about Bob's article on absolute or relative time

Memento Mori

New member
Hey Johnny,

Something's about Relativity has been bugging me involving relative velocities.

If you have two space ships moving toward one another at .5c. Then to each other they would appear to be traveling at 1c which is impossible. Explanation?
 

Lighthouse

The Dark Knight
Gold Subscriber
Hall of Fame
Hey Johnny,

Something's about Relativity has been bugging me involving relative velocities.

If you have two space ships moving toward one another at .5c. Then to each other they would appear to be traveling at 1c which is impossible. Explanation?
:shut:
 

Memento Mori

New member

That's right LH. I don't have all the answers! It's stunning, isn't it?

Do you have an explanation?

Also, that whole muon argument you seem to have missed. Do you have an explanation for that? (Around page 26 and 27. I'm interested to see what explanation you have. And if you do have one with all the math working out, I might just be willing to accept your theory as correct!)
 

Johnny

New member
Hey Johnny,

Something's about Relativity has been bugging me involving relative velocities.

If you have two space ships moving toward one another at .5c. Then to each other they would appear to be traveling at 1c which is impossible. Explanation?
When you sum velocities like that, you are actually only estimating relative velocities via Galilean mechanics. This works fine and well for everyday objects, but not for objects approaching the speed of light.

The actual formula for summing velocity vectors is:

w = (u + v) / [1 + (v/c)(u/c)]

where u = velocity 1; v = velocity 2; w = relative velocity

The reason this is the case is because the clocks and rulers aboard each ship are measuring time and length differently than a stationary observer would. Thus, they will measure each other's relative velocity differently (velocity being unit distance / unit time). As you can see by the equation, the relative velocities can approach c, but can never actually reach c.
 

Memento Mori

New member
When you sum velocities like that, you are actually only estimating relative velocities via Galilean mechanics. This works fine and well for everyday objects, but not for objects approaching the speed of light.

The actual formula for summing velocity vectors is:

w = (u + v) / [1 + (v/c)(u/c)]

where u = velocity 1; v = velocity 2; w = relative velocity

The reason this is the case is because the clocks and rulers aboard each ship are measuring time and length differently than a stationary observer would. Thus, they will measure each other's relative velocity differently (velocity being unit distance / unit time). As you can see by the equation, the relative velocities can approach c, but can never actually reach c.

Thank you very much! We only got to the Lorentz Factor in my Physics class. And that question has been bugging me for a while.

So, to the other, they seem to travel at .8c.
 
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Clete

Truth Smacker
Silver Subscriber
But as to whether or not reality violates the Laws of Thought, I don't know. I'd like your input on the quantum eraser experiment.
First, I'll say that such experiments have always fascinated the crap out of me. Literally ever since I was a child, such things have just blown my mind. Indeed, it was exactly that sort of experiment that made me think that I wanted to be a physicist all through high school. It wasn't until I well into college that I figured out that it was actually philosophy that I was really interested in and that I had therefore basically wasted (or I thought so at the time) a lot of time and energy studying the sciences.
As for what the experimental results mean, I don't know. But what I do know is that your statement that "photons are both particles and waves" is false. They are either a particle, a wave, or something else, but that are not both a particle and a wave.

Further, the fact that we cannot observe the contradiction doesn't remove the fact that the theory states and indeed is dependent upon the truth of the contradiction.



Now, as for the rest of what you said, the first of the two sentences quoted above is the killer. What is science if not the dispassionate pursuit of the truth concerning whatever it is that one is studying, whether it be physics, geology, astronomy, meteorology dog grooming, ditch digging, or whatever?

Regardless of how you answer that question the fact is that if you are willing to accept the possibility that reality can be in violation of the laws of reason, you remove from yourself the ability to know anything at all. The laws of reason are the very foundation of all knowledge of any kind, including scientific knowledge. Science cannot even be done without using reason. It is therefore irrational in the extreme to use science, which is predicated on reason, to argue against the veracity of reason, which is precisely what you just did.

Further, we can know that reality is independent of our perception of it. Imagine for a moment that everything is merely a figment of your own imagination. How would you explain you ability to imagine into existence a book written in a language you don't know which can be read by whole populations of people? How could you explain your ability to go to a school, spend years studying in or to gain the ability to go back and read the very same book that a year or more before you were completely unable to read? And, when you read the book, you find that it is full of concepts and ideas that you never thought of before but that you can look around you and see have been understood and implemented by thousands of others for decades or centuries?

All the astounding complexity and regularity around you and your own epistemological perspective insists that you don't really know for sure that any of it corresponds with reality.

If reality doesn't have to be rational, how do you know that anything is real? How do you know that your perceptions are real? How do even know that you are real?

Do you know that you are real?


Resting in Him,
Clete
 

Memento Mori

New member
No. I'm not a physicist, and there doesn't seem to be one that can answer the question. So it will have to wait.

What was the question? The whole metabolism thing?

Metabolic rates are too varied to make a solid test conclusion. This is why we go with other things that are more constant such as synchronized watches which run on an electric charge. The speed of the change is noticeable and easy to measure. I guess you could do it with an atomic clock which would be even more accurate.
 

Yorzhik

Well-known member
LIFETIME MEMBER
Hall of Fame
What was the question? The whole metabolism thing?

Metabolic rates are too varied to make a solid test conclusion. This is why we go with other things that are more constant such as synchronized watches which run on an electric charge. The speed of the change is noticeable and easy to measure. I guess you could do it with an atomic clock which would be even more accurate.
Metabolic rates only don't work because we cannot go fast enough. At high enough speed we can overcome the range of variation. What we need to know is... how fast can we go?
 

Memento Mori

New member
Metabolic rates only don't work because we cannot go fast enough. At high enough speed we can overcome the range of variation. What we need to know is... how fast can we go?

How fast can we go? That's more of an engineering problem. The SR-71 would have been your best bet since its normal cruising speed is around Mach 3 but it could achieve much higher speeds. But since you have to go a comparable percentage of the speed of light (300,000,000 m/s) to notice any real change (according to Special Relativity) and by comparison sound only travels at 343 m/s at 20°C (68°F). So, assuming you want to measure a human (as opposed to sending a satellite out and trying to achieve incredible speeds), it would be tough to get a person traveling fast enough to notice anything majorly out of whack.

Plus I have no idea how you would properly measure that because you would need an instrument which is inert to measure a person travel close to the speed of light. If the instruments were traveling the same speed there wouldn't appear to be anything wrong.
 

Gerald

Resident Fiend
All the astounding complexity and regularity around you and your own epistemological perspective insists that you don't really know for sure that any of it corresponds with reality.

If reality doesn't have to be rational, how do you know that anything is real? How do you know that your perceptions are real? How do even know that you are real?

Do you know that you are real?
Hey! Somebody left a big, smelly pot of overcooked philosophy on the stove!
 

chair

Well-known member
Metabolic rates only don't work because we cannot go fast enough. At high enough speed we can overcome the range of variation. What we need to know is... how fast can we go?

Why do you want to do this particular experiment? It is extraordinarily difficult, perhaps impossible, and won't prove anything beyond what has already been shown in other experiments.
 

Stripe

Teenage Adaptive Ninja Turtle
LIFETIME MEMBER
Hall of Fame
Well, I guess in order to argue with Relativity, one has to undermine all of science, and reality for that matter.

What a load of garbage.

Why do you want to do this particular experiment? It is extraordinarily difficult, perhaps impossible, and won't prove anything beyond what has already been shown in other experiments.

:rotfl: Real scientific of you, chair. We shouldn't do anything because it will just show us what we already know.
 

Memento Mori

New member
What a load of garbage.

Indeed. Clete's argument undermined everything about reality. I was simply noting it.

:rotfl: Real scientific of you, chair. We shouldn't do anything because it will just show us what we already know.

me said:
How fast can we go? That's more of an engineering problem. The SR-71 would have been your best bet since its normal cruising speed is around Mach 3 but it could achieve much higher speeds. But since you have to go a comparable percentage of the speed of light (300,000,000 m/s) to notice any real change (according to Special Relativity) and by comparison sound only travels at 343 m/s at 20°C (68°F). So, assuming you want to measure a human (as opposed to sending a satellite out and trying to achieve incredible speeds), it would be tough to get a person traveling fast enough to notice anything majorly out of whack.

Plus I have no idea how you would properly measure that because you would need an instrument which is inert to measure a person travel close to the speed of light. If the instruments were traveling the same speed there wouldn't appear to be anything wrong.

Well, I've put up why this experiment is nigh impossible. Do you have a better way of testing it?
 
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