Three certainties in life: Death, taxes and the speed of light – wait no, maybe not that last one Einstein was incorrect about the speed of light being a fixed constant in our universe, a new theory suggests. A team of physicists are backing an idea that the speed of light is not constant and have made a prediction that can be tested. The speed of light is exactly 299,792,458 metres per second, and is a value that is …
I thought the speed of light was a constant by definition.
Only as part of a hypothesis.
Newton did impressively well, Einstein took it further...but the probability that Einstein had it all figured it is....well...vanishingly small. We're just waiting for the next step.
I can solve problems.
Slow it down, speed it up, slow it down, speed it up, slow it.... does light friction exist? This tech. ("light") would work great as a scroll saw in my wood shop. At the gym, could I just increase the speed of my personal light to make it look like I'm doing a hard workout or at least slow the light of everyone else? Also, it would be nice to slow the light of internet ads, tweets and likes to 0mph if possible. How about markup? <light speed="0">You'll never see this</light>
The future looks bright for this "light" tech., I keep an eye out for solutions.
The speed of light is a constant from a given frame of reference. Thus in order for someone traveling near c to see the speed of light as a constant, time must slow down for them relative to an observer in a different frame of reference.
You're always traveling at the speed of light through 4D spacetime, so the faster your travel through 3D spacetime the slower your travel forward in the time dimension. Perhaps inflation is related to the speed of light in a similar manner.
Though if inflation causes the speed of light to be faster as theorized here, that 5th "inflation dimension" must be an imaginary number to work within the x^2 + y^2 + z^2 + t^2 = c^2 framework.
"the probability that Einstein had it all figured it is....well...vanishingly small. We're just waiting for the next step."
The probability that he had it all figured out is precisely zero. Many more advances in cosmology and quantum physics have been made since his days. But of course, many widely studied theories are still untested and therefore not accepted a\s fact. The idea of a different speed of light at the birth of the universe as an alternative to the theory of rapid inflation to explain what we observe in the cosmic microwave background radiation is an interesting one. If it could be proved or disproved by the proposed experiment then that would be a great step in the progress of physics. But it wouldn't invalidate general relativity, my guess is that it would mean that the cosmological constant may not have been constant after all. I for one hope that we'll see an answer to this soon(ish).
No, see for example: "How the Universal Gravitational Constant Varies", http://www.sheldrake.org/about-rupert-sheldrake/blog/how-the-universal-gravitational-constant-varies
Likewise, physical laws are often violated, eg. "NASA's Physics-Defying EM Drive Passes Peer Review", http://www.forbes.com/sites/briankoberlein/2016/11/19/nasas-physics-defying-em-drive-passes-peer-review/#1034b01076e2
Unless, of course, nothing in the universe is constant which leads to an infinitely variable universe which leads to the concept of an infinite universe which leads to the concept that there is no such thing as time - each instant of time is a one-shot configuration of the universe. So to travle in time one would have to reconfigure the entire universe to a previous configuration to travel back in time or reconfigure the entire universe to configuration that has not yet occurred to travel forward in time. That would get a bit difficult with an infinite universe, not to mention an infinitely variable universe.
“Why is geometry often described as 'cold' and 'dry?' One reason lies in its inability to describe the shape of a cloud, a mountain, a coastline, or a tree. Clouds are not spheres, mountains are not cones, coastlines are not circles, and bark is not smooth, nor does lightning travel in a straight line... [b] [u]Nature exhibits not simply a higher degree but an altogether different level of complexity[/u] [/b].” – Benoit Mandelbrot
What Mandelbrot has introduced is the concept of fractional dimensions. And fractions, being infinite, leads to the concept of infinite _dimensions_ on both larger and smaller scales.
Constant?
> leads to the concept of infinite _dimensions_
Erm, no. That's a pretty fundamental misunderstanding of what fractional dimensions are.
To take the example you mentioned, of coastlines not being circles, the length we measure depends on the length of the ruler we pick to measure it. The fractal part is due to self-similarity at various scales and the overall "crinkiliness" of the thing being measured.
The thing is/things are:
* physical law determines that things have to bottom-out at the Planck scale, so any weirdnesses observed with your set of rulers is merely an epiphenomenon when compared with c/Planck-based metrics
* Mandelbrot's "nature" is not the same "nature" as in the "nature of reality" (whether it be relativistic, string-theoretic or multiversal or whatever); Mandelbrot's "nature" is stochastic and has underlying power laws
* using relativistic rulers is by definition the "wrong thing" when dealing with the fundamental nature of things; it's like measuring how "plaid" the universe is
* something like the fractal/Hausdorff dimension is a mathematical abstraction, not a real "dimension" (again, see power laws)
Besides, just because there are fractions doesn't mean that there have to be an infinite number of numerators and denominators (and associated explanations for them as separate things) in the universe. Unless you want to try to argue that, your argument falls apart.
I thought Trump had shown that taxes aren't either.While taxes are always there, they're never constant. During the election campaign, taxes are going to decrease. After the campaign is over, they increase. I believe some call it Pompous Git's Law ;-)
"Unless, of course, nothing in the universe is constant which leads to an infinitely variable universe which leads to the concept of an infinite universe which leads to the concept that there is no such thing as time"
That sounds infinitely improbable. Would you like a nice hot cup of tea?
the concept that there is no such thing as time
The End of Time (book)Julian Barbour, a British physicist with research interests in quantum gravity and the history of science advances timeless physics: the controversial view that time, as we perceive it, does not exist as anything other than an illusion. The philosopher J. M. E. McTaggart reached a similar conclusion earlier in the 20th C.
THX1138v2= Welcome to the Buddhist Religion..
The Universe has Always Been Here.. and probably goes on Forever..
With actual Infinity, Time is not relevant, any possible numeric system is actually Zero..
and so are we.. Do the best you can and try to do no harm..
IMHO= Becoming Aware is a wonderful experience..
All of our maths and sciences attempt to help achieve.. Nirvana.. RS.
"I thought the speed of light was a constant by definition. If you allow the speed of light to vary, then another measurement would need to be defined as constant."
The meter would need to be defined as a constant. The second is defined separately, the speed of light is defined as a fixed number of meters per secon, and the length of the meter is derived from that.
"The meter would need to be defined as a constant. The second is defined separately, the speed of light is defined as a fixed number of meters per secon, and the length of the meter is derived from that."
Except that defining the meter using the speed of light is a later modification to the definition. When the meter was invented and defined, the speed of light was not known.
When the meter was invented and defined, the speed of light was not known.The metre was invented on 17 March 1791. Ole Roemer estimated the speed of light at 200,000 km/s in 1675 and James Bradley gave the number 301,000 km/s in 1728.
Today of course Merkins know that it's 299792.4574 ± 0.0011 km/sec and the British know that it's 299792.4590 ± 0.0008 km/sec.
The metre was invented on 17 March 1791. Ole Roemer estimated the speed of light at 200,000 km/s in 1675 and James Bradley gave the number 301,000 km/s in 1728.
So the kilometre was used for measurements 84 years before the metre was invented? This relativity business truly is weird.
Yes, estimated. But in km/s? That was clever :-)Hopefully the smiley means you are just being a smart-arse :-)
Roemer never made the estimate in Earth-based measure; the conversion to km/s is so the modern reader can comprehend and compare. Huygens' estimate for example was a value of 110,000,000 toises per second, an amount incomprehensible to most people today (possibly when it was made, too). At El Reg it really should be percentage of maximum velocity of sheep in a vacuum, but I couldn't be arsed to work it out.
speed of light in a vacuum is assumed to be a constant. however, our velocity through time would have to be NOT decelerating for that to work... bremstraelung from tachions? interesting thought experiment.
*ahem*
Anyway, light speed in a vacuum is the absolute maximum speed something can go relative to something else. hence relativity.
light can, and does, attempt to go faster than it's supposed to through a medium and creates cerenkov radiation [did I spell that properly] aka "that blue glow" you see in photos of nuclear reactors operating in open pools of water. Those are various particles being forced to move slower because they hit water [and its speed of light is just a bit slower than the particle].
if our velocity through time is NOT a constant, i.e. is slowing down [or maybe speeding up] then light over time wouldn't be going "the same speed" any more. I wonder if THAT is what they're basing their theory on? yeah ok 'velocity' is time-based, so "changing velocity through time" simply means (by my definition) that the time axis isn't change at the same 'rate'. 1 second may not be 1 second a zillion years ago, in other words. If time flowed differently back then, the speed of light would ALSO be different [being based in time]. It would also mess up relativity calculations like E=mc^2 and so mass and/or energy is no longer a constant. damn them!
now I'll want to know where the mass and/or energy WENT to (or CAME from) when it changed over a zillion years' time.
now I'll want to know where the mass and/or energy WENT to (or CAME from) when it changed over a zillion years' time.I think you spotted the fatal flaw. Although it's "merely" an assumption that mass/energy is conserved, if it's not then there's a whole HEAP of physics out the window. Holy shit, Bob. I seem to have CAUGHT whatever it is YOU'VE got... ;-)
Relativity and classical electromagnetism (JCM got tantalizingly close to discovering special relativity if he hadn't died so young) only assume speed of light is constant for any observer in any frame of reference.
Admittedly it raises problems if it varies day-day but there is no problem with it being different in the early universe.
@Mage - It creates more problems for theoretical physics. However, all theories are our best navel gazing explanation for what we see. They are not necessarily very accurate or even true and when more observations and analysis is done their areas of wrongness and limitations will become more obvious. The fact they are testable means we have an idea of the area of validity.
"Not just Einstein, but Maxwell and others."
I didn't understand half the letter. But it's argument was that gravity and "light" (massless particles) dodn't propagate at the same speed. That's undoubtedly weird, but not necessarily fatal.
And while the author argued it was light that was faster, I saw nothing to say it couldn't be gravity that was slower (it's all relative...). Slower gravity is plausible if gravitons self interact -- they would naturally find the earlier universe stickier than the present day one.
So I read this as yet more evidence we don't understand gravity. Which, yes, means more problems for Einstein (cf dark matters vs MOND). But Maxwell, in as much he survived being mugged by Dirac and Feynman, is fine.
Not if we designate this new, faster light "C++".
Then the sums about "c" still make sense (mostly, for given values of "sense") but Science can still Be Done.
e.g. E=m(C++ - SCF*)
SCF - the Stevie Correction Factor needed to nudge C++ back towards c so the sums work again.
Job done.
The constant is the sleed of light "in a vacuum". So, maybe we can have a negative vacuum to increase the speed of light.
OK - stupid - but since the constant governs everything we see,
A) I am not convinced their experiment will prove anything and
B) So what that it happened 13b years ago. How will that help anything today (like us getting to the nearest stars before we blow ourselves up).
Alan
or perhaps our current "vacuum" isn't a vacuum at all, perhaps it has something that we haven't detected yet, but this "something" was more/less abundant previously. Thus in the same way light is altered by the refractive index, this "something" also has a refractive index that is negative to our eyes (or rather our definition of a vacuum being 1 is wrong)
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