
Are Black Holes Actually Dark Energy Stars? - starbugs
http://nautil.us/blog/are-black-holes-actually-dark-energy-stars
======
chc
I've seen a couple of articles about this guy recently and they both struck me
as weirdly credulous given the apparently complete lack of evidence supporting
his theory and the fact that approximately no other scientists seem to find it
credible.

~~~
joe-collins
At least at the pop-science level, his ideas connect a lot of dots. He'd
neatly resolve the weirdness and mystery of black holes, their jets, their
information paradox, and dark energy. It feels good.

Whether or not any of it makes a lick of sense once you start actually
crunching numbers is another question. The lack of interest from other
scientists leaves me skeptical (even if I'm silently enamored of the neatness
myself).

~~~
Semiapies
Yep. I've been hearing mentions of this guy's theories from pop science
publications for years even though, as the article says, "The idea has found
no support in the astrophysical community—over the last decade, Chapline’s
papers on this topic have garnered only single-digit citations."

The pop science press is depressingly bad.

~~~
philipov
"Dark Energy Star" is pure marketing speak, and the pop science press loves
sexy terms like that, whereas to serious physicists a hyphy phrase like that
is going to throw all sorts of red flags, the same way an engineer would be
appalled by someone boasting about Chaos Engineering. It's usually referred to
as the Cosmological Constant instead.

------
hinkley
We have people like string theorists thinking about higher dimensions in
space.

It occurred to me the other day when the dark matter article hit the front
page that our equation for gravity works with three dimensions but those
dimensions are uniform. I can turn an object with very little effort
(literally without doing work) and it’s the same size from our perspective.

How would it work if matter has more dimensions that aren’t proportional, or
if space is curved in higher dimensions and the differences are in the noise
floor here on earth and in orbit?

~~~
klodolph
> I can turn an object with very little effort (literally without doing work)
> and it’s the same size from our perspective.

I can't reproduce your experiment... I tried turning a piece of paper. At
first it looked, say, about as large as a cantaloupe, but when I turned it got
smaller and smaller until it practically disappeared, and it becomes very
tiny... basically nothing more than a thin line in space. At certain angles I
can barely see it at all. What is going on?

~~~
whatshisface
The distance between any two ink dots remained constant as you rotated the
paper, which is what you would expect when the metric is x^2+y^2+z^2. If the
"dimensions were not uniform," then the same transformation may alter the
distances. Perhaps the parent is on their way to discovering relativity.

------
russdill
This seems to try and make a parallel between neutron stars and his proposal
of a "dark energy star". This uber-dense matter would stop matter from
collapsing enough to form an event horizon.

But there is a serious problem with this. If you measure the density of a
black hole by using it's even horizon you'll find that the mass and event
horizon do not scale together. For instance, calculated in this way, a
galactic mass black hole has a density of only 200kg/m³.

~~~
pmalynin
It actually is true thought, that some supermassive blackholes have a density
thats pretty close to that of water, and their event horizons are very very
gentle.

~~~
m4x
I think this is only the case if you consider the mass density to be uniform
within the event horizon, which isn't true.

~~~
russdill
Right, but I don't know how else to interpret what he's claiming. Singularity
or no singularity, if there's an event horizon, there's a black hole.

------
lottin
"The fabric of space-time" — I hear this a lot, but what does it mean? Does it
mean that space and time are a "fabric"? What is such a fabric made of? The
idea that space and time are actual objects, instead of intellectual
constructs, has always struck me as wrong. (I'm not a physicist.)

~~~
philipov
It's usually referred to as a fabric because in general relativity, spacetime
is dynamic, as if it were on a fabric that could stretch and contract in
response to the density of matter occupying it. This is where the rubber-sheet
analogy comes from.

As for what it is made of, that is one of the great open questions in
theoretical physics right now, but also possibly where the analogy breaks
down. Because of Lorentz Invariance (light travels at the same speed in all
reference frames), it is hard to suppose that there is such a thing as "atoms
of spacetime" from which it is made. However, because our world is
cosmological and the big bang does actually pick out a preferred reference
frame, Lorentz Invarience has to be approximate in some way.

Because of cosmology and the breakdown of reductionism at plank scales, it
seems that the notion of spacetime itself is approximate and needs to be
replaced with something else. Some people are trying to derive spacetime from
purely quantum mechanical notions, while other people are trying to find dual
systems where spacetime and quantum mechanics emerge hand-in-hand. The two
approaches I'm familiar involve either holography or purely geometric and
combinatorial ideas where the principles of general relativity and quantum
mechanics are outputs rather than assumptions.

[https://www.youtube.com/watch?v=WECVq2YBduY&t=0s&index=9&lis...](https://www.youtube.com/watch?v=WECVq2YBduY&t=0s&index=9&list=PLOchmQOEwXhEIAnI-
pyHQlrCnEhmxGnQD)

~~~
dsnuh
Thanks for linking to the video, it was the most informative handling of the
subject I have seen.

After watching, I have a question, please forgive if it is ridiculous or
displays some fundamental problem with my layman's understanding of the
subject.

If time becomes space-like, and space becomes time-like, can we think of black
holes as "time stars"? Would every black hole within our observable universe
contain information from all light cones within the observable universe? In
other words, would different black holes contain different information?

Does my question make sense?

~~~
codethief
I'm afraid I don't have the time to watch the entire video but, being a
physicist, I can still try to answer your questions. Currently, however, your
question

> If time becomes space-like, and space becomes time-like, can we think of
> black holes as "time stars"?

doesn't make much sense to me. Time does not become spacelike nor does space
become timelike. In General Relativity, time and space are not individually
defined in an observer-independent fashion in the first place. The terms we
use instead are "timelike directions" and "spacelike directions" as well as
timelike / spacelike hypersurfaces because they are defined in such a way that
all observers will agree on whether a direction / hypersurface is timelike /
spacelike. So now that we've replaced the terms "time" and "space" with
"timelike" and "spacelike", I hope you'll see that your question is not
exactly well-defined.

But maybe I'm misunderstanding you, so please feel free to elaborate on your
questions. (Or to point me to an explanation from the video in case you're
referring to one.)

As for your second question:

> Would every black hole within our observable universe contain information
> from all light cones within the observable universe? In other words, would
> different black holes contain different information?

I'm afraid I can't follow this question, either. Would you mind rephrasing it?
My initial impression is that you might have a wrong idea of what a lightclone
is.

~~~
dsnuh
I just realized I was replying to the wrong parent comment! So sorry. I was
talking about a PBS Space Time episode on YouTube I saw in (or came across
via) a different comment.

[https://youtu.be/KePNhUJ2reI](https://youtu.be/KePNhUJ2reI)

~~~
codethief
No worries, I hadn't watched the video yet, anyway. :) So feel free to
rephrase your questions if you like!

~~~
dsnuh
My questions were based in the video I linked above, which it sounds like may
be incorrect in the way it presents the topic?

~~~
codethief
Judging from the few minutes I watched, it is at least not very precise, yes.

What they mean when saying that "time and space switch roles inside a black
hole" is that in standard Schwarzschild coordinates, the direction given by
the time coordinate becomes spacelike at the event horizon and, likewise, the
radial coordinate becomes timelike. This statement is specific to
Schwarzschild coordinates, though, or, more generally, any coordinate system
that is singular/ill-defined at the event horizon. There are coordinate
systems, however, that don't exhibit this pathological behavior at the horizon
and, there, no switching occurs.

------
clubm8
I find the idea of a photo of a black hole more interesting than this dark
energy star. It didn't seem to be mentioned in the article: when will this
"Event Horizon Telescope" have enough data to show us an event horizon?

~~~
codethief
From their blog[1]:

> As the EHT team begins to analyze the 2017 data on Sgr A* and M 87 over the
> coming months, preliminary images will begin to emerge, and the searches for
> the signatures of orbiting material around the black holes will be
> conducted. It is the most exciting time of the project.

[1] [https://eventhorizontelescope.org/blog/eht-status-update-
may...](https://eventhorizontelescope.org/blog/eht-status-update-may-1-2018)

------
macawfish
The thing is, dark energy is only dark because it doesn't interact
electromagnetically, whereas black holes are dark because the light gets
trapped. So these are very different concepts.

I think it's fair to say black holes are a kind of "star", but the concept of
dark energy and dark matter are something else.

~~~
chriswarbo
> dark energy is only dark because it doesn't interact electromagnetically

That's certainly the case for dark _matter_. After decades of work we still
don't know what it is, which has given the word "dark" the additional meaning
of 'unknown'.

When it comes to dark _energy_ , I think it mostly implies this second
meaning.

------
scythe
The big giant glaring hole in his theory is that the total mass of all the
black holes in the Universe is _WAY_ less than the amount of dark energy. It's
like claiming that the Pacific Ocean was filled in by the Sacramento River.
That's why scientists aren't taking it seriously.

------
hinkley
I managed to confuse myself into a Zeno’s paradox situation with how black
holes grow.

This is really exotic space. Time dialation immediately outside of the event
horizon would make any matter fall so slow that it would take millions of
years of time for an observer to see that material cross the horizon.

~~~
Chabs
Outside observers never see the material cross the horizon, ever. That's why
it's called a horizon, you'll never reach it (from the pov of an outside
observer).

Growth-wise, you have to keep in mind that the black hole doesn't grow when
matter crosses the horizon, but when the matter gets close enough to the
horizon that mass of black hole + mass of new matter creates a blackhole of a
larger radius that encompasses that matter.

~~~
takk309
Would this be one way that information would not be destroyed, at least from
the reference frame of the outside observer?

~~~
0898
Question if you don't mind. This "information being destroyed" thing. What do
they mean by information? Isn't information a human construct? How is the
universe supposed to know what information is?

~~~
knodi123
A fun way to imagine it is with Maxwell's Demon.

[https://en.wikipedia.org/wiki/Maxwell%27s_demon](https://en.wikipedia.org/wiki/Maxwell%27s_demon)

That is an example of one way in which information can be exchanged for work.

~~~
smogcutter
This is me being dense, but I don't see the connection to parent's question.
Is it that the demon uses information (the speed of the particles?) to perform
work (decrease entropy)? But also not really, bc that would violate the 2nd
law of thermodynamics? I understood parent's question to be what the heck does
"information" mean in this context to begin with. My question too, because I'm
pretty sure I've got the wrong answer myself.

~~~
Chabs
Information as actual physical property (as opposed to a human construct) is
basically the only way we found to solve Maxwell's demon seemingly reducing
entropy.

Specifically, the entropy within the box gets converted into information
inside the demon's "head", which eventually gets radiated away as entropy
outside the box. This way, the box's entropy falls, but the entropy of
universe as a whole is raised (or at least maintained).

------
stupidcar
If the EHT analysis of Sagittarius A* supported this theory, that would surely
it would have already leaked? It seems like it would be simply too incredible
not to start circulating amongst researchers and then get out into the wider
world.

------
Trombone12
A article about "alternative" black holes without the word LIGO in it? Yeah,
I'm gonna have to stop you right there and ask you to sell that snek oil
somewhere else.

------
laretluval
Found an interesting technical summary/critique of these ideas
[https://motls.blogspot.com/2005/03/chapline-black-holes-
dont...](https://motls.blogspot.com/2005/03/chapline-black-holes-dont-
exist.html)

~~~
qubex
Pretty savage...

~~~
21
This guy doesn't have all the screws properly tightened. Just saying...

------
PerryCox
How likely is this to be the case over Black Holes?

~~~
princekolt
No one knows for sure. However it's good to have alternative models to look
into if the observational data you eventually get (in this case from the EHT)
doesn't match precisely with the mainstream model.

------
zoggenhoff
What is dark energy?

~~~
sulam
When you sum up all the red shifts of a large piles of galaxies they are
receding from us at speeds faster than can easily be explained using the
Hubble model. One theory for this is a repulsive energy of a form we have not
yet observed, dubbed "dark energy", which is purported to be causing
accelerating expansion of the universe since the Big Bang. More here:

[https://en.wikipedia.org/wiki/Dark_energy](https://en.wikipedia.org/wiki/Dark_energy)

------
Sarki
On another note a theory which seems to fit particularly well is called Janus.
The concept lies in the existence of a twin universe (ours being matter based
the twin being antimatter based) merged together where the black holes are
basically where the antimatter is concentrated and thus repulses all the
matter hence this seemingly void. This is a succint summary but I hope it
makes sense to the more knowledgeable readers of HN.

~~~
Trombone12
That makes no sense, black holes are like super much the opposite of a void.
Further, repulsion is precisely the opposite of gravity.

~~~
Sarki
Actually, as far as I get it, black holes just don't exist: it's a journalist
term coined for a mathematical concept. In short a black hole is how we call
the possible existence of a place in the universe where there is no time nor
energy, but it's no more than a mathematical possibility in the end as these
are common variables in astrophysics.

~~~
chriswarbo
Black holes exist, in the sense that we have observed several phenomena that
can be easily explained by the presence of a black hole, but which couldn't be
explained otherwise. For example the orbits of stars around Sagittarius A* (
[https://en.wikipedia.org/wiki/Sagittarius_A*](https://en.wikipedia.org/wiki/Sagittarius_A*)
) and the X-ray emmission of Cygnus X-1 (
[https://en.wikipedia.org/wiki/Cygnus_X-1](https://en.wikipedia.org/wiki/Cygnus_X-1)
).

> In short a black hole is how we call the possible existence of a place in
> the universe where there is no time nor energy

I don't know where you got this idea, but black holes don't have "no time" and
they contain _lots_ of energy (often several stars' worth).

Keep in mind that time is relative, so when talking about extreme situations
like black holes it's important to keep track of what we're talking _relative
to_. In particular, if an astronaut left a space ship, approached a black
hole, passed beyond the event horizon and carried on going, that astronaut
wouldn't really notice: if they looked forwards into the black hole they'd
just see normal looking space, if they looked backwards they'd see their ship
just as if they'd not entered the black hole. Relative to the astronaut, space
and time appear completely normal; hence it doesn't make sense to talk about
black holes having "no time".

Things would look different relative to the ship: the image of the astronaut
they see would redshift as it approached the event horizon, and would also
slow down until it came to a stop when at the horizon.

Note that this ignores tidal forces, which can be large around small black
holes (the astronaut would certainly notice if their body were torn apart!).
For large black holes like Sagittarius A* the tidal forces at the event
horizon should be small enough to ignore.

~~~
Sarki
Thanks for the clarification, perhaps I was misleading, the point being that
black holes have been deduced by mathematical interpretation, not observation
of a phenomenon and today as per your own example we're still trying to find
proof of their existence.

On the other hand, based on my understanding of the Janus model as I said in
my first comment, the location of the seemingly void places are actually
explained by the concentration of antimatter, which repulses matter through
gravity. A possibly wrong summary of what I'm visibly struggling to
communicate: This model explains how on the same way matter concentration
attracts matter and rejects anti-matter, antimatter concentration attract
antimatter and rejects matter.

