swansont

! Moderator Note ChatGPT is like predictive text with a larger database. The results are fictional. What is the goal of this thread?

Right. And we’re discussing the equation at the end of section 2, which Logicandreason just acknowledged as being correct, and why Einstein claims that clocks will not be synchronous between the two frames.

Radiated power of ~2 x 10^18 watts, mentioned in the abstract of the paper, is probably why we aren’t doing it, and why it’s detectable.

LOL, that’s not what superposition means.

But, when combined with the first postulate, “Any ray of light moves in the “stationary” system of co-ordinates with the determined velocity c, whether the ray be emitted by a stationary or by a moving body” the result is that speed of light must be the same for all (inertial) observers, since any frame can be considered a stationary frame. But Logicandreason isn’t challenging the postulates as being in error.

! Moderator Note You need to cite some peer-reviewed work to support this position, because assertions aren’t going to cut it.

Different events? No. They are both tracking the light traveling from A to B and back to A. Yes, there is error in “classical” physics, in assuming that everyone measures the same time interval. That’s one of the points of the paper! It happens because of the constancy of c. If light acquired the speed of the source, as with other phenomena, the times woul be the same. Also true, owing to relativity, but in “classical” physics they would be the same. But this is all based on the constancy of the speed of light, which is a postulate of relativity. It is not what “classical” physics reports. We have not analyzed that case.

It’s more than this; it’s that each of the times in the moving frames are different than in the rest frame, and more importantly, the round-trip times will be different in the two frames. Einstein showed that the time for a tick is different in the rest frame (trest = 2r/c if a tick happens once per round trip) than the ticks in the moving frame because the round-trip time will differ. He didn’t explicitly show this because it’s pretty obvious. The people one would expect to read his paper (physicists) would know this.

I haven’t been paying attention to Mordred’s line of discussion. I’m more interested in your contortions to deny the algebra I presented. If you can’t come up with the equation I requested -it’s pretty simple - you really have no business arguing that my derivation is wrong (and it isn’t; but you have to not fabricate statements that you attribute to me)

A little math/physics might explain why (imagine that!). What signal strength is needed for detection, and what can be supplied? That will tell you how far away you can expect it to be effective. The deep-space network that communicates with e.g. the Voyager craft have the power drop off by a factor of around 19 orders of magnitude. It’s a bit more than 10^9 km. The inverse-square law is brutal. It works because we know what signal we’re looking for, so it can be picked up among the noise. That’s ~10 light-hours. A signal that goes light years (at least ~1000x the distance, so a million times more attenuation) would need a proportionally larger power to stand out. You can boost reception with an larger area, but DSN starts with a pretty big dish. Who is “we”? Link? Who is doing this? edit: looks like SETI is using data from the VLA, and not doing it as a dedicated search. The large aperture and number of dishes bumps this up to possible https://www.seti.org/press-release/massive-radio-array-search-extraterrestrial-signals-other-civilizations ”COSMIC operates commensally, which means it works in the background using a copy of the data astronomers are taking for other scientific purposes,” said Paul Demorest, Scientist and Group Lead for VLA/VLBA Science Support at the National Radio Astronomy Observatory. “This is an ideal and very efficient way to get large amounts of telescope time to search for rare signals.”

So robots, not alien life. And yet we were just subjected to a thread where alien beings are allegedly sighted. You can’t have it both ways. Citation?* The US government classifies material for which “unauthorized disclosure could reasonably be expected to cause damage to the national security” (serious/exceptionally grave damage for secret/top secret. The thing is, the US only represents a small fraction of the world. Why so many sighting in the US? The US can’t classify info from other countries - why not get data from sources outside the US? *edit This says it was the CIA, and that the docs were declassified in 2011 https://www.cia.gov/stories/story/secret-writing-cias-oldest-classified-documents/

The Voyager missions were approved in 1972 and launched in 1977. It takes time to build and test a space probe.

You asked a question, so this was moved into the mainstream physics section. “Alternative” views need to be raised in the speculation section.

A proton and electron would accelerate in opposite directions in an electric field. F= qE (positive meaning directed in the +x direction) An electric field can’t be both positive and negative at a given point.

You can’t use your pet theory about QM to conclude anything about how mainstream physics treats the issue.

Yes. They would have trouble dropping in and visiting the surface of a planet that has higher gravity than what they’ve become adapted to. Their muscles would have atrophied and they would have a lower bone density, relative to the original state. (the sci-fi show “The Expanse” touches on this, using 1g to torture someone who’s adapted to lower gravity) It’s why one can infer that it’s likely that any aliens sighted on earth, if there are any, must be adapted to something close to our gravity.

Nomadic aliens need to get their material from somewhere. There’s an energy cost to this - maneuvering, going in and out of gravity wells, for both the main craft and whatever is used for retrieval from wherever they are getting the stuff. Then there is the time spent these “oases” where they are using up these resources, which dictates how much material has to be obtained, and how big the ship needs to be. That’s the analysis that always seems to be absent or glossed over A being adapted to low-g would have difficulty existing in higher-g environments. For a being adapted to much higher than 1 g, they might not have developed space travel at all, owing to the energy required to lift payloads into space.

I takes years to prepare this kind of a mission.

We don’t have a simple ruler, we have equations. which is r, so this is unnecessary This is vt, so also unnecessary The goal is to get to an equation that only has the total time, r, c and v in it, so you need to eliminate these other times from your derivation. I will wait for you to show this Good thing I didn’t do this, then Show me where I did this.

Then it’s potentially dangerous. You could burn yourself if you touched it, etc.

Protons and electrons would be pushed in opposite directions by this electric field. i.e. pushed apart. If it has an electric field it is by definition electromagnetic

That’s interpretation, though. An aid to understanding. A concept, not an object. This has nothing to do with the topic under discussion.

What are the two times? We are considering the case where the light and rod are traveling in the same direction. I have not replaced r with ct. I replaced d with ct. d is the distance the light travels as it gets to the end of the rod. This should be blatantly obvious. It’s simple algebra. That time does not appear in my derivation, as it’s unnecessary. If you want to use it in yours, go ahead. I never claimed this. You’re misreading the derivation. I’m not doing this, so this is moot. ct is the distance the light travels. vt is the distance the rod moves. (v is the speed of the rod) Since the light has to go the length of the rod plus the distance the rod moves, it travels a total distance of r + vt But we know the total distance is ct Thus we know that ct = r + vt No. But it’s used in derivation of the equation. He rearranged the terms. But if you multiplied both sides by c-v, you would end up with a ct term, as anyone who can do basic algebra can see. Can you do basic algebra? It’s about enforcing the rules of the forums, which I do, and you do not. That’s not an equation. ct is not the rod length. You berated me for allegedly saying this (I didn’t) and now you are claiming it. Shouldn’t you be yelling about how you can’t think your way out of a paper bag, or something? You are doing the problem in a different fashion. There’s often more than one way to do it. But what I asked for was the equation for the time (not numbers) using the same terms Einstein used, for the case of the light moving in the same direction as the rod. Here’s the thing, though: I don’t think you are conversant in algebra, and I think your reading comprehension is poor. I think you haven’t done what I ask because you don’t have the ability to do it. Prove me wrong. If you don’t derive the equation, I will lock the thread. You don’t get to dictate this. There is only one instance: the light travels from A to B There is a different time for light traveling from B to A, but I have not derived that. You might notice that is a different equation

Just so you know, it’s the insults that will be why you get banned. t is a variable. c is a constant. I never claimed that ct was constant. v is a variable, too. t is the time it takes for the light to get from one end of the rod to the other. There is only one value for this time. I did not say it was equal to the rod length. Yes, I did say that. The rod is moving. In the time it has moved a distance r, the rod will have moved, so light will have not reached the end. I asked you to derive this expression, but you did not. All you’ve done is insult people. ! Moderator Note So, one chance: you derive the expression for the time it takes for the light to go from A to B, in terms of the known terms of r and v, as well as the speed of light. (i.e. the terms in Einstein’s equation.) for the co-propagating case, as I did. You haven’t done so until you give the correct expression in terms of the same parameters.

It certainly requires more insisting that the limitations of c aren’t a problem. Rigorous analysis instead of hand-waving, just as happens in science. Even then, an analysis is required.