1

Just Chat! / Re: Is Time Dilation related to Dark Energy?

« on: 12/06/2021 23:46:58 »

I still feel that a photon from an ancient galaxy has more time dilation than one from a more recent galaxy closer to us

That idea would put this topic into New Theories rather than cosmology. As @Halc says, there is no meaningful ‘time for a photon’, so to speak of 2 photons having different time dilations is meaningless.

Just chat is not a good place to put questions like this one.
If you have a new idea or variation on an established theory then New Theories is the place.
If you have questions of clarification about the current understanding of dark matter or expansion of space then best to put them in the physics, astronomy, cosmology section.

@Zer0 you are on the right track. If you look at the SR equations you will see that as an object’s speed gets closer to the speed of light (relative to us) the time it experiences and distance  travelled tend towards zero (important word that  ). So to talk of any object travelling at the speed of light, relative to us, experiencing time is meaningless, such a traveller would arrive instantaneously, so again differences in time dilation are only possible for sub-light objects. Best not go there - there lies philosophy 

2

New Theories / Re: New theory of modern science

« on: 10/06/2021 08:45:28 »

But I don't believe some of them are true.

And the recurring theme on your part for that disbelief is the argument from incredulity.........

.........That tells me you don't understand the theories as well as you think you do. I'll give you the benefit of the doubt and give you a chance to prove yourself. Can you explain ito us what the Big Bang theory is, why it was proposed in the first place and why it is currently the most accepted theory for the origin of the Universe?

Good idea, but let’s up the ante somewhat and include Higgs Boson. Let’s also say that @charles1948 is limited to only posting in this thread until he’s has convinced us.
Not just copying from say Wiki, but own, detailed understanding and include sufficient detail on why you don’t believe these are true - no fallacious arguments either.

On any other special interest forum (on any topic) persistent naysayers would be banned, here we are more tolerant and allow alternative views to be expressed in this section. Anyone who persistently posts alternative theories in the main section will be limited to this section only, particularly where those views disrupt valid discussions on a topic.

3

That CAN'T be true! / Re: Why are TROLLS being Allowed to run Amok?

« on: 09/06/2021 08:34:25 »

I do not wish to be drawn into a discussion on conspiracy theories, but as one has been posted it might be appropriate to explain why I do not consider them to be science subjects, but more often politically motivated. Typically a conspiracist will use some true facts, but hide other facts so presenting only one side of the events. I will use the one posted here as an example.

Let’s start with an assertion that triggered the posting of this conspiracy theory.
The assertion that Wiki tells lies about people (specifically Jimmy Dore) because it is controlled by (unnamed) powers, is in itself a typical conspiracy theory. Unnamed organisations or ‘powers that be’ are often quoted in conspiracy theories, but strangely those same powers can either tell lies or the truth depending on which side of the political fence you sit.

The specific conspiracy theory Jimmy Dore is accused of supporting is that based around the gassing of civilians in Syria. Supporters of the Assad regime, and Russia, claim the attack was set up by the opposition to draw the US into taking action against Assad.
They point to the OPCW investigation of alleged chemical weapons use in Douma, Syria which concluded that gas canisters were dropped from the air. A whistleblower claimed that a suppressed report said the gas canisters were placed on the ground rather than dropped from the air as reported by eyewitnesses. As with most conspiracy theories it is based on a true incident and this has been reported in mainstream media.
This is mentioned here as the version promoted by Jimmy Dore:

No, the scientists on the ground, in their now suppressed report, suggested the barrels were most likley placed at the location.

Like most conspiracy theories, this only puts forward one side of the story, which as we will see is not as presented.

The OPCW refused to comment directly, asking for an independent enquiry into their investigation. That enquiry concluded that the excluded report was not written by one of the team who visited the site, that the author was not a member of the Fact-Finding Mission that worked on the Douma investigation, and was in a support role that denied him access to much of the information the FFM handled. His excluded report contained diagrams of a gas cylinder that did not match photographs from the scene and was misleading as it omitted damage to the cylinder harness caused by impact to the ceiling and subsequent impact on the floor of the room below. So this ‘suppressed’ report was not by “the scientists on the ground” but was by someone who wasn’t in the team, didn’t visit the site, and which contained errors. I wonder why it was not included?

Unfortunately, the excellent journalist Robert Fisk was drawn into the controversy when he quoted a doctor who claimed that the victims where suffering hypoxia due to panic. Whether that doctor saw actual victims is questionable, but other eyewitnesses including first response medics and hospital workers noted foaming at the mouth, one of the signs of chlorine gas poisoning. Other evidence from the site noted the corrosive effects of chlorine gas around the cylinders which caused corrosion of metal objects nearby.
I have a great deal of respect for Robert Fisk and I am certain that he reported what he found in interviews. The Independent certainly gave a lot of coverage to the Douma attacks, but as far as I am aware they didn’t give the same coverage to the results of the independent enquiry into the OPCW report as other newspapers eg https://www.theguardian.com/world/2020/feb/07/inquiry-strikes-blow-to-russian-denials-of-syria-chemical-attack

Why would Jimmy Dore promote this conspiracy theory? The cynics among us would say controversy increases viewing figures, which increases advertising revenue. As Jolly says, it’s all about money.

Just a word for Jimmy Dore. In one of his programmes he says of 9/11, that no other Tower has collapsed due to fire either before or after this one. Well Jimmy, look at the Tacoma Narrows bridge, no suspension bridge before or after that was destroyed by the wind; so do you think someone blew it up with explosives?
Keep smelling whatever it is you are drinking!

“woe to the arrogant as they will destroy themselves”.

4

Just Chat! / Re: What is that Black String around peoples wrists?

« on: 09/06/2021 00:00:50 »

I've Noticed this in different cultures, traditions, regions, religions...

A Black String tied around the Wrist.
➰
What is the Significance or Meaning of it?

Apparently it is from Hinduism to ward off evil spirits or evil eye.
It seems to have been adopted by various pseudomystic groups

Most people seem to have one nowadays, hence Curious.

Most people???
I don’t have one and I don’t know anyone who does. Now, I know I haven’t been out much recently, lockdown and all, but I’m sure I would have noticed if Boris or the Queen had one, or the postman, etc.

5

Physics, Astronomy & Cosmology / Re: TV documentary about Arthur C. Clarke

« on: 08/06/2021 08:12:23 »

This was answered here https://www.thenakedscientists.com/forum/index.php?topic=80548.0

6

Geek Speak / Re: What is the power of regression?

« on: 06/06/2021 23:44:19 »

This sentence on it's own isn't particularly true or helpful to the OP but it is interesting and ironic as you say.  The OP needs to know that we have a useable statistical model. 

It is very difficult to know what the OP needs. He appears here at intervals with seemingly disconnected questions, with no context, and often no response to requests for further information on his application. Who knows whether it’s helpful as we rarely get feedback.
This sort of question is typical: https://www.thenakedscientists.com/forum/index.php?topic=81458.msg625626#msg625626.

7

Physics, Astronomy & Cosmology / Re: Concerns, is everything in the universe in motion???

« on: 04/06/2021 12:23:42 »

Due to Special Relativity, all things are in motion in relation to one another

Incorrect, that isn’t due to SR. SR does not assign a cause to the motion.
Also, as has been pointed out, not everything is in motion relative to all things.

8

New Theories / Re: What is the beginning of point A?

« on: 02/06/2021 16:42:05 »

Are there any measurble limits of ignornce density?

None, it is infinite 

9

Chemistry / Re: what is this molecule please?

« on: 01/06/2021 16:06:16 »

I'm more worried that William Hardy just seems to post bits from wiki pages without adding to them or even crediting them.

Plagiarism if not copyright issues. I would like to see them credited @William Hardy

10

Physics, Astronomy & Cosmology / Re: Can we turn waste plastic into rocket fuel?

« on: 29/05/2021 08:55:54 »

I`ve read an article about green rocket fuel that was made by some private space company.

Why do you say ‘some’ private company, as if you didn’t know who they are. They are the same company you have been trying, unsuccessfully to advertise throughout all your topics.
Do it again and you are banned

11

General Science / Re: What does the following mean (Particle Physics question)?

« on: 27/05/2021 15:43:39 »

P.S. - Please, keep up the Good Work!
✌️

Do not encourage trolling

12

General Science / Re: What does the following mean (Particle Physics question)?

« on: 25/05/2021 18:20:30 »

The thing about a brick, though, is that you can pick it up in your hand. Look at it.
...............

Thanks Evan.  You make interesting points. I don't believe the Higg's Boson actually exists though! Do you?

The search for the Higgs Boson is similar to the discovery of Neptune.
There were some discrepancies in the orbits of the outer planets that if correct would throw into question Newton’s laws of gravitation. An astronomer calculated that it could be explained by another planet and calculated where it should be. Observatories looked at that location and confirmed it was there.

You remind me of the people who would not believe in bacteria or viruses, because they couldn’t see them.

I suppose you don’t believe tornadoes are real either; after all, they are only fluctuations of the air so they can’t be ‘real’ can they.

I suggest as well that you learn something about bubble chambers. You keep quoting them but obviously don’t know how they work. If you did you would realise why it is ridiculous to keep quoting them.

Are there Popes on here?

Yes, you are one.
The Pope was trolling Galileo.

13

New Theories / Re: What exactly is gravity?

« on: 25/05/2021 16:48:09 »

01  It is true that as long as the elevator is on the ground, light beam moves out from one hole to the other in the opposite direction.

Not so. If the elevator is on the ground it is in a gravitational field and light will bend.

02  Unless there is a change, up or down, there is no change or something is changing and it is scientifically proved only.

No, there doesn’t need to be a change, just a static gravitational field.

Based on this information that:
It is only when the elevator accelerates forward that light beam is moving down.  It is true that,
basing on these information that Einstein predicted bending of light by Gravity.  So as per the above information I had predicted that Gravity is moving down within the elevator and bending light.  Further it is also clear that it is only when the elevator accelerates, clearly indicates that unless Gravity field changes or moves there is no change in the movement of light.

This is a misrepresentation of Einstein’s thought experiment and of actual experiments.

I had written above hypothesis based on Einstein thought experiments only.  Those information is collected from the books only.

Once again, I reiterate that I never misrepresented the facts. 

Yes you have misrepresented, because Einstein never said that in his thought experiments.
Show the pages from the books or this will be locked.

14

NAKED SCIENCE - THE OFFICIAL BOOK / Re: Hello Spammers?

« on: 25/05/2021 14:39:53 »

The first rule of spam club is you don't talk about spam club.
:-)

And you certainly don’t invite anyone to join 

15

New Theories / Re: What exactly is gravity?

« on: 23/05/2021 23:15:52 »

It is known and proved fact that Sun is rotating on its axis. 

Agreed

Ok, when Sun is rotating:
"Mass tells space time how to curve and curved space time in turn tells mass how to move".

That has nothing to do with the sun rotating

So, naturally curved space or Gravity field of Sun is also moving.  What  else proof is needed.  Light bending clearly indicates this.

You are misrepresenting the equivalence principle and Newton.
Provide proof that the gravitational field of the sun is moving and this is responsible for light bending, or we will lock this topic.

16

New Theories / Re: What exactly is gravity?

« on: 23/05/2021 18:51:26 »

As long as the elevator is at rest or stationary on the ground, light beam moves out from  one hole to other hole.

In the thought experiment the elevator is on the ground and so it is in a gravitational field. The light will not go out of the other hole, it will hit the wall below the hole.
You do not need a changing gravitational field to bend light.
In the experiment where the gravity of the sun bends starlight the sun’s gravitational field does not change.

17

New Theories / Re: What exactly is gravity?

« on: 23/05/2021 17:37:02 »

Ok, if the space ship accelerates from ISS and if there is gravity due to acceleration, I am sure that I will accept that mine hypothesis is wrong.  What is there.

You accept that in the ISS the astronauts are in freefall and feel no gravitational force, this will be the same in a spaceship alongside.
If that spaceship accelerates at 9.8m/s² the astronauts will feel a force pushing them towards the back of the ship and that force will be the same as that due to gravity on earth. It is not gravity (which is due to the attraction between masses) but it is equivalent to gravity.
This has been proven by astronauts travelling to and from the ISS.

18

Physics, Astronomy & Cosmology / Re: Problems with PopSci articles in GR. Should we stop using one example?

« on: 23/05/2021 16:54:42 »

The sudden disappearance of the sun is much more like an example situation to help visualise something about GR.   It simply doesn't fit the criteria to be considered a "thought experiment" (IMHO).

I agree, but I am pretty ambivalent about it's use.

I've never used it directly myself. In the thread mentioned I was interested in pointing to the latter half of the article in the link and hadn't even noticed that this example had been used - notice he also uses the breaking string example. Therin lies a problem, because even if we don't use it directly, it is so widespread that suggesting someone read such and such an article, website or paper might well direct them to this example, and not all those will be Popsci it will include well respected experts in GR.
Anyway, 'nuff said on this before I get on to misrepresentations of QM!

This is a quality resource and it has kept me occupied for hours. Thank you, thank you.  I think you've already pulled the text that is most relevant to this forum thread and put it directly into your earlier post.
I don't seem to have much disagreement with or from you, Colin.

John is one of those really nice guys who is also an excellent researcher and thinker. You should find something on his site about thought experiments in general. Lots of good material and he’s happy to share.

  Any student wishing to follow this example through more carefully with some Mathematics can find a way to provide that acceleration to the sun.  They can add stiff strings, photon rockets or high momentum incoming ping-pong balls if they need to.  The main thing is that they don't hit a wall that stops them proceeding with the Mathematics as soon as they look at the E.F.E. and realise that the proposed stress-energy tensor isn't even continuous let alone differentiable.

Haven’t had chance to read through all the latest posts, but this point caught my eye.
The objective of this site is outreach to a general public and interested amateurs to try and stimulate an interest in science. As such it is very unlikely that the average questioner will understand tensors, let alone stress-energy tensors. For that reason the level of answer we give is very different from that on say physicsstackexchange.
Take this question which is somewhat typical "How long could humanity survive if the sun went out?" https://www.thenakedscientists.com/forum/index.php?topic=82152.0
(Note: We have also had " What would happen to the earth is the sun suddenly dissapeared")
We don't answer this by starting to discuss nuclear fusion and the technicalities of why the sun cannot suddenly blink out, and the audience expects little maths, just a straight forward answer they can understand.  Obviously some of the questions go a little deeper, but in general we don’t expect to go much beyond school physics in terms of technical understanding.
I don’t say this to put you off your quest, but just to put some perspective for this site.

Can I make one plea on terminology. A gravity wave is one where the returning force on the displacement is gravity eg a water wave. In GR we refer to gravitational waves to differentiate.

I think it is a mistake to characterize gravity as 'action' at all. It's a field, not something that radiates towards us.

I think you, like me, enjoy looking at physics from different perspectives and use the most appropriate at the time.  I remember as an undergrad we were set the exercise of deriving Newton’s laws from GR in the weak field limit, a useful reminder that in the approximations they are still valid.
I assume you are familiar with the work of Fokker, Tetrode & Schwarzschild and the Wheeler, Feynman analysis of this in terms of electrodynamics and particle action. It’s an interesting look at the relationship between field theory and stationary action, bit old but still interesting, particularly coming from action man himself.

19

New Theories / Re: What exactly is gravity?

« on: 22/05/2021 05:31:29 »

You are proposing that in a gravitational field, if the elevator is at rest then only light beam will bend.  If that is true, what is there need for Einstein thought experiments.

 
The need for the thought experiment is to show that acceleration and gravity are equivalent. This can be shown by comparing the case above with an elevator in no gravitational field, but accelerating. The light beam bends in both cases, they are equivalent.

Einstein thought experiments propose that if the elevator attains acceleration, equal to acceleration light beam will bend,

i think you missed out the words due to gravity so it should read

“if the elevator attains acceleration, equal to acceleration due to gravity light beam will bend”.
In that case, yes this is correct.

in case, if it attains velocity, equal to  velocity light beam will bend in opposite direction.

not so, don’t know where you got that from. Show your source. It has nothing to do with velocity, just acceleration.

Further you have also proposed that in no gravitational field, acceleration bends light.  I don't think there is any such proposal by Einstein. 

Yes, that is the proposal from Einstein.

I think you are equating acceleration to gravity. 

YES, YES, YES. but not equating as in they are the same thing, but that the effects of both are equivalent.

Ok, if that is true, if a space ship accelerates from Moon or from a space station, do acceleration equates gravity.

If you are in a spaceship travelling at constant velocity you will feel weightless. If your pilot then accelerates at 9.8m/s² then you will feel a force pushing you against the back of your seat equivalent to the force of gravity. That force will be equivalent to your weight on earth. Yes, the acceleration is equivalent to gravity.

Forget light for a moment and consider a tennis ball.
Spaceman in no gravitational field (or freefall) feels weightless. If they push a tennis ball away from them it will go in a straight line to the opposite wall (as would light).
Now the spaceship starts to accelerate, the ‘bottom’ wall of the ship moves up and pushes against the feet of spaceman so he has to use leg muscles to stand; if he now pushes the tennis ball away it will fall towards his feet, exactly the same as if he were standing on earth in a gravitational field. Acceleration and gravity are equivalent.

20

Physics, Astronomy & Cosmology / Re: Problems with PopSci articles in GR. Should we stop using one example?

« on: 20/05/2021 18:51:26 »

Would you care to put a number to the mass of a photon? 

Think you can put a value on the equivalence substituting hf for E in the famous equation

In principle you can derive a relativistic mass for the photon, but this is not often used nowadays.
The m in E=mc² is rest mass, more properly m₀, which for a photon is 0, so E=0 for m₀. The energy of the photon is in the second part of the famous equation E=pc and it is possible to have momentum without mass.
Because all forms of energy (of which mass contains a lot concentrated in a small volume) affect spacetime it is easier to use energy as the common currency rather than mass.