# Controversial topics in physics

1. ### Plastic Photon

166
I am looking for controversial subjects in physics, and possibly other sciences including math. There is a paper due at the end of my semester of english/composition and I must write on any controversial subject (so long as two sides to the issue exist, which is not very specific). ie (iraq war, abortion, etc)

SO far I have come up with:
Cold Fusion
Free energy/Perpetual motion
Qualifiying characteristics of a planet (What makes a planet a planet?)
Blackholes
Wormholes
Riemman's Hyp. (can it be proven or not?)
Big Bang (static universe?, hot?)
Evolution
Embryonic Stem Cell Rsrch.

Are there any others left?

2. ### arildno

12,015
Evolution is not a subject of controversy among scientists.
Neither are the possibility of perpetual motion machines a subject of controversy.

3. ### uranium138

0
Embryonic Stem Cell Rsrch. and Qualifiying characteristics of a planet (What makes a planet a planet?) r good ones
but i don't think black holes, Big Bang (static universe?, hot?) are controversy

Last edited by a moderator: Feb 2, 2006
4. ### rbj

Variable Speed of Light (a.k.a. "VSL")

Varying G or varying any other dimensionful "constant".

even though in investigating whether or not the Fine-structure "constant" ($\alpha$) has varied or not is not, in and of itself controversial, there might be some controversy if someone claims that it has certainly changed over time. the jury is still out on that.

some physicists have claimed that the speed of gravity is faster than the speed of light (which contradicts General Relativity). so that is controversial.

some people have claimed that a concept called "Gravitoelectromagnetism" (a concept that in some circumstances, gravitational fields from moving masses can have effects that are analogous to electromagnetic effects of moving charges) can conceptually be used to create an "anti-gravity" device (making other physicists blush).

the "ekpyrotic universe" is an alternative cosmology that might be controversial.

string theory has some controversy since i don't believe it has yet to be shown to be "falsifiable". if it not falsifiable, there are some physicists who will legitimately ask "who should give a damn?".

any of the hard-core experts here are welcome to add or subtract to the above list.

Last edited: Feb 3, 2006
5. ### Kazza_765

164
I may be completely wrong, so feel free to ignore me if you wish, but if your english composition is anything similar to what I had to do in highschool then some of these subjects aren't going to be very usefull. While it may be interesting to discuss whether the fine structure constant has changed, or Riemmans hypothesis can be proved, it probably wont be the sort of discussion they are after.

These sorts of assignments are usually to test your powers of persuasion and control of language. Discussing the fine structure constant or the feasability of cold fusion would require a lot of technical information, and you are largely dealing with facts, which aren't discussed with emotive language as easily as ethical/moral issues hence why people usually write these on abortion/drugs/racism etc.

So i suppose in my opinion, the best ones to write on would be Evolution v. ID (but like aldrino said, there is no controversy among scientists over this), stem cell research, the characteristics of a planet, climate change/global warming (and what to do about it), perhaps something to do with consciousness (whether we are really conscious, what makes us conscious etc.), hurricane katrina (from an engineering perspective maybe?), oh, and perhaps on race targeted medicine (http://www.racesci.org/in_media/genetic_find.htm, there's been quite a bit said about this recently).

6. ### Mk

Also, if you choose to write about Evolution vs. Creationism, see "Evolution in Action" from January's Science. I have the article in ebook if you want it, PM me.

7. ### vanesch

6,236
Staff Emeritus
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) 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 !

Last edited: Feb 3, 2006
8. ### ZapperZ

29,757
Staff Emeritus
vanesch,

Of the many, many, many posts you have done, I'd say this is one of my most favorite!!! :)

I totally agree that these are only "perceived controversies", in that experts in the field all mostly agree. It is only among the general public is there such perceived controversies because they still see different experts debating the issue, but they don't realize that these debates are on the DETAILS.

Physicists, as a community, has a very rigid standard to when something is categorized as "accepted" or "known". So we tend to simply say "we still don't know about so-and-so". But most people take that to mean we know nothing about that so-and-so. This is wrong. What most people accept to be "true", and what most people think they know, is considered to not be sufficient as valid in physics.

I would also add another actual controversy in physics to add to your list - the actual mechanism of high-Tc superconductivity. Ask 10 different physicists in this field, and you're likely to get 10 different answers. Why? Because it is still a developing, research-front field. We're still learning and discovering various phenomena surrounding this class of material, and new physics continue to be discovered and evolved. This is typical of a research-front field in physics, and in science in general.

Zz.

9. ### Plastic Photon

166
This is information is what I was seeking, thank you.

Kazza_765, as far as your past papers have gone, as far as I understand the criteria for the paper, it is not meant to be persuasive, but informative. This is what she is saying at the moment, though I think I will present a research topic prior to the due date in order to make sure what I am doing is correct and appropriate. Thank you though.

10. ### nbo10

415
I'd second the motion on high-Tc superconductivity, only because I have first hand expereince.

Last edited: Feb 4, 2006
11. ### krab

905
Some of the previous comments relate to the forefront of physics research. There's no controversy there, just different people chasing down different hypotheses. They would meet together periodically or read each other's papers, and amicably discuss their results. Your best bet is to write about something like cold fusion. That's where there is real controversy between people who claim they have a certain result and others who claimm they re-do the same experiments and get a different result.

12. ### vanesch

6,236
Staff Emeritus
:!!)

Right. There must be several items in condensed matter physics that must be "controversial" ; I'm not very knowledgeable about them, though.

13. ### vanesch

6,236
Staff Emeritus
Yes, that was more or less my conclusion, and I understand, also ZapperZ's point of view: they are more "open questions" and people working on different *potential* explanations.

To me, a real controversy is rather where you ask 1000 experts in the field, and 300 are _convinced_ that "A" is the correct statement, while 700 others are _convinced_ that "A" is bull, but that "B" is the correct answer.

When we find 10 different groups, that say "A1 looks plausible to me, but then, I'm not sure" ... "A10 looks plausible to me, but then, I'm not sure", I'd classify it as an OPEN QUESTION, as you suggest, with different people persuiing different approaches in an attempt to solve the issue.

When we find, on our 1000 experts, only 3 that think that "A" is convincingly right, and 997 think that "A" is bull, then I don't call that a controversy either (but just 3 fringe wackos who got per accident the title "expert" )

I think that that belongs to the last category :rofl:

A good read on the subject is "Yes Sir, we have no neutrons!"

14. ### bhornbuckle75

11
Make sure to make the definition of Free Energy and Perpetual Motion exact if you use this as an Idea. Perpetual Motion probably does defy Thermodynamic Laws, however the definition of this term is generally used in a closed system where new energy can not be introduced. Free Energy however is a term which is a little harder to categorically place. A "Free Energy" device could simply be a device in an open system which continually gets new energy input and therefore always has a supply of "free" energy. Actually a literal use of the term "Perpetual Motion" could also refer to such a state. For instance a waterwheel in a fast moving river will have motion which is "perpetual" (as long as the river keeps flowing that is) and could also be considered to take advantage of "free" energy. This, however would be a device which would rely on an open system rather than a closed one. An example of a perpetual motion device that works on a closed system (which is the general use of the term) would be a mobile or turning wheel which by the clever application of gears or weights, or sometimes even magnets, often arranged a dizzying, and often unintentionally artful design which by way of its complexity can trick the mind of people unfamiliar with scientific laws into believing that somehow by the nature of its own machinations it will continue to spin or turn of its own accord without the need of additional energy perpetually. Of course what does "perpetual" mean? It may be that nothing can truly be called "perpetual" due to entropy which will eventually break apart all ordered systems in the universe. A general rule however is to view the term as meaning anything that is functionally perpetual. For instance as long as it is reasonable to assume that the "perpetual motion" machine will continue to work at least until its parts wear out then its fairly safe to say it is perpetual. I have also heard the term used to describe something which will function for at least as long as the lifespan of the person using it. Anyway, basically all I am saying is that when you discuss either "free energy" or "perpetual motion" it is important that you define the meanings within your argument. I have noticed that most any of the controversial statements, (at least the ones that have enough merit to mention) regarding these concepts often come from one or both sides being vague in their definition of the meanings of these ideas (usually as I stated before, involving misunderstandings about open and closed systems).