Laws Are Subject To Change As Well, Right?

[JohnR7]

Except for every time God felt like coming up with a new covenant

There are thousands of covenants in the Bible. The promises of God are conditional, if we do our part, then we can be sure that God will do His part.

 

[[serious]]

Laws are directly observable events. F=MA is directly observable and always holds true at not relativistic speeds on a non quantum scale. Laws are subject to further specification (such as the inclusion of reletivity) but are almost never thrown out. Evolution as a process is a law. We have directly observed the change in allele feqency and specization. Common decent, on the other hand, is a theory. A theory explains observed phenomina. Theories are only as good as the accuracy with which they maodel observed phenomina. Theories are occationally thrown out (geocentrism for example) but are more often simply modified to more accurately model observed results. the mechanisms of evolution are theory (they explain the phenominon of evolution) and have changed many times to include new discoveries (genetics, details of the fossil record, measurement of mutation rates, etc.)

 

[Chalnoth]

I need to read up on String Theory, and with that in mind, does String Theory make any predictions that differ from other models?

Well, I don't think that string theory, in its more general form, provides any predictions whatsoever. Just to give you an idea of why, if you consider that the most basic form of string theory is a 10-dimensional theory, with the 6 higher dimensions curled up into tight balls, so that we never see them. But there are some 10^500 different ways of compactifying, so there doesn't appear to be any prediction string theory can make here.

Now, a few very specific models provide some predictions. One is that if certain parameters are just right, we might start making miniature black holes at the LHC (Large Hadron Collider) that is set to go online next year. This would be rather exciting because we would then be able to experimentally test quantum gravity. And no, the black holes won't eat up the Earth: they'll radiate away in some obscenely tiny fraction of a second. Another possible prediction is that if the parameters are just so, we may be able to measure gravity to be different at short distances.

However, in general it isn't even necessary to use string theory to arrive at these predictions, as they are usually nothing more than the predictions that are arrived at from having extra dimensions with specific properties.

 

[Chalnoth]

Laws are directly observable events. F=MA is directly observable and always holds true at not relativistic speeds on a non quantum scale. Laws are subject to further specification (such as the inclusion of reletivity) but are almost never thrown out. Evolution as a process is a law. We have directly observed the change in allele feqency and specization. Common decent, on the other hand, is a theory. A theory explains observed phenomina. Theories are only as good as the accuracy with which they maodel observed phenomina. Theories are occationally thrown out (geocentrism for example) but are more often simply modified to more accurately model observed results. the mechanisms of evolution are theory (they explain the phenominon of evolution) and have changed many times to include new discoveries (genetics, details of the fossil record, measurement of mutation rates, etc.)

I don't think so, dantose. What is the most recently-discovered scientific law you are aware of?

 

[AV1611VET]

I'm pretty sure Newton's Law of F = MA was changed...

Oh, my! Will scientists admit anything works?

 

[Chalnoth]

Oh, my! Will scientists admit anything works?

Oh, please, don't derail this thread.

 

[Elduran]

Oh, my! Will scientists admit anything works?

You should really understand science a little more before you try to dismiss it with flippant remarks like that. If you did understand it then you'd know that knowledge gathering is a process of refining what we already know. Newton's Laws of Motion still work exceptionally well in non-quantum/low speed/low gravity situations, which is exactly what Newton had available to him when he investigated.

As it happens, those laws of motion are still very accurate under most everyday circumstances.

Which laws of motion did the bible come up with that are better than this? Oh yeah, something about an unmoving earth, right? Look how that worked out! It requires the knowledge that modern science has provided in order to interpret it correctly (either that or it was just plain wrong to begin with and fundamentalists don't want to admit it...)

 

[Dragar]

And no, the black holes won't eat up the Earth: they'll radiate away in some obscenely tiny fraction of a second.

Assuming Hawking radiation is for real, right?

Now that is a test.

 

[Chalnoth]

Assuming Hawking radiation is for real, right?

Now that is a test.

I don't think Hawking radiation necessarily requires string theory, either. It can be shown that the horizon of a black hole should act like a thermal body even with classical general relativity. A quantum theory of gravity (of which string theory is one possible candidate) just provides the mechanism that shows how this can occur.

From what I understand, then, Hawking radiation is currently expected to be just a mathematical consequence of the existence of black holes. It has not, as yet, been measured, so we can't be absolutely certain that it occurs. We mostly have strong mathematical reasons to believe it does.

 

[Mystman]

As a bit of a sidenote: I do question the wisdom of doing "yeah, this COULD obliterate the entire universe.... but if our thus far non-tested theories are correct it shouldn't happen" experiments. e.g., mini-blackholes, mini-bigbangs,etc.

I'm sure that the people doing the experimenting understand the risks better, but for the average n00b, it does seem a bit stupid.

 

[Dragar]

I don't think Hawking radiation necessarily requires string theory, either. It can be shown that the horizon of a black hole should act like a thermal body even with classical general relativity. A quantum theory of gravity (of which string theory is one possible candidate) just provides the mechanism that shows how this can occur.

From what I understand, then, Hawking radiation is currently expected to be just a mathematical consequence of the existence of black holes. It has not, as yet, been measured, so we can't be absolutely certain that it occurs. We mostly have strong mathematical reasons to believe it does.

Oh, no - I mean it would be a somewhat dramatic test of Hawking radiation. If CERN vanishes into a black hole any time soon, we'll know Hawking was a bit off in his calculations.

I really didn't mean it to have anything to do with string thoery or testing it.

 

[Psudopod]

Oh, my! Will scientists admit anything works?

You don't need a scientist to admit it - you can test it yourself. Science is good like that: don't believe something, then go out and test it. Admittedly, not everything can be tested in home lab, but this one can.

 

[[serious]]

I don't think so, dantose. What is the most recently-discovered scientific law you are aware of?

What specifically in my post do you not think?

As for the most recently discovered law, I'm not great with putting together timelines of the stuff but I'd say probably the black body laws are the most recent that I could specifically name. There have been a number of laws discovered/explicitly defined in the past century.

 

[rmwilliamsll]

as is customary in a discussion of philosophy, plato.stanford has something good to say

see:
http://plato.stanford.edu/entries/laws-of-nature/

 

[Kahalachan]

I haven't heard of any new scientific laws for something like a hundred years, so I think it's more just a holdover from a more innocent age.

Einstein and Neils Bohr came up with some more recent ones for physics.

 

[Chalnoth]

Einstein and Neils Bohr came up with some more recent ones for physics.

I'm not aware that those were ever called laws. I mean, Einstein produced the theories of special and general relativity, and described the photoelectric effect, along with doing a lot more in developing early quantum theory. Neils Bohr produced an empirical model for the atom, as I recall, and was also very active in the early years of quantum theory, but I'm not aware of any laws to his name (not that I'm all that great at the history of physics myself).

Can you remember more specifically what you're referring to?

I know that I myself don't remember anything described as a law in physics other than Newton's Laws, the Laws of Thermodynamics, and some laws by various people relating to electricity and magnetism. All were empirical statements about the nature of the universe, and I think that the more modern perspective is to be much more tentative about making statements about nature, and as such we just call these statements theories instead of laws.

 

[Kahalachan]

Energy of a photon = frequency of light x's Plank's constant is one.

 

[Chalnoth]

Energy of a photon = frequency of light x's Plank's constant is one.

Hmm, from a bit of searching around, I can't see where that's actually called a law. But it looks like blackbody radiation is sometimes called, "Planck's Law of Blackbody Radiation." Anyway, it seems like the point does stand, in that we just call these things theories or models instead of laws these days.

 

[shernren]

Just to muddy the discussion a bit, Wikipedia has a lot of material about those things you want to call theories:

http://en.wikipedia.org/wiki/Physical_law
http://en.wikipedia.org/wiki/List_of_laws_in_science
http://en.wikipedia.org/wiki/Scientific_laws_named_after_people

Particularly worthy of comment:

Several general properties of physical laws have been identified (see Davies (1992) and Feynman (1965) as noted, although each of the characterizations is not necessarily original to them). Physical laws are:

• True (a.k.a. valid). By definition, there have never been repeatable contradicting observations.
• Universal. They appear to apply everywhere in the universe. (Davies)
• Simple. They are typically expressed in terms of a single mathematical equation. (Davies)
• Absolute. Nothing in the universe appears to affect them. (Davies)
• Stable. Unchanged since first discovered (although they may have been shown to be approximations of more accurate laws—see "Laws as approximations" below),
• Eternal. they appear unchanged since the beginning of the universe (according to observations). It is thus presumed that they will remain unchanged in the future. (Davies)
• Omnipotent. Everything in the universe apparently must comply with them (according to observations). (Davies)
• Generally conservative of quantity. (Feynman)
• Often expressions of existing homogeneities (symmetries) of space and time. (Feynman)
• Typically theoretically reversible in time (if non-quantum), although time itself is irreversible. (Feynman)

Often, those who understand the mathematics and concepts well enough to understand the essence of the physical laws also feel that they possess an inherent intellectual beauty. Many scientists state that they use intuition as a guide in developing hypotheses, since laws are reflection of symmetries and there is a connection between beauty and symmetry. However, this has not always been the case; Newton himself justified his belief in the asymmetry of the universe because his laws appeared to imply it.
Physical laws are distinguished from scientific theories by their simplicity. Scientific theories are generally more complex than laws; they have many component parts, and are more likely to be changed as the body of available experimental data and analysis develops. This is because a physical law is a summary observation of strictly empirical matters, whereas a theory is a model that accounts for the observation, explains it, relates it to other observations, and makes testable predictions based upon it. Simply stated, while a law notes that something happens, a theory explains why and how something happens.