12-26-10, 06:05 PM #801
Originally Posted by MD
You're saying you can't measure the velocity of a moving object with a laser rangefinder because Einstein got it wrong.
And you're saying you can't explain your theory, you have no 'ansatz', just a vague description that conveys nothing useful or even interesting.
12-26-10, 06:09 PM #802
12-26-10, 06:17 PM #803
Well, bro, you better get onto the Pentagon and fill them in. They will have to adjust to this new information you have, and that right quickly!
There are a lot of pilots waiting to land somewhere. I'm not sure how they're going to take the news that they can't tell where they are.
12-27-10, 02:58 AM #804
www.arxiv.org to see the level of detail and complexity people are doing.
You clearly have trouble accepting reality, when you claim things happen which experiments, aka reality, refute. The methods of timing and measuring distance used by relativity are used in the GPS network. Millions of people put their lives in the hands of such systems every single day. If it didn't work would the military use it?
That's the ultimate knock down punch to your claims. You can't claim a conspiracy in the scientific community when it produces results seen by non-scientists. If a Cruise missile kept missing a target by 20km someone would notice, but they are extremely accurate. If your in-car navigation kept telling you to turn where there is no road, you'd notice. Reality might not be exactly as described by relativity but its so close we currently can't measure a difference. We can measure a difference between your claims, reality doesn't work as you assert.
12-27-10, 04:10 AM #805
Originally Posted by MD
Ok then. I suggest the following thought-experiment instead.
Recall that the speed of light is c=299792458 m/s. Expressed in units of light-seconds per second, this value is c=1 light second per second.
Now, consider a spaceship of unknown length moving at unknown speed. A light beam is fired from the back of the ship to the front and the one-way travel time is measured. The measured time is 2 seconds.
A light beam is then fired from the front of the shop to the back and the one-way travel time measured again. This time, the travel time is found to be 0.6667 seconds (i.e. two-thirds of a second).
Question 1 for Motor Daddy: How long is the spaceship?
Question 2 for Motor Daddy: How fast is the spaceship moving?
These should be easy starter questions.
Now for some harder questions:
Question 3 for Motor Daddy: Is it possible to measure the speed of light, or must it always be assumed that light travels at exactly 299792458 m/s? Don't bother telling me it has a defined speed, etc. etc. I know that. I'm asking you: if you try to measure the speed of light experimentally, is it possible to do so, and will your answer match the defined value? I'm not concerned about whether you think such an experiment would be a waste of time, either, since you already know the speed of light etc. etc. Just answer the question.
Question 4: If it is possible to confirm the speed of light by measurement, can the experiment be done in any reference frame other than the hypothetical "absolute zero speed" reference frame and still give results that match the defined value of the speed of light?
Question 5: Would it be possible for somebody on the spaceship above to measure the speed of light, without knowing the speed or length of the spaceship in advance?
Question 6: If the answer to Question 5 is "yes", can you please give a procedure for measuring the speed of light. (Note: if the hypothetical measurer needs to work out the speed or length of the spaceship as part of the procedure, that's fine, but make sure you specify how they would do that.)
Question 7: Does it make any sense at all to talk about the speed of light relative to the spaceship?
Question 8: If the answer to Q7 is "yes", then what is the speed of light relative to the spaceship? Is it different to the absolute speed of light (299792458 m/s)?
I look forward to your answers. I feel like we're making progress towards a mutual understanding here. Maybe I can be convinced that there really is an absolute frame of reference after all.
12-27-10, 04:19 AM #806
I've been reading your other responses and I found this interesting:
Originally Posted by Motor Daddy
So, when people such as builders of houses say the house has a certain length, say, they aren't quoting the real length at all (because the Earth has a velocity through space). Their rulers probably aren't calibrated correctly, and even if they were they wouldn't work properly on a moving Earth.
Is that right?
12-27-10, 07:45 AM #807
Light traveled 199,871,631.7486 meters in space in the time it took light to travel from the front of the ship to the back of the ship (.6667 seconds of light travel time).
The ship traveled 399,713,284.2514 meters in 2.6667 seconds, so the ship's velocity is 149,890,607.96 m/s.(rounded off).
The ship traveled 299,781,215.92 meters in 2 seconds and the light traveled 599,584,916 meters in 2 seconds. That means the ship is 299,803,700.08 meters in length.
Last edited by Motor Daddy; 12-27-10 at 08:30 AM.
12-27-10, 08:50 AM #808
12-27-10, 03:56 PM #809
You are admitting that you'd have to measure light transit times in EVERY POSSIBLE DIRECTION for your procedure to work, (even in your fictional universe). That means you can't say things like this:
Because you don't know if the ship is moving in any other direction, other than the obvious "rear to front" direction. What if the ship is also drifting upward and sideways through your fictional "absolute frame?" Then your above calculation for the length of the ship would be wrong.
The velocity calculation would also be wrong, unless you qualify it by saying that you are only concerned with one component of velocity -- that from "rear to front" of the space ship.
12-27-10, 04:32 PM #810
Originally Posted by Motor Daddy
How can you lay a stick on the ground of unknown velocity and measure the time it takes light to travel the stick, and then conclude you know the length of the stick?
You only arrive at an elapsed time of an unknown length and unknown velocity. Worthless information.
However, you can ultimately measure the speed of light using my method to determine the length and speed of a stick, to go on to measure the speed of light. But you must always first know the length and speed of the stick.
12-27-10, 05:28 PM #811
12-27-10, 07:22 PM #812
If you randomly choose any two pages in this thread and compare them, you'll see that they're pretty much the same. MD just keeps saying the same thing over and over, and doesn't really pay any attention to anything to the contrary.
12-27-10, 07:27 PM #813
12-27-10, 07:31 PM #814
Tell me the length of the ship that James R. posted. Tell me your numbers, buddy.
Last edited by Motor Daddy; 12-27-10 at 07:37 PM.
12-27-10, 07:33 PM #815
12-27-10, 07:35 PM #816
12-27-10, 07:36 PM #817
Let me guess. 2.6667 seconds round trip divided by two equals 1.33335 seconds each way, so the length of the ship must be 399,728,273.8743 right?
I mean, if light always travels at 299,792,458 m/s, and light traveled 1.33335 seconds in each direction, that means the ship must be 399,728,273.8743 meters in length.
That's funny right there, I don't care who you are! You're only off by 100 million meters.
Last edited by Motor Daddy; 12-27-10 at 07:45 PM.
12-27-10, 07:42 PM #818
MD, you're a major league crank, well over the ubercrackpot line. Nothing that's ever said to you will make any difference in what you believe.
The fact that Einstein's relativity has been amply demonstrated by observation, experimentation, and prediction, to an extreme degree of accuracy mean nothing to you. On the other hand, your version of reality has never been demonstated at all. It just exists inside your head, and than appears to be a very strange place indeed.
12-27-10, 07:47 PM #819
I repeatedly told you it is a waste of time to measure the speed of light, it is defined!
How do YOU know the time it takes light in a vacuum to travel one metre? Did you look it up on Wikipedia?
What if it's wrong, like Einstein? Wouldn't it be a good idea to make sure the definition is correct? So HOW would YOU check it?
No wonder I have to repeat things over and over and over.
12-27-10, 07:48 PM #820
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