Real science pays real attention to empirical reality, and stands ready to turn on a dime
when important new information comes in. And it always remembers that learning from
experience and experiment... is a kind of game of probabilities, which those of us
who know about learning never forget.
About three days ago, I was very open-minded in principle about whether
Einstein's general theory of relativity (GR) is the ultimate truth. But in practice,
I didn't see any reason to doubt it, or to doubt the conclusion that realistic human
travel beyond the speed of light would be essentially impossible. OK, there are
wormhole solutions to GR, but I gather that these tend to be unstable and ask for
use of a kind of matter ("exotic matter" with negative mass) that we have absolutely no
idea of how to produce, whose very existence is hypothetical and a problem for all
present physical theories. For the "next big revolution" in physics, I saw
changes in all parts of physics EXCEPT GR.
But now... a major new empirical result has come in (see above).
On a HUGE scale, we have known for a decade or two that the great motions of galaxies
are grossly out of line with what would be predicted from GR, based on the mass of
what we see out there. But the hypothesis of "dark matter" seemed to solve all that.
This is where the psychology of modern science gets to be quite interesting... and
predictably pathological. We had two choices out there -- to assume a huge amount
of a new kind of matter, totally different from anything in our experience
or in today's standard model of physics electroweak theory plus quantum chromodynamics,
the twin pillars of most of physics today), or to change GR. To change
the standard model, or to change GR. Apriori, I can't see why we should have so much
confidence that the standard model is the one that has to change, and that GR is the
one which has to say the same. We don 't really know yet. The weird thing is that
the reactive political establishment of physics is usually very upset when I suggest tinkering with the tiniest detail of the standard model, to make it more consistent with GR. Usually I am "on the GR side." But the sheer mental inertia takes over...
when they have played with dark matter for all of a decade or two, it becomes instant nonquestionable dogma to many!
I am in the minority who really believes we DO have compelling reasons to question the standard model of physics as it stands today, at its core, and has provided an alternative. But in the new controversy... dark matter versus changing GR..
I am utterly agnostic and vastly entertained.
It intrigues me that MSNBC and LiveScience, in reporting the study, ASKED
the obvious question: "Ok, if we can take this experimental result at face value
even though we have a lot of checking to do), what does that tell us?"
Suddenly there is a significant possibility (30-60% probability, like) that
replacing GR with a new theory by Moffat, a theory called MOG (Modified Gravity),
is a "next big step up" for physics, much closer to reality than GR.
We shouldn't suddenly treat that as a new dogma... but we have every reason to take it seriously.
Also, all of a sudden, all those analyses of how hard it would be to do FTL travel...
may be based on the wrong theory. In MOG, the speed of light is a variable.
The basics of MOG are available on wikipedia.
People have not yet studied MOG so much as they have studied MOG, so we do not yet know. There are many interesting questions here --
1. What ARE the FTL implications if MOG happens to be true?
2. Are there problems with stability and well-definedness with MOG which may justify
some technical changes in the theory -- or which introduce novel stochastic factors?
3. Does his phi field really have exactly the form given? Does it require modifications such as those I argue we need for the "Higgs field" in electroweak theory? Or does it also couple with neutrinos or such? (Phi itself could be considered
a KIND of dark matter, a very different kind from what reactive thinkers have assumed.)
And, of course, there are the questions of whether the new experimental result will
hold up when new surveys of stars or galaxies are done. (Yet it is still possible that the dark matter hypothesis is consistent with data on one scale but not another; it would be a typical mental aberration for folks to assume that consistency on one scale "shows that the earlier result" (about another scale) "is wrong." Also, as Moni-Bidin has noted, "we might find that the dark matter is there, but is simply shaped like a giant cigar in space... though I can't quite imagine why that would be as yet."
UNLIKE MOffat's theory, these cigar alternatives are not so well motivated right
now... but we will see.
Some critics have said: "that's well and good, but where are the phions?"
Well, in my version of QFT we shouldn't expect to see phions UNLESS a specific
decay mechanism has been predicted and looked for; perhaps I need to do more google search to see whether that is the case, but I am not aware of it right now.
It would be really nice if people could remember that old idea about exploring the unknown and paying enough respect to empirical reality... not only from Solyndra..
By the way -- I mentioned wormholes here mainly because most people know about them,
and I always seem to be at risk from giving more details than people feel comfortable with. But in truth -- I was really thinking of the "Alcubierre solution" in GR,
which also requires "exotic matter." Would that kind of faster than light moving solution be possible in MOG, without negative mass matter? I don't know. It would
be interesting to find out.
Not that we should rule out the possibility of someday discovering negative mass
matter. That doesn't seem to fit very well either in today's physics or even 'the next generation," but ... m,aybe when we know more, we will be better prepared to do more justice to the possibility. Maybe.
But we have big steps to make first -- in the formulation of quantum theory,
in the realms of the standard model, and perhaps, it seems, even in the realm of gravity.