Plastic Photon said:
I am looking for controversial subjects in physics, and possibly other sciences including math.
Controversial topics are topics on which, amongst scholars, different opinions exist. However, the list you make seems not to contain many of these items. They seem to rather contain two different classes: things on which a large consensus exists that they are FALSE, and things on which a large consensus exists that they are TRUE. Now, of course, for about every topic, you can find a few people who convinced of the opposite, but then, almost every statement is a controversial statement (because you'll always find a few lunatics who claim it is different, for almost "religious" reasons).
1) Cold Fusion
2) Free energy/Perpetual motion
3) Qualifiying characteristics of a planet (What makes a planet a planet?)
4) Blackholes
5) Wormholes
6) Riemman's Hyp. (can it be proven or not?)
7) Big Bang (static universe?, hot?)
8) Evolution
9) Embryonic Stem Cell Rsrch.
1) was a joke. Apart from a few believers, cold fusion has never been demonstrated, and has no theoretical basis.
2) it is generally believed that violations of the first and second law of thermodynamics are impossible. There are good theoretical reasons to believe this, and there is no experimental indication what so ever to say the opposite.
3) How to define a word (planet) is a matter of semantics, not of science.
4) There is so much observational support for black holes that I don't think that there is much controversy left. The exact nature of a black hole can still be controversial in a way, of course, but I guess most scientists will take on the attitude that we don't know the exact nature of a black hole. We know what general relativity has to say on the subject, and all observational data correspond to what general relativity says. So black holes are "standard" physics.
5) Wormholes are probably much more controversial, yes. They are solutions to the equations of general relativity, but the controversy is probably about whether such solutions do appear in nature or not.
6) can't comment, really. It is a mathematical conjecture, no ?
7) I think that the Big Bang model, in big lines, is generally accepted. There is a *huge* amount of observations in agreement with its predictions.
8) Evolution is standard science. There's no controversy over it at all. Some details can be controversial, but there's no serious scientist who doubts the general lines of it (for instance, that birds evolved from a certain branch of dinosaurs, or that humans evolved from the great apes in the African plains).
9) This is an *ethical* controversy, not a scientific one.
Now, if I may suggest two real controversies in science, I would say:
a) dark matter and dark energy.
b) interpretational issues in quantum theory (although this does not always lead to purely scientific controversies) and related issues such as the validity of the superposition principle on large scales, locality and all that.
c) supersymmetry.
d) the possibility of "closed, timelike paths" (the GR name for time travel).
This is on the same level as wormholes (in fact, both issues are related). The solutions exist, but is it, or is it not, really a possibility in our universe ?
However, I don't know in what way these are "controversial" and not simply "open questions".
e) There ARE a lot of battles going on amongst String theorists, Loop quantum gravity people and so on... Now in as much that this is a _scientific_ discussion, and in how much this is people who lost all contact with experimental reality arguing over totally hypothetical subjects and even personal attitudes, is of course the question.
Physical science is probably not the best place to look after controversy !
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