

Negative Mass An amusing thought experiment, or the Secret of the Universe? - smokinn
http://www.triplenine.org/articles/Negative_Mass.htm

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Semiapies
Oy.

 _"To settle the question, I called a well-known astronomer who had recently
published an article on gravitational lensing. After a brief explanation of
negative mass, I asked him if he had ever seen background galaxies distorted
into spokes in the absence of luminous foreground galaxies. He said he had
seen the phenomenon, but he said it was caused by "something else." I asked
him what else could cause that, but he refused to answer and abruptly ended
the conversation. So until someone can explain to me what that "something
else" might be, I consider this prediction to have been proven correct."_

That's a couple of classic psychoceramic shticks, right there. Unnamed "well-
known" scientist who provides evidence to support the hypothesis, and hinting
at a cover-up.

~~~
aphyr
I think that last line is even more telling. "I consider this prediction to
have been proven correct." Credibility: zero.

~~~
Semiapies
_And_ putting the burden of proof of explanations for this probably
nonexistent phenomenon on anyone trying to argue the point.

------
lmkg
Very interesting thought experiment, and it certainly seems to make some
exciting postdictions. However, before accepting it, I would need to see what
happens with negative _inertial_ mass. Recall that, unlike electric charges,
mass has a second role in physics beyond its interaction with one of the four
primary forces. Specifically, it's the relation between force and
acceleration. General relativity is founded on examining the connection
between gravitational mass and inertial mass. If a body has negative
gravitational mass, does that mean that it has negative inertial mass as well?
Would this mean that if you apply a force on such a body, it accelerates in
the opposite direction?

Also, regarding the astronomer that hung up: maybe he's gotten a lot of calls
from pseudo-science cranks, and the author sounded like one on the phone. I
can understand not wanting to waste your time on that.

~~~
phaedrus
He specifically answers the concern about negative inertial mass!

He proposes that to make negative mass make sense with regard to inertia, the
equation F = ma should actually have been F = |m|a.

~~~
Semiapies
He does not answer the concern, he just throws down absolute value bars to
make all inertia work the same way.

~~~
growingconcern
Actually he did answer it. You just didn't like his answer.

~~~
Semiapies
Just to explain what might be a tricky point, an equation like F = ma isn't
just pulled out of the aether. It's a representation of known and studied
behavior.

There is no known and studied behavior of objects with negative mass. There
isn't even a rationale for throwing down absolute-value bars beyond
"symmetry".

------
carterac
Reasons I am skeptical: the conclusions have extremely profound implications
for physics yet this hasn't appeared on my radar through an established
journal.

Reasons this is believable: It answers two major questions I have with the
current model.

1\. Cosmic acceleration. This has been written off as the result of "dark
energy." A total cop out, and worst of all, it violates the laws of
thermodynamics since energy is being added to the system.

2\. The concentration of positive amounts of mass during early stages of the
universe should have created a black hole.

Overall I'm still skeptical, but on the other hand, this is a more believable
theory that addresses those questions than I have heard so far. I'm very
curious if anyone else thinks it may have merit on this basis. I would also
love to know if anyone can independently validate the accuracy of the
simulations.

~~~
marze
The article says the simulations took 60 hours on a "486/DX-33". That brings
back memories. Anyone could rerun the simulations on a modern PC by writing
about 50 lines of code and 10 minutes of runtime.

While it is easy to criticize odd-ball theories, I think it is more fun to try
to think of tests that might support them or disprove them.

~~~
bcowcher
I decided to try just that (with html canvas). Its probably WAY off, but it
was fun to mash up. <http://thecowch.com/media/demo/index.html>

edit: just a disclaimer, im no genius at physics and Ive probably
misinterpreted the OP's post or made some other gross flaw in this sim.

------
Panoramix
The idea of negative|imaginary mass has been studied in more depth,
particularly in the context of general relativity.
<http://en.wikipedia.org/wiki/Exotic_matter>

------
scotty79
> I asked him if he had ever seen background galaxies distorted into spokes in
> the absence of luminous foreground galaxies. He said he had seen the
> phenomenon, but he said it was caused by "something else."

Has someone seen some picture and/or explanation of origin?

------
jeromec
My thoughts center not so much on all of the conjecture, but of the concept of
negative mass itself. The author asks _where_ it might be, but I think it
would be better to ask _when_ it might be. It's likely mass is always positive
because _time_ is always positive. We take it that all things in existence
have mass; if it doesn't have mass it doesn't exist. The concept of negative
mass would imply not only that something doesn't exist - it doesn't occur in
time - but _it_ specifically doesn't exist, and impacts the universe in the
opposite way it would with positive mass. An illustrative example would be a
tennis ball on a table. The tennis ball has positive mass, and relates to the
universe in ways we are familiar with. If we said the tennis ball's mass was
negative, then we are saying that in the universe on the table there
specifically isn't the tennis ball, and not just that it doesn't exist, but
it's missing (because we're negative) at that point and time, and the universe
is affected proportionally.

~~~
tjarratt
So you'd say that any object without mass does not exist? Perhaps you'd like
to brush up on photons and gauge bosons. The author was no more saying that an
object with negative mass is non-existent than a debt is a hole in your
wallet. Negative numbers have more meaning than subtraction.

<http://en.wikipedia.org/wiki/Massless_particle>

~~~
jeromec
Discounting relativistic mass, yes. I'm not sure what the author's specific
thoughts on that are; I was only pointing out my view, but your "debt is a
hole in the wallet" is actually similar to what I'm proposing. The key is the
object doesn't only not exist, it's _missing_. By the way, whoever upvoted my
comment above, good one. It's not easy to wrap your brain around the
implication. :)

------
sp332
Wouldn't dark matter provide an alternate explanation for "filament" structure
in the universe? The results of the Millenium Simulation seem to fit his
qualitative description, and it was run with 10 billion particles, so it's
definitely got enough resolution. <http://www.mpa-
garching.mpg.de/galform/virgo/millennium/>

~~~
CraigBuchek
I think the point is that negative mass might be an explanation for dark
matter and/or dark energy. Scientists don't really have any explanation for
what either of those are -- they're really just "fudge factors" to make the
theories fit our observations. To fully understand things, we need to figure
out why we need the fudge factors.

------
jerf
All things considered, "someone" could probably toss together a simulation to
check the results in well under a week with modern tools, and run it on a
modern processor. A modern processor could do much more finely-grained deltas.

~~~
JabavuAdams
No they couldn't. They could just simulate more bodies, but it wouldn't prove
anything.

You run a simulation with 1000 times as many bodies. Okay, it looks kind of
filamenty. What have you learned?

~~~
jerf
That the results are robust in terms of your limited simulation. Whether or
not it was clear, I was saying that the _results of the simulation_ could be
checked, not that therefore automatically he's right about his
_interpretation_ of the results.

------
drhodes
There is a section on filaments at the very bottom of this page:
<http://rst.gsfc.nasa.gov/Sect20/A1.html>

I think that's what he means by spokes.

------
shalmanese
[http://blog.figuringshitout.com/anything-you-think-is-
either...](http://blog.figuringshitout.com/anything-you-think-is-either-
unoriginal-wrong-or-both/)

I would be more convinced if he had shown how he was being unoriginal rather
than original.

------
python123
This is what one of those nerdy, but not actually smart, kids in class went on
to do. The others seem to be on HN. If you can't figure out why saying two
collections of points "look alike" doesn't mean anything, then it's no
surprise you think _Outliers_ makes a compelling argument.

