1

General Science / Re: Has special relativity been refuted?

« on: 10/07/2018 17:57:00 »

But the apparent speed of the CMBR is the same no matter which way we look at it. Velocity differs from speed in that it includes a direction. It looks to me that your reasoning would indicate that we are moving away from the source of the CMBR at roughly 368 km/s, but because the source is all around us, that presents a paradox: in which direction are we moving 368 km/s?

Not quite
https://en.wikipedia.org/wiki/Cosmic_microwave_background#CMBR_dipole_anisotropy

2

Physics, Astronomy & Cosmology / Re: Is this formula valid?

« on: 07/07/2018 21:35:20 »

So what if we have the following formula?

Δλ = 2πγ/k

Can we introduce gamma to modify the wavelength due to relative velocity? Can this be a valid way of viewing orbitals?

No
Orbitals have three dimensional shapes and also odd properties that have to fit with the uncertainty principle.

3

Physics, Astronomy & Cosmology / Re: The Graviton?

« on: 05/07/2018 21:46:55 »

However, real gravitons propagate away to infinity, as oscillations on the gravitational field. This is what LIGO detected. (And real photons propagate away to infinity, as oscillations on the electromagnetic field. This is what telescopes detect.)

LIGO detected gravitational waves as predicted by EFE not gravitons. Gravitons are theorized to exist and have such low energy levels that we can not detect them with todays technology.

If gravitons exist (Gravity can be explained with a quantum theory), then gravitational waves would consist of gravitons.

Bosons can not escape a BH, a graviton is a 2 spin boson how can it get out of a BH. A gamma ray cannot escape the event horizon of a BH and it has significantly more energy.

Gravitons can't,  but since gravity would be mediated by virtual gravitons, this is no different from the fact that photons can't escape a BH, yet a BH can have a charge and an electromagnetic field mediated by virtual photons.

Gravitational waves definitely exist gravitons might not exist, and might not have enough energy to escape a BH.

Gravitational waves can't escape a BH either (By this I mean that gravitational waves cannot get out from inside the event horizon anymore than electromagnetic waves can.)

4

Just Chat! / Praise for Evan_au

« on: 28/06/2018 11:16:09 »

@evan_au  just received on the Naked Scientists Twitter:

Project STREET WISE
@wise_project 50m50 minutes ago

I really enjoy reading evan_au comments on the @nakedscientists forum! 🤖 #isotoperesearch

5

Chemistry / Re: Is it possible to create a gelatinous metal?

« on: 26/06/2018 14:37:53 »

This may be of interest.
https://www.sciencedirect.com/science/article/pii/S0010854513000131

Interesting find, but I don't think it is directly relevant--the gelators discussed in the article contain metal atoms, but they are not metallic. Rather, they are organometallic or metal organic complexes (these are the sorts of compounds I study, though not for making gels).

6

Physics, Astronomy & Cosmology / Re: Why is energy observer dependent?

« on: 24/06/2018 13:15:33 »

This states that L = V + U.

Correction. L = T - V, where T = Kinetic energy and V = Potential energy. If the potential is a velocity dependent one then the letter U is used. This is particularly important in electrodynamics.

7

Physics, Astronomy & Cosmology / Re: Is it possible for something to absorb light without reflecting it?

« on: 21/06/2018 12:12:46 »

A "black body" comes close to a perfect absorber. If you drill a small hole in a large hollow sphere, almost everything that enters the sphere stays inside it.

8

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 20/06/2018 17:41:33 »

the fabric of space

Please set down the physical characteristics of this wondrous fabric. Density? Elastic modulus? Viscosity? ε_FS and μ_FS?

If I can move relative to it, what is it fixed to?

9

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 20/06/2018 07:30:06 »

Wholly different experiment, wholly different result.

In my experiment the source does not move during the measurement.The only moving part is the locally oscillating part of the receiver, and the measurement is of the Doppler shift between the fixed and moving parts of the receiver when the direction of the incoming beam is fixed.

Your "ring experiments" are also irrelevant. c is the speed of light in vacuo, not in a medium. c_m is subject to all sorts of variations.

10

Physics, Astronomy & Cosmology / Re: Can time emerge?

« on: 16/06/2018 13:32:11 »

A related concept (looking through the other end of the telescope): Can time disappear?

This is subject to the same proviso as is the original question; namely, how do you define time?

If time is just a measure of change, the question should be: can change "disappear"?

11

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 15/06/2018 16:58:39 »

David c.#76

The house example is only intended to show all observers aren't required to have the same perception or point of view, even without motion.
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and with such a model you get event-meshing failures unless you go to a block universe model,

 
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There are no such things as 'event-meshing failures' (your invention).
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Stop pretending that SR makes no such claims. SR claims that there is no aether, and in doing so it ceases to be a mere theory of perceptions.

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I don't have to pretend. All experiments to detect any effect of an ether have failed. Einstein called it superfluous and developed SR without it, yielding the same coordinate transformations as developed by Lorentz.
If you understand perception, then you know the brain is a complex process which behaves according to rules of physics, specifically chemistry. That is also 'reality'. Medical science can monitor this activity and 'map' certain areas to a corresponding activity. It's not just inanimate clocks that run slow when moving fast, but also biological clocks.
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one-way speed of light is always c relative to any object it passes

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SR does not state that. It does state "the measured speed of light relative to an inertial frame is c. In #72  the relative speed of light was overlaid in the A frame to show the round trip time (2.31) would be the same.
If U and A had the same perception about everything, why have transformations?
------------

No - it's plain contradiction. If its true that light passes A at c relative to A and that it also passes B at c relative to B while A and B are moving relative to each other along the same line, you must have light overtaking itself as it travels between A and B because it's moving faster than itself.

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Your interpretation is flawed. You are not compensating for time dilation and length contraction for both A and B. Those motion induced effects alter perception.

12

The Environment / Re: Is the greenhouse effect a stupid mistake?

« on: 15/06/2018 03:40:59 »

So if a CO2 molecule absorbs outgoing radiation at x nanometers, it also emits at x nanometers,

This bit is essentially correct. (there are several complications having to do with non-radiative energy transfer, rotational-vibrational coupling, and doppler shifts, but these wrinkles don't change the overall effect)

so has no net effect on amospheric temperature. Doesn't smell right to me.

This bit isn't correct, and shouldn't smell right

The key here is that the direction of the emitted light is essentially random. This means that any EM of the appropriate frequency can't have a direct path from the ground our to space. Instead, it must take a random walk in which the mean free path is determined by the molar extinction coefficient of the absorber and the concentration of the absorber--and since the molar extinction coefficient is fixed, increasing concentrations of absorbers lead to shorter mean free paths, and increasing delays before the EM leaves the atmosphere.

To maintain thermal equilibrium, the rate at which energy leaves the Earth must be the same as the rate at which energy comes in (which is largely constant). So if it takes longer for a packet of IR energy to get from the ground to space, to maintain this same rate of energy going out, there must be more packets of IR energy in transit simultaneously. This is effectively the same as saying that the atmosphere must be hotter (at least where the increase photon density is). (ie it does have an effect on atmospheric temperature)

13

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 13/06/2018 16:08:48 »

David C.#73;

There is something contradictory though when you assert that both accounts of events are true in terms of what has actually happened. Things would be fine if this stuff was just being pushed as a theory of perception, but it isn't - it's being pushed as an absolute account of reality in which contradictions are generated by the business of having one's cake and eating it.

If 10 people form a circle around a house, each will have a different view of the house.
There are 10 simultaneous views, each different from the others.
Who has the true/real view if there is only one house?
This simplest of cases shows the question is meaningless. If there were x people, all x  views would be correct, relative to each person. The statements are true concerning the images, but each image is incomplete regarding the house. All the images collectively are incomplete since they only provide information about the exterior of the house. The statements are about perception, not about the house.

In science, information is verified by measurement. Experiment has demonstrated that motion affects measurement and perception. There is no expectation that two observers moving at different velocities will make identical measurements or receive identical images of events.
In the last example, U makes measurements from his location and assigns local times to events. In the U frame, A is moving at v and light is moving at c.
A makes measurements from her location and assigns local times to events. In the A frame, U is moving at v and light is moving at c.
Each can say light is moving at c-v or c+v relative to the other, but not relative to themselves. They have no means of that type of measurement.
All an observer has is measurements and perception.
 
"it's being pushed as an absolute account of reality"

FALSE, since 'RELATIVITY' makes no such claim, and has no need for the concept 'absolute'. Why is the 1905 paper titled "On the Electrodynamics of Moving Bodies", and not some variation of "Relativity"?
The common phenomenon of induction was one example that didn't need an absolute reference. Move the magnet or move the coil, there was still current flow. Which object was 'really in motion' was irrelevant.

You miss the point of the principle of relativity.
Time dilation: (the most often misinterpreted)
The 1st postulate states physical processes occur the same way in any inertial frame.
1. If A observes the B-clock moving past him at high speed, it's perceived to run slower than the A-clock.
2. If B observes the A-clock moving past him at high speed, it's perceived to run slower than the B-clock.
It would be a contradiction of postulate-1, if both observing the same process, got different results. It would also be a strange world with no predictability. 
The math (algebra and geometry) consists of equations that are symmetrical with respect to A and B. It's as simple as swapping A and B in the 1st statement to form the 2nd statement.
What you call contradictory is actually reciprocity

14

The Environment / Re: Is the greenhouse effect a stupid mistake?

« on: 13/06/2018 07:40:16 »

In summary, you seem to be saying that clouds dominate the radiative heat transfer to and from the surface of the earth. That is obvious to anyone who has ever stood underneath one, but it seems to have escaped the notice of so-called climate scientists who persist in counting fleas like CO2 and CH4 whilst studiously ignoring the H2O elephant they are riding on. Thus leading to statements like "global warming has altered the rainfall pattern" when it is obvious that the rainfall pattern is what determines global temperature.

15

New Theories / Re: Was a white hole the source of the Big Bang?

« on: 10/06/2018 21:12:32 »

What part of differential geometry do you suspect I do not understand. I assume you talking about grads divs and curls

No. That's vector calculus. The basics of differential geometry are described here:
http://www.newenglandphysics.org/physics_world/ma/ma.htm

16

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 10/06/2018 11:37:30 »

No.

ε₀ and μ₀ are measured in entirely separate, static experiments.

If the value of c depended on direction, at least one of these would have to be a vector so you would always get different values for either ε₀ or μ₀ depending on the polarity of the applied electric or magnetic field. You don't.

For anyone with a real interest in experimental physics it is worth noting that the relative values of ε_xyzand μ_xyz for some materials are indeed anisotropic tensors and the magnitude of c does indeed vary with the orientation of the material. The fact that the resulting birefringence effects are independent of the orientation of the material with respect to the fixed stars, phase of the moon, or anything else, strongly suggests that there is no aether or other universal frame of reference, so c₀ is independent of direction.

17

Physics, Astronomy & Cosmology / Re: Does general relativity encompass quantum mechanics?

« on: 09/06/2018 16:57:34 »

Well if GR and QM are BOTH inconsistent near to a black hole then that is something they have in common. So it is not necessarily a problem.

It's not that simple.  What it really comes down to is that each theory does make predictions when pushed beyond certain limits, but these predictions don't match reality.  When you try to apply GR to the realm where Quantum effects become noticeable, it doesn't match what we actually see happening.  On the other hand,  QM fails to make accurate predictions (such as gravitational effect) when you get to larger scales.  It not enough to just say "Well, this theory only applies to this point and no further".  The only time this is a valid argument is if this limitation is a built in part of the Theory itself. An example would be FTL speeds and SR.  c as a limiting speed is built into SR.   There is nothing in GR  itself that says it shouldn't give accurate predictions below a certain scale.  What is being looked for is the reason that these two theories don't make the correct predictions under certain conditions, and yet give very accurate results otherwise.

18

Physics, Astronomy & Cosmology / Re: Can we measure the one way speed of light?

« on: 07/06/2018 16:22:22 »

I was thinking of this one

" The coordinate transformations reduce to
x’ = γx, and t’ =γt.
Thus speed = distance/time.
If x/t = c, then x’/t’ = x/t = c
The reason, motion alters perception and measurement.
This satisfies the 1st postulate of SR since the expressions using x and t are the same for all inertial frames."

You presume too much from us
For example you mentioning the "1st postulate of SR"

I thought everyone participating in these 'relativity' subjects was familiar with the 1st and 2nd postulates of SR.
The 1st: the description/equations of physics is the same in any inertial frame.
Example:
The expression x=vt should work in any frame.
With light speed =1, on Earth, Al calculates the distance of object D as x=vt/2=1*8/2 =4 lyr. ( He needs a return signal)
In a spacecraft moving at .5, past Earth, toward D, he calculates x=.5*7=3.5 yrs.
As an anaut in a pseudo rest frame, he has to allow for length contraction of the universe as it moves past him at .5 in the opposite direction.
Does the moving anaut cause the universe to contract by moving extremely fast? No.
Do the particles in an accelerator cause the universe to contract by moving at near light speed? No.
This is actually his perception or interpretation of events, to reconcile the effects of time dilation.
On Earth D was 4 ly distant. Now, in his craft, it's arrived early, according to his clock (biological and mechanical). He can't deny his time nor his speed, so the only thing left is distance. If he sent a signal to D as he passed Earth, his conclusion would be the same, lc, i.e. verified by measurement.
The formula does not require any modifications.
In a world of absolute motions, you would have to know the location of the center of mass or absolute reference frame,) which is impossible in a dynamic universe. That's the beauty and utility of Relativity.
Imagine if you could have a conversation with someone, anywhere on Earth without requiring a translation.

19

Physics, Astronomy & Cosmology / Re: Is there such thing as inertial rotation?

« on: 07/06/2018 13:09:14 »

I pulled out my old undergrad text by Haliday and Resnik and looked it up to be certain. It is called "rotational inertia" and represented by I just like mass is represented by M. The cool think is that they have similar expressions for kinetic energy. In general I is a tensor.  But in many cases it can be written using a scalar. In that case the rotational kinetic energy = (1/2)I*omega^2   where omega is the angular speed. Look familiar?  Sort of like K= (1/2) M*v^2

20

Physics, Astronomy & Cosmology / Re: Is there such thing as inertial rotation?

« on: 07/06/2018 01:05:59 »

So that unless acted on by an external force an object would continue rotating with a constant angular velocity.

Yes. It's referred to as rotational inertia and can be calculated. Look it up in Wikipedia.