’t on the short lifetime end of the scale like a top quark. VP are not on the scale at all. Phenomenologically they are said to exist for a duration shorter than Planck time so as to keep from violating physics. Quantum mechanically speaking there is no time in our universe shorter than Planck time.

    @eric

    I can’t think of any particular examples of gravity influencing them because its such a weak force. However there is to prima facie reason why it couldn’t

    I’ve already brought up the mathematical problem of accelerating (gravitation and acceleration is indistinguishable) off-shell constructs, but we also have these magnificent jets emanating from the poles of supermassive black holes. That is pretty prima facie.

    @eric

    When you talk about how much gravitational acceleration a virtual particle could feel zero time, it is you who are thinking about VPs as billiard balls, not Wow.

    No confusion here. They’re not billiard balls. They’re not particles at all and the name is rather unfortunate because of the confusion it causes.

    If you can back up your post, I’m willing to listen.

  16. #16 Denier
    United States
    April 11, 2016

    @eric #14

    As an addendum: I’m am aware of Hawking Radiation. It doesn’t solve the problem of accelerating off-mass-shell “particles”.

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