| Author | Message | ||
     Aesquire |
... *length* is currently defined in terms of the speed of light being fixed. But formerly length was defined by color. Color is length. That's not circular, length has always been referenced by some thing... | ||
| Hootowl |
“ We're saying that you don't know that, and cannot know that since by defining the meter in terms of c, we've no way to verify it. To verify that the speed of light remains constant requires a unit of length that is independent of the speed of light. Yes?” No. A meter is defined as a wavelength because that wavelength is a meter. A different frequency would result in a different distance between wave crests. The meter was not always defined by a wavelength. It was redefined as a wavelength because that wavelength was a meter. Anyone anywhere in the world, regardless of temperature, humidity, or altitude can reproduce the exact length of a meter. A standard must be repeatable. But, you’re an engineer. I don’t have to tell you that. It can be defined that way because the speed of light is constant. You could measure it in hamsters, its speed would not change, nor would the distance from peak to peak at any given frequency, assuming no difference in velocity between the observer and the light source. (No doppler shift.) There’s that relativity nuisance again.  | ||
| Sami |
Jeff, I never said we should ignore everything we learn in the interim. That being said, it is not a fact that the speed of light is a constant. GPS proves otherwise, because these satellites are programmed with variable speeds of light, not with constant speed of light. Velocity, acceleration, altitude and other factors affect the speed of light, hence using the speed of light as the measuring standard is like using a rubber ruler. You have said that ''space time'' changes instead of the speed of light, but that is unsubstantiated. Further, spacetime is meaningless in QM. Patrick, If color is length, then what is length? If length is defined in terms of the speed of light and vice versa, then that makes our measuring standard viciously circular. We've got a chicken and egg problem here. How about the singularity? There was no light, no space, no time. Then there was light. Was light constant at that moment in time and space? Or did it evolve over time and space? | ||
| Sami |
Those scandalous clocks Ronald R. Hatch https://worldnpa.org/abstracts/abstracts_5789.pdf | ||
| Blake |
Jeff, Your still not addressing the issue being raised. The speed of light is measured in terms of the meter, which is defined in terms of the speed of light. So then, if c were very gradually slowing, how could you measure (detect) that? By declaring that it doesn't change? Excuse me, but that isn't science. That's faith. And FYI, the meter is no longer defined by wavelength, at least according to wiki. The meter is now defined as "the length of the path traveled by light in a vacuum in 1/299,792,458 of a second", which is just to say that the meter is defined as the product of the speed of light in a vacuum (c) times 1/299,792,458 seconds. Regardless, even for the prior definition of a meter in terms of wavelength, measuring EM wavelength directly involves the speed of light, yes? Inflation? Hello? | ||
| Sami |
Did the big bang really happen? https://www.newscientist.com/article/mg18625061-80 0-did-the-big-bang-really-happen/ | ||
| Hootowl |
I don’t see the issue, Blake. A meter is how far light travels in a second. That’s as deep as you need to go. Measure a second, measure the distance. It’s not self referencing. Please excuse my incorrect citing of the meter reference. I had forgotten they changed it again. Also please excuse my reference to doppler shift. It was a poor analogy. | ||
| Aesquire |
The Meter WAS redefined in '83. I think they messed up. They had it right before. But the wavelength of a given element's quantum emission is the same in the same reference frame so a guy in Detroit or Tycho crater can get the same readings, and a part made either place should be interchangeable. ( machine shop attitude ) The assumption ( well proven, locally ) with GPS is the speed of light is fixed in vacuum, and by reading the clocks you then know how far away they are. The positions are known and the rest is fairly simple math. Time dilation should be built into the algorithm, and is tiny at the speeds involved. Using wavelength to define length works even at high speed. But only locally, ( same vector and speed ) preferably in the same G fields. The problem with the assumption that light is a constant is we live in curved space. We provincial limited beings assume that's "normal" and call the space near a Neutron star severely curved, and the space between galaxies flat. If we understood gravity better, we'd have a better grasp on this... https://www.dictionary.com/browse/meter The 1960-1983 definition is exactly the same dimension as the later one. Just "measured" differently. Things get funky in highly curved or differently curved space. Color is energy too! But when you get real small, fast, big, hot or cold stuff acts weird. Slow is a bit hard to define since we're always moving. Earth spins, falls around Sun ( our mutual center of mass ) which falls around the Galaxy, which is falling towards... | ||
| Hootowl |
“ A meter is how far light travels in a second” Of course, this is completely wrong, and I again apologize. Not sure what I was thinking. Light travels a light second in a second. Now that is circular logic. But light traveling ~300,000 kilometers in a second, well there’s nothing circular there. | ||
| Sami |
Patrick, there is no time dilation. What is changing is the speed of light, not time itself. Space isn't curved, time isn't dilated. Curvature and dilation are relativistic assumptions. Defining the speed of light as constant and using that for defining the meter is faulty reasoning. See quote below explaining that light travels faster than c. Jeff, light can travel faster than ~300,000 kilometers in a second. If gravitational fields are present the velocities of either material bodies or of light can assume any numerical value depending on the strength of the gravitational field. If one considers the rotating roundabout as being at rest, the centrifugal gravitational field assumes enormous values at large distances, and it is consistent with the theory of General Relativity for the velocities of distant bodies to exceed 3 × 10 8 m/sec under these conditions. An Introduction to the Theory of Relativity, William G. V. Rosser, 1964, p.460 (Message edited by Sami on April 10, 2020) | ||
| Hootowl |
Huh? A rotating body, whose circumference us sufficiently large would have angular velocities that exceed the speed of light? Is that what you’re saying? If so, what would accelerate those bodies to that speed? There isn’t enough energy available. If you instantaneously converted all the matter in the universe, save one electron, to energy, and directed it at the sole remaining electron in the universe and could, with 100 percent efficiency, use that energy to accelerate that electron, there would not be enough energy to make it exceed the speed of light, which is an absolute limit. Matter increases in mass as it approaches the speed of light. If it were to reach the speed of light, it would have infinite mass. You cannot alter the speed or direction of an object with infinite mass without an infinite amount of energy. There is not an infinite amount of energy in the universe. In fact, we used nearly all of it trying to get that electron up to speed. If that’s not what you meant, I’m afraid I don’t get it. | ||
| Sami |
The speed of light is not an absolute limit. Matter does not increase in mass when approaching the speed of light. Accelerating bodies in vacuum to a high speed costs energy, but once they have reached that speed it doesn't take energy to maintain. I agree that there isn't an infinite amount of energy in the universe. Also, if what you're saying is true, then you cannot at the same time believe in inflation which requires speeds faster than the speed of light. | ||
| Hootowl |
Space expands. Think of stars as dots on a balloon. Blow up the balloon. The stars aren’t moving, space is expanding. Some parts of our universe are expanding such that they appear to be moving away from us at speeds faster than light. They aren’t. Space is expanding. They aren’t moving through space. They are moving with space as space expands. There is a significant difference. | ||
| Tpehak |
If 2 lights moves in opposite directions one light has 2x speed of light speed against another. | ||
| Sami |
Space isn't expanding. I'm familiar with the expanding balloon model, but that's just a thought experiment, not reality. We are not living on a space balloon. You say that space expands, but that is philosophically incoherent. If space is expanding, then what is it expanding into? Into nothing? | ||
| Sami |
Tpehak, ''If 2 lights moves in opposite directions one light has 2x speed of light speed against another.'' Indeed. If you move with 60mph away from me and I move with 60mph away from you, then we move 120mph away from each other. | ||
| Hootowl |
“Matter does not increase in mass when approaching the speed of light” It increases in mass at any velocity. It approaches infinite mass as it approaches the speed of light. Where are you reading otherwise? You should let the folks at CERN know. I’m sure they’d love to save some money on their power bill. | ||
| Sami |
Jeff, matter doesn't increase in mass. What increases is the energy required to accelerate a moving body. | ||
| Hootowl |
“what is it expanding into? Into nothing?” We don’t know what, if anything, is outside our universe. I’m not sure we can know. But I’m betting God exists out there, or how could He have made this universe? How could He have existed before the universe? The very fact that the universe appears to have a boundary answers the atheist “gotcha” question of how God could have created something from nothing if He couldn’t have existed before there was something. He existed before this universe because He exists outside of it. Perhaps He created many universes. That, too, is theorized. Einstein once said “The more I study science, the more I believe in God.” | ||
| Hootowl |
“matter doesn't increase in mass. What increases is the energy required to accelerate a moving body.” I’d like you to really think about what you just said. | ||
| Hootowl |
Important note, when we talk about mass, velocity, and energy, we’re talking about relativistic mass. | ||
| Blake |
Jeff, Just to be clear... The meter is now defined as "the length of the path traveled by light in a vacuum in 1/299,792,458 of a second." Agreed? Question> If the speed of light were somehow doubled, what would happen to the apparent length of the meter? During the same 1/299,792,458 of a second, the now double speed light will travel double the distance, yes? If you then used that doubled meter unit of length to then measure the speed of light, what numerical answer would you get? The number of meters between two points stationary relative to each other would be halved with the doubled in length longer meter, yes? So the double light speed will be ascertained to cover half the distance in half the time, indicating that the speed of light in terms of m/s has not changed. But the seed of light has doubled. If the speed of light changes, and the unit of length (the meter) is based upon the speed of light, then you have no way of detecting a change in the speed of light. | ||
| Hootowl |
Good thing the speed of light in a vacuum is constant. Some scientists say this may not always be the case, but at this point it is pure conjecture. I thought we were sticking to science and the observable universe. | ||
| Aesquire |
Conjecture? Nigh perfect word for it. We have incomplete information on the subject, but locally, inside our solar system, it's a fact. Human knowledge is the poster child for incomplete information. There was a short short story in Analog many years ago. A report from an alien ship that responded to a distress beacon. They found a crashed starship on the back side of a Moon orbiting a primitive, pre FTL, forbidden to contact, civilization. ( us ) Unfortunately the crew was long dead, and the wreck had the FTL drive malfunctioning, and still trying to propel the ship. The responding ship recovered the bodies and vaporized the ship & evidence of the crash, before returning to their voyage. At the end the Captain and his engineer noted that the malfunctioning star drive had been warping space time for decades over a several light second radius. And joked that if the primitives had advanced far enough, the warped space would fool them into thinking light speed was a constant. Boy, wouldn't that mess up their view of physics! | ||
| Aesquire |
https://www.americanthinker.com/articles/2020/04/u seful_vs_useless_covid19_models_a_response_to_the_ armchair_analysts.html I will end with a history lesson from Francis Bacon, the founder of the scientific method. Bacon himself intended the scientific method ("the interpretation of nature", as he called it) to be not the whole truth, but rather only one part of it: Let there be therefore (and may it be for the benefit of both) two streams and two dispensations of knowledge, and in like manner two tribes or kindreds of students in philosophy — tribes not hostile or alien to each other, but bound together by mutual services; let there in short be one method for the cultivation, another for the invention, of knowledge. (Francis Bacon, 1620) | ||
| Aesquire |
If 2 lights moves in opposite directions one light has 2x speed of light speed against another. Nope. https://www.amnh.org/exhibitions/einstein/light/co nstant-speed And just to be contrary. https://en.m.wikipedia.org/wiki/Variable_speed_of_ light Now, I hedge my bets. I think the speed of light is constant in my local space. I don't assume that is universal. It may be. But I can't test that, although there are some scientists who have theories that are yet to be disproven. Time is certainly variable. Sitting in a waiting room at a clinic vs. riding a bike on a challenging singletrack. Obvious! | ||
| Hootowl |
“Indeed. If you move with 60mph away from me and I move with 60mph away from you, then we move 120mph away from each other.“ That’s true enough at that speed. Things change at relativistic velocities. Time is relative to the observer. I feel like a broken record. | ||
| Tpehak |
Which means there is no reference point in the space with zero speed. | ||
| Tpehak |
If you move with 200000 km/sec away from me and I move with 200000 km/sec away from you, then we move 400000 km/sec away from each other or 300000 km/sec away from each other? (Message edited by TPEHAK on April 11, 2020) | ||
| Sami |
Patrick, Francis Bacon was a secret alchemist, his scientific method is based on alchemical principles. The Secret Life of an Alchemist: Francis Bacon's Real Philosophy of Nature http://www.sirbacon.org/henryalchemist.htm Einstein's ''insight'' was not the truth. The scientific consensus is wrong on relativity, just as it's wrong on man-made climate change. Your link states: ''The speed of light is constant and does not depend on the speed of the light source.'' This is false, the speed of light does depend on the speed of the light source, as shown by the GPS satellites. Moreover, general relativity (GR) and special relativity (SR) make contradictory claims regarding the speed of light. SR depends on c being fixed, GR depends on c being variable. On top of that, GR contradicts QM. Jeff, there is no such thing as relativistic mass and relativistic velocity. Energy required to move an object faster does not mean that mass increases. You work with relativistic assumptions, which are thought experiments only and not the truth. Time doesn't change, space doesn't change, what changes is the speed of light. Speaking of a broken record, I feel just like that |
