John Wheeler in 1981 characterized a black hole as “Mass without matter”. (Proceedings of the American Philosophical Society 125: 25-37.)

What could that mean?

Wheeler also described spacetime by saying “Spacetime tells mass how to move; mass tells spacetime how to bend”. Stepping back from Einstein to Newton for a moment, the Third Law states that between two masses, “For every action there is an equal and opposite reaction”.

Applying Newton’s Third Law to Wheeler’s “Mass tells spacetime how to bend”, spacetime must be exerting an equal and opposite action on the mass that bends it. Rephrased simply, spacetime and mass interact gravitationally.

To the best of our knowledge, spacetime is not known to interact electromagnetically, nor in any way other than gravitationally. All of a sudden, we have then a description of spacetime that sounds awfully like that of dark matter.

Hence, Wheeler’s “Mass without matter” description of black holes might be modified to “Mass without visible matter”? In any case, as noted in the comment above on December 20, 2017, there is no shortage of speculation that black holes are dark matter.

More fundamentally, could spacetime, dark matter, and black holes be the same reality, albeit playing different roles (thus carrying different names), other than sharing the same description?

Thank you for the reminder.

Apologies for failing to link the April article for everyone’s convenience. That was inadvertent, due in part to distraction by a notion where, stealing your words, readers might “be put off by unfamiliar ideas and terminology”.

It is good that the no-cloning theorem is not violated. On the other hand, if one is serious about black holes being governed by quantum rules, there might be a more basic worry. Namely, a suggestion that quantum reality cannot be our familiar classical physical reality (“nonphysical” lacking proper terminology).

If that fundamental concern is valid, black holes could be devoid of interiors. Even the information they hold might be nonphysical, in the above strict sense.

Short of ready availability, a rather clumsy version of the thought experiment on which the conclusion of non-classical physical quantum reality is based can be found in http://www.preposterousuniverse.com/blog/2017/10/13/mind-blowing-quantum-mechanics/.

The possibility of this nonphysical quantum reality facilitated the linking of black holes and dark matter in the Dec 20 comment.

In turn, that has led to a refinement of what “nonphysical” may mean, in the quest to understand a little more, despite Feynman’s lament, what quantum reality might be, in addition to what it might not be.

KC

I wrote about traversable wormholes here:

Here’s one way to get out of a black hole!

In ER=EPR, the entanglement between two black holes can be thought of as the black holes measuring each other. No measurement can produce predictable outcomes in the quantum world.

Even if ERs are traversible, the above stipulation means information can only be passed to an unpredictable black hole. Quantum rules forbid “designating” a second black hole as the “predictable” recipient for any sending black hole.

Hawking says the message from a black hole is scrambled. He focuses on the message. The above pays heed to the recipients of messages. In a sense, similar to the message in Hawking radiation, the recipient black holes appear “randomly scrambled”, to the sending black hole.

In both cases, the result is that no reliable information can be faithfully passed through the worm holes. Can the information paradox be considered solved?

KC

To be noted is the uncanny similarity of that description and our current understanding of dark matter.

If taken seriously, it might lend potential support to the recent argument that black holes are dark matter.