Theoretical

https://en.m.wikipedia.org/wiki/Gravitational_wave "Although gravitational radiation has not been directly detected, there is indirect evidence for its existence.[5] For example, the 1993 Nobel Prize in Physics was awarded for measurements of the HulseTaylor binary system which suggest that gravitational waves are more than theoretical concept. Various gravitational-wave detectors are currently under construction or are in operation, such as Advanced LIGO which began observations in September 2015.[6]" "Gravitational waves are not easily detectable. When they reach the Earth, they have a small amplitude, meaning that an extremely sensitive detector is needed, and that other sources of noise can overwhelm the signal.[43] Gravitational waves are expected to have frequencies 10−16 Hz < f < 104 Hz.[44]"

I don't put that much trust in PMTs. Set your discriminator to 2MeV, place a strong 1MeV source near the scintillator/PMT. I'm betting you'll see a noticeable slight increase in count rate. Great method. We already know from experimentation that alpha particles don't become two alpha particles in cloud chambers, which is basically the idea he's proposing. I was just curious how he's getting the results.

Thanks. It could be insensitive to low energy gammas, but not 100%. His coincidences occur at such low rates, which seems to indicate it's gamma, or energetic electrons as you mentioned. I'm not sure what gamma energy range the alpha would produce colliding with the gold. I'd imagine there's an appreciable probability of it being at least a few MeV, no? Braking radiation.

Let's not confuse his gamma coincidence experiments. But yes he's probably using the same scintillation counters to detect alpha particles. That's more like it

Unfortunately I don't have much more information either. As the image shows he's using a Am-241. Am-241 emits low energy gamma. You should know that, rather than attacking me.

So I've been exchanging emails with Eric Reiter about his alpha coincidence experiment. Basically he claims to emit alpha particles toward a gold foil. The foil causes the particle to either reflect left or travel forward, detector A or B. But he claims a single alpha particle travels in both directions. He has a slab of Am-241 taken from a smoke detector. Not sure on the thickness. First off he claims two alpha particles are emitted from each nucleus traveling 180° from each other in both directions. Alphas from Am-241 have extremely low penetration depth. So it seems the alphas emit mostly from the nucleus of atoms near the surface of the material. What's the likelihood of Eric detecting two alphas traveling in opposite directions? Doesn't it seem like he's detecting gamma rays? As you can see in the following image, Eric claims to emit alphas toward a gold foil, which he claims splits the alpha particle into two half alpha particles. Yes, that's correct, two alphas that are intact. I guess one could call them sub-alpha particles. http://unquantum.net/wp-content/uploads/2012/10/alpha-split-demo-31.jpg According to my calculations there's insufficient energy to split the alpha. He says his alphas are emitted at 5.5MeV, maybe more like 5.2MeV. That's roughly one fourth the energy to remove a proton from the alpha particle. What about angular energy? The alpha is spinning as it's ejected. Or thermal energy? I think the probability of those being enough to split the alpha particle is low. At first I thought he was seeing a weak stimulated alpha emission. But now I have to wonder if he's just detecting gamma rays. Any thoughts? BTW, the mention of Eric measuring two alpha particles being emitted 180° apart from each other simultaneously is another experiment Eric did. That's not the alpha coincidence experiment.

The Wikipedia article gives the OP models and metaphors. This topic is extensive. Another area is frame dragging, https://en.m.wikipedia.org/wiki/Frame-dragging

Space itself is something. https://en.m.wikipedia.org/wiki/Metric_expansion_of_space "Distances increase as more spacetime fills in between galaxies"

Yes I'm certain it is. Thank you very much!!

Interesting. I had to look up that word, but I wonder if entering the null geodesic is path could solve this for me.

wait. You changed my experiment. It's not about measuring the speed light. It's about taking note that the signal clicks per second decrease when the mirror device is stationary near a massive body as compared to when it was far away. That's really all there is. So again, it took light more time to reflect a shorter distance. So what do you think about that experiment? For anyone who doesn't want to read the thread to know what the mirror device is. It's two parallel mirrors where light reflects back and forth. Each time light reflects off a mirror, the mirror device emits a signal burst / click / bleep. so the mirror device is a clock. The observer is always in the same location. The mirror device is either far away, or near the massive body. Obviously when the mirror device is near the massive body, it's emitted clicks per second decreases. both the observer and the mirror device are always stationary, except for the brief time in between experiment when the mirror device is traveling to its other location, which is either near or far away from the massive body. So this experiment is not about relativistic velocity, but is about gravitational time dilation.

Okay then that means you the speed of light makes no sense in terms of Relativity. Don't you see my point? Again: The mirror experiment is a clock. If we send the mirror device near a massive planet for some time, then when it returns it lost time. This means that if we have the mirror device emitting a signal every time the light beam reflects off a mirror that the far away observer will see less emitted signals per second because the mirror clock is running slower. And this will be verified when the mirror device comes back to the observer. Also, according to relativity the distance between the mirrors decreases when near the massive planet. Therefore don't you see that if it takes light longer to travel from one mirror to the other mirror, and the distance is less, that the light is traveling slower. Yes initially I saw a way out of this puzzle with the Four speed theory, but that doesn't seem to explain this because we know from experiments that the atomic clocks do not have to positioned in some preferred axis.

Hm I think it's back to the drawing board because I'm certain light travels at a slower speed when closer to mass *regardless* if the light is traveling toward or parallel to the mass.

I know but they change in opposite directions. The distance between the mirrors decreases near the massive body, and there's more time between clicks. But anyhow his post was referring to velocity time dilation, not gravitational. So it's irrelevant. Could the four velocity theory explain what I'm missing? As far as I can tell, if we use only 3 dimensions in explaining the mirror experiment, then it appears light travels slower, but if we use an extra dimension, a 4th dimension if you will, then the light always travels at c. I think this is it! What do you all think? https://en.m.wikipedia.org/wiki/Four-velocity So then if it takes light more time to travel between the mirrors, and the mirrors are closer together, then the fourth dimensional vector must increase enough to make up the difference. Correct? Yes I get the hint now! Using the 4th dimension balances it all out. Thanks! But hold on, there's more to this, right? This would mean that gravitational time dilation and length contraction only apply in the direction toward the massive body. I've read posts of people saying the same thing, that gravitational length contraction only applies on a certain axis. What do you think?

Thanks. Those are clear well done experiments that shows gravitational time dilation is real. So then what am I missing regarding my mirror experiment? We know that a clock that counts the number times light reflects back and forth between two mirrors will have lower counts if closer to a massive body than if it's far away from the massive body. We know that the distance between the two mirrors does not increase. In fact Einstein's equation says it contracts near the massive object. So if it takes longer from light to travel a shorter distance, then please explain why light is not traveling slower. I fully accept that light is not traveling slower, but I don't see how to explain this. It's probably something so simple and obvious.

I've seen those experiments. They're in good agreement with relativity. But that also takes into account the effect of light losing energy due to leaving mass due to gravity, right? While a stationary atomic clock on a massive body doesn't take that into account as far as I see.

What do you think of this experiment. They did two experiments. The experiment I'm interested in is regarding gravitational time dilation where the optical atomic clock slows down when slightly raised. The only questionable part is where do they take into account the fact that objects higher in elevation rotate faster. My iPhone calculator doesn't have enough precision, so I'll have to do it on my desktop some day to see if their results can be explained by velocity rather then gravitation. An improved experiment would be to move the higher elevated object at an appropriate speed against earths rotation so that it is moving at the scene speed when the clock was lower. http://tf.boulder.nist.gov/general/pdf/2447.pdf

I'm trying to see this through the time dilation equation, which says time slows down from an outside observer's perspective when an object gets closer to a massive object. Therefore, if the clicks per second decrease as measured by the observer, and the distance between the mirrors contracts, then how is that the same speed? The only explanation I see is that the outside observer will not detect any change in the clicks per second. Thanks. I see our post have crossed. I'll analyze your previous post. Ah, i'm referring to *gravitational* time dilation and length contraction. Perhaps that's the difference we're seeing here? t=tf*sqrt(1 - 2*G*M/(r*c^2)) d=ds*srqt(1 − 2*G*M/(r*c^2)) The only explanation I can come up with is that the far away observer will detect the same amount of clicks per second from the mirror device regardless of how close the mirror device is to the massive object. Do you think that's the answer?

Great, but that doesn't answer my original question. See the mirror example.

Meters / second. I don't see the hint. The equation says time slows down. That would mean light must take longer for each reflection. How are you seeing it? Yes, A person that is next to the mirror would of course detect the same amount of time since his detectors would also slow down, but we are talking about a far away observer. Could the missing piece of this puzzle be the effect of leaving such a massive body? One thing we can probably agree that's incorrect is an increasing out of sync with the mirror device. No?

Interesting. That creates an even bigger problem for me. Let's say the outside observer is watching the mirror device through a telescope. Each time the light reflects off one of the mirrors, the mirror device produces a bright flash of light for the observer. So as the mirror device remains stationary near the massive object, we are say the observer is detecting only one flash every two seconds, but that's impossible since it means light would have to be traveling slower in order to do that. As stated previously, the observer is becoming increasingly out of sync with the mirror device. So then what happens if the mirror device remains stationary near the massive object for an appreciably long period of time such that the observers out of sync time because so great that the mirror device could travel to the observer is less time? In other words, the mirror device would have traveled to the observer, but the observer would not yet have seen all of the clicks yet.

Thanks. So I gather that applies to the time between the clicks as well. When the mirror device is away from the massive object, let's say the outside observer detects 1 click every second. When the mirror device is close to the massive object, the outside observer detects 1 click every two seconds. What is the outside observer to think of this? He might be inclined to think that either the spacing between the mirrors increased or the light is traveling slower, or both. But what is happening is that the observer's reference to time becomes increasingly out of sync with the mirror device with each click? When the mirror device is near the massive object the observer detects a click at t=0, t=2, t=4, t=6..., but in reality the clicks occurred at t=x, t=x+1, t=x+2, t=x+3?

Maybe someone proficient in Relativity can point out what I'm missing here. According to the equations, time slows down when closer to a massive object. That's from an outsiders perspective since time doesn't change from ones own perspective. Also there's a length contraction closer to a massive object. I haven't found any solid answers regarding any possible change in the speed of light when closer to a massive object. I believe an outside observer sees no change in the speed of light, or does it. So then how is the following example explained. We have light bouncing back and forth between two mirrors. Each time the light reflects there's a click being broadcast so that an observer from a distant location can observe the clicks per second. So time slows down when the mirror device is placed near a massive planet. This means the observer who is far away detects less clicks per second. How is this possible if light is traveling at the same speed unless the mirrors are farther apart? But the mirrors aren't farther apart. According to relativity the mirrors are closer together due to length contraction. So how can the device be producing less clicks per second unless the speed of light decreased? I'm missing something here. BTW there are some discussions on length contraction near a massive object, but there are contradictory posts if the contraction occurs on every axises.