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How to falsify evolution

Mystman

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Micaiah said:
Why? The link offers only the statement.

why 1: it is found experimentally
why 2: it has something to do with a fast moving train, a light bulb, and 2 observers.. one in the train, and one standing still. (I've grasped the concept once... but then forgot it :doh:
 
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Oliver

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Why? Well, it is the central idea of Einstein's relativity. A very quick summary would be that for objects moving at high speed, you get strange effects which are not predicted by Newton's laws of motion (for example nothing can travel faster than the speed of light, time seems to be relative, etc.). And thses behaviours have been confirmed by ewperiments.

You'll find more details here:
http://www.astronomynotes.com/relativity/s2.htm
 
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Micaiah

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Out with the old text book "Fundamentals of Physics" by Halliday and Resnick.

The main issue seems to be with the formulation F=ma when applied to things travelling at the speed of light. The problem here is that at the speed of light, sub atomic particles change their mass. The above formulation assumes a constant mass. Euler apparently wrote the above formulation and it holds for most of the situations we are familiar with including from what I've seen most space travel calculations.

Newton's original formulation of the second law was far more careful and was written in terms of the time rate of change of momentum. It went like this:

The time rate of change of momentum of a body is proportional to the resultant force acting on the body and is in the direction of that force.

ie. dP/dt = F

Momentum is the poduct of mass and velocity

P=mv

Hence dP/dt = d(mv)/dt

Note that the mass of the body is within the derivative. The mass of subatomic particles change according to the following:

m=mo/(1-v^2/c^2)^(1/2)

were mo is the initial mass of the particle, v the particle speed, and c the speed of light.

Using this formulation for mass, Newton's second law is still valid for speeds over the speed of light since P=mv.

An interesting piece of trivia to correct the wrong notion that Newtons laws of motion were debunked by Einstein.
 
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Oliver

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An interesting piece of trivia to correct the wrong notion that Newtons laws of motion were debunked by Einstein

Since Einstein is the one who introduced this correcting factor, the notion that Newton's law were corrected (rather than debunked) by Einstein is indeed correct.

This redefinition of the mass is only a way to keep a similar form for this law while still introducing relativity. This doesn't change the fact that using Newton's laws without Einstein's correction, one could not explain the results of the experiments alluded to in the linked article.
 
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Silent Bob

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Micaiah said:
An interesting piece of trivia to correct the wrong notion that Newtons laws of motion were debunked by Einstein.

[URL="http://jolomo.net/solarsystem/1936.08.html" said:
Link[/URL]]So Mercury's orbit gave the first and oldest proof of the correctness of Einstein's new modification of the law of gravity. Curiously, Newton's law is exact on Earth -- but inapplicable on Mercury. Mercury is Einstein's world -- a world so close to the immense mass of the Sun that the laws of Nature we know do not apply.

[snip]

On Mercury, basic laws we know would need modification. The power of two magnets would not be the same, the attraction between two electric charges changed. They would not obey the laws of normal space, for the Sun has changed those laws.

Newton's laws of motion is not the only thing that changed by Einstein, our entire view of space and time changed forever. So Newton IS wrong Einstein IS right we know that from experiments and data. Now back to the thread.
 
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GoSeminoles!

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Mocca said:
I'm annoyed by the claim that evolution is unfalsifiable. IT IS! Anyone wanna list possible falsification of evolution?

I'll name one: If ERVs were found to be shared between two organisms with distant ancestry, and not found in other descendants of said distant ancestor.

Creationists might find this thread as a useful resource. Hint, hint.

I disagree. The fact of evolution cannot be falsified. One cannot falsify a verified observation; the facts are what they are.

I doubt that even the modern theory of evolution by natural selection with common descent can be falsified at this point. Don't get me wrong -- in principle the theory generates abundant testable and falsifiable predictions. My point is that natural selection has been so thoroughly successful in its tests, it is clearly a major driving force behind evolution. No future discoveries can alter the fact that natural selection has so much predictive power.

Instead, the worst case scenario for the modern ToE is that it will be found to be incomplete (heck, we already know this). I am confident other fascinating dimensions to the evolutionary process will be discovered in the future, but none of those can negate the fact that natural selection is a real and significant force.
 
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GoSeminoles!

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Silent Bob said:
Newton's laws of motion is not the only thing that changed by Einstein, our entire view of space and time changed forever. So Newton IS wrong Einstein IS right we know that from experiments and data. Now back to the thread.

Isn't incomplete a better way to describe Newton than wrong? Cleary, Newton is wrong at high speeds/masses, but for the range of values it was intended to use, it is still correct, no?
 
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Mocca

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GoSeminoles! said:
I disagree. The fact of evolution cannot be falsified. One cannot falsify a verified observation; the facts are what they are.

I doubt that even the modern theory of evolution by natural selection with common descent can be falsified at this point. Don't get me wrong -- in principle the theory generates abundant testable and falsifiable predictions. My point is that natural selection has been so thoroughly successful in its tests, it is clearly a major driving force behind evolution. No future discoveries can alter the fact that natural selection has so much predictive power.

Instead, the worst case scenario for the modern ToE is that it will be found to be incomplete (heck, we already know this). I am confident other fascinating dimensions to the evolutionary process will be discovered in the future, but none of those can negate the fact that natural selection is a real and significant force.

Ah, yes, I meant the theory, should have specified. And I agree that it's probably not gonna get falsified. But my point is, the Theory of Evolution is still falsifiable... hypothetically.
 
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Micaiah

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Oliver said:


Since Einstein is the one who introduced this correcting factor, the notion that Newton's law were corrected (rather than debunked) by Einstein is indeed correct.

This redefinition of the mass is only a way to keep a similar form for this law while still introducing relativity. This doesn't change the fact that using Newton's laws without Einstein's correction, one could not explain the results of the experiments alluded to in the linked article.

You misunderstood the post. Read it again. The forumulation provided by Newton discussed above was not debunked or corrected.
 
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Micaiah

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Silent Bob said:
Newton's laws of motion is not the only thing that changed by Einstein, our entire view of space and time changed forever. So Newton IS wrong Einstein IS right we know that from experiments and data. Now back to the thread.

I discussed one of Newtons laws of motion above. Space and time to my knowledge do not change those laws. If you would like to demonstrate how they do, then start another thread.
 
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KerrMetric

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Micaiah said:
Out with the old text book "Fundamentals of Physics" by Halliday and Resnick.

The main issue seems to be with the formulation F=ma when applied to things travelling at the speed of light. The problem here is that at the speed of light, sub atomic particles change their mass. The above formulation assumes a constant mass. Euler apparently wrote the above formulation and it holds for most of the situations we are familiar with including from what I've seen most space travel calculations.

Newton's original formulation of the second law was far more careful and was written in terms of the time rate of change of momentum. It went like this:

The time rate of change of momentum of a body is proportional to the resultant force acting on the body and is in the direction of that force.

ie. dP/dt = F

Momentum is the poduct of mass and velocity

P=mv

Hence dP/dt = d(mv)/dt

Note that the mass of the body is within the derivative. The mass of subatomic particles change according to the following:

m=mo/(1-v^2/c^2)^(1/2)

were mo is the initial mass of the particle, v the particle speed, and c the speed of light.

Using this formulation for mass, Newton's second law is still valid for speeds over the speed of light since P=mv.

An interesting piece of trivia to correct the wrong notion that Newtons laws of motion were debunked by Einstein.



NOTE TO ALL:


MASS does not change with velocity. This is typical old text book spiel that confuses people. Any modern relativity text never says that -or shouldn't in case you find an exception.

Mass is fixed. What changes is something that used to be called relativistic mass - which is a measure of the total energy of a body divided by c^2. But the actual mass, often termed the rest mass, does not change.

In the formula

m=mo/(1-v^2/c^2)^(1/2)

mo is the rest mass which is the mass and does NOT change. The m is not a mass but the so called relativistic mass which is an energy/c^2 mass equivalent.
 
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Micaiah

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KerrMetric said:
NOTE TO ALL:


MASS does not change with velocity. This is typical old text book spiel that confuses people. Any modern relativity text never says that -or shouldn't in case you find an exception.

Mass is fixed. What changes is something that used to be called relativistic mass - which is a measure of the total energy of a body divided by c^2. But the actual mass, often termed the rest mass, does not change.

In the formula

m=mo/(1-v^2/c^2)^(1/2)

mo is the rest mass which is the mass and does NOT change. The m is not a mass but the so called relativistic mass which is an energy/c^2 mass equivalent.

Suggest we start a new thread if you wish to take this further. Newton's formulation is good for situations where mass varies, be it relativistic or real.
 
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Apos

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The train/lightbulb issue is this:

Imagine a lightbulb on a train, set between two people at opposite ends of the train. The light turns on. Who does the light hit first?

The answer depends on your frame of reference. Light travels at a constant speed no matter what: unlike a ball thrown on the train, it isn't affected by the movement of the train: it still moves at it's same constant speed. So if you are on the train, the light travels the same distance and so reaches the two people at the same time.

But if you are off the train, watching it go past, the light actually reaches the back end of the train first. In the time it takes to travel there, the back of the train has moved towards the oncoming light, and the front has moved away.

Another way to think about it is a beam of light bouncing back and forth between two perfect mirrors, one on top, one on bottom. If you are moving in the same frame of reference as the mirrors, the beams travel straight up and down, bouncing between the mirrors. But if you are watching the moving mirrors travel by you , the path of the light is not straight up and down: it's diagonal. Which is a longer distance to travel than straight up and down. And yet, the light is somehow both traveling at the same speed and yet covering more distance.
 
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KerrMetric

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Micaiah said:
Suggest we start a new thread if you wish to take this further. Newton's formulation is good for situations where mass varies, be it relativistic or real.

No need to.

You were sort of confusing to issues I think. You were correct in saying that F=ma is better represented as F=dp/dt. But the variable mass possible there (like in those conveyor belt problems in high shool physics) has nothing to do with the idea of relativistic mass and the oft said mass changing with velocity.

As I said - the mass really doesn't change. It is the time component of the momentum 4 -vector that changes under a Lorentz transformation to get the "relativistic mass". But this component in the rest frame is just the rest mass and that never changes. The puzzle for people is that the 4-vector as a whole is conserved and not the individual components when transforming to another frame.
 
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Jianyi Zhang

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Mocca said:
I'm annoyed by the claim that evolution is unfalsifiable. IT IS! Anyone wanna list possible falsification of evolution?

There are some ways to falsify evolution, for example, fossil sequence. However, I can not think ways to falsify theories regarding mechanisms of evolution, such as speciation by NS, geographical isolation, genetic drifting?
 
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Jianyi Zhang

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shinbits said:
That wouldn't falsify evolution. An evolution would just claim that the right fossils just haven't been found yet.
I did not mean fossils falsify evolution, what I mean is that evolution could be falsified by fossil sequence, it is not falsified because of the sequence.
What I really say is that those popular mechanism not falsified as nobody can tell what animals evolved or will evolve by any specific mechanism. By the Popperian rule, those theories are pseudo-scientific ones.
 
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