1

Just Chat! / Re: Is Nuclear War imminent?

« on: 03/10/2022 16:27:28 »

The real threat from nuclear weapons

The real threat from nuclear weapon is the weapon itself.
If something unexpected occure, this could lead to some automatic launch of those weapons (the automation is part of the weapon).
Per example, if some asteroid hit by chance some nuclear nation, how will the weapon system react ?

2

New Theories / Re: what is temperature?

« on: 18/09/2022 19:13:19 »

I dont agree with the explanation at 2mn30
He is doing the comparison of the "temperature" of two systems composed of the same objects.
One has more kinetic energy as the other, so it is hotter (this is what the guy say).
This is wrong.
I think he is doing confusion between temperaure and heat.
Temperature is not a concequence of heat, even if there is a possible link between the two concepts using mass !

He use a specific case (same molecules (same mass) in two systems) to demonstrate a false general conclusion.

Heat and Temperature are totally different things !
First, temperatures cant be added with temperature, but heat can be added with heat.

Here the guy is talking about heat, not about temperature.
To be convinced, just think about "tin air" (few molecules) : It has very low heat, but it can have very high temperature if the speed of the molecules is high.
You could grip it with you hand and dont be burned (no heat...) altought it has very hight temperature.

The best temperature measurement tool is the one who change the less the temperature measured (so when mass of the measurement tool tend to 0).
So here there is no heat involved at all (no "equilibrum" needed unlike the guy say incorrectly).
 
Now, yes the heat is also a mechanical energy, but he say it himself... it is a statistical mechanical energy.

3

New Theories / Re: Lifting One Weight Higher Than Another Drops

« on: 09/09/2022 23:06:05 »

For sure we can use gravity to gain energy.
Look at the space elevator.
https://en.wikipedia.org/wiki/Space_elevator

Almost every scientist actually agree with this.

You can climb the tether toward the sky and the tether stay straight "without countereaction", the centrifuge force aiutomaticaly pull the tether straight away (Noether is here out of date...).
You climb the tether but you dont have to change the couterweight position using any energy.
So yes, because they agree this, we must understand that almost every scientist actually agree that we can gain energy from gravity.

4

Chemistry / Re: what are the names of 2 solids that combust when they come into contact

« on: 09/09/2022 16:54:34 »

what are the names of 2 solids that combust when they come into contact
or repel away from each other violently

Antimatter ?

5

Science Experiments / Re: How to demonstrate polarization of light?

« on: 31/08/2022 13:07:01 »

I've already done several experiments with microwave. Here are some of them, which is relevant for explaining polarization.

Very good !
This kind of video is very helpfull.

I will try to do some comments about the experiences in the videos, one by one, just after viewing them.
I will perhaps say things you talk about in the other videos but i think it is better to do the comments just after viewing them one by one so as to stay with the facts.

Investigation on microwave 37 : blocking mechanism

So lets start gently with the "first" (number 37 here) : "Blocking mechanism".
The test of transmitance or passing thru (we cant say at this point if the wave is passing thru or re-emited) of the plastic material :
First glance, this material act as if there is no effect on the wave.

But more precisely, and not sure if you noticed : The value show on the wave receptor vary slightly when you move the plastic sheet.
When the plastic sheet stay still, it act as if it would have no effect on "the transmission" (this is how we can call this part of the phenomenon regardless of the internal behavior of the elementary physical objects within the matter) of the wave.
But if you move the plastic sheet, and during the move only, you have less "transmission".
And from there you could eventualy test some type of moving, rotation, upward/downward, backward/forward with this kind of "neutral" material.

Now, let suppose the plastic material is "neutral"

Your result :
1. Spare continuous vertical grid 6mm horizontal gap : 30% "passing" (you use the word "passing" word and it is probably better than using like me the "transmission" word, but we mean the same).

2. Dense continuous vertical grid 3mm horizontal gap : 0% "passing" (you use the "spare" and "dense" word but i think that saying that is almost meaningless (they are not categories), the distance in mm is the only usefull value).

3. Dense continuous grid, 3mm horizontal gap 10/10 vertical gap : 2% "passing".

4. Additional : Almost Same as 3 (the vertical gap is not 10mm but 5mm, this is what is suppose because you have 20 gap instead of 10) but the copper grid has been replaced by aluminium sheet.
In this case we have around 90% "passing".
I see it is the experience is suggested in my previous post.

Some basic criticism (perhaps you could correct the video) :
You give the grid spacing in mm but you dont give the wavelength of the emiter.
You forget to say the type of the polarisation of the wave; saying it is linear is no sufficient, you need to say the direction : Here the polarisation is linear and vertical.
We dont know "the tolerance" of the measure : Per example if the wave is polarised with the angle 90, is some wave polarised with the angle 92 received (with some loss of power of course) too ?
Same with the emiter : Whats the gauss (i suppose) power value around the mean ? (The variance).

More advanced criticism.
We dont really know if the grids are connected together (this could have some incidence on the result if we talk about electron movement)
You changed the copper with the aluminium (different materials so perhaps different behaviour) and also they do no have the same thickness.
Copper wire should be presented nacked so to be sure the plasic around it cant interfer with the result.
It is not clear what "passing" mean : Perhaps effect of the the grid is the rotating of the polarisation by exactly some angle and if you rotate the receptor by the same angle you will get 100% "passing".
Same with the wave length, perhaps the grid only change the wave length without changing the polarisation and the receptor is not well suited to receive these waves.
Perhaps it change both (polarisation rotation and wave length).
Something you could do to investigate the "passing" more accuratly is to verify that when you rotate the receptor (using per example steps of 10 degrees so as the get out of the gauss curve... (or whatever is best suited with your material) and you note the power value, you end up with the same passing value ( you can do the curve interpolation so as to be able to do the integration (the sum)).

6

New Theories / Re: Why light change its' speed and direction during refraction?

« on: 29/08/2022 09:57:22 »

I really am a scientist. I have a beard and glasses. I even have a white coat somewhere.

Me too and my beard is surely longer then yours.
Not sure this will help to understand refraction but at least you are funny.

7

New Theories / Re: New perspectives in physics

« on: 26/08/2022 14:13:30 »

Not at all, it shows the principle of visual perspective, an effect of the angles subtended at the eye

I dont agree with this.
The "perspective" has nothing to do with "the eye" or anything related to the view ("visual perspective"). It works with gravitation too, so nothing to do with some "eye").

But at least you are right when we consider some point : It is (only) a principle, based on some particular mathematical approach of tridimentional space.

It is prety amusing to understand that "we" accept that the contraction of space within RS is the reality and that we deny this possibility (it is the reality) for more simple facts.
So almost any physicist agree that perspective is an illusion but space contraction within RS is reality : Why those double standards ?

To make clear that this question is not closed, take a look at the many research about the reason why the space is 3 dimentional (so trying to understand this "principle").
And we actually know that 3D space + 1D time is not suited to describe the reality at any scale (10 or 11 dimensions could be better... when we start with the naive "perspective view" you talked about).

8

New Theories / Re: Why light change its' speed and direction during refraction?

« on: 10/08/2022 01:21:29 »

The link just restates the question and cites experimental results. It doesn't show the underlying mechanisms based on first principles.

I agree that the common explaination i actualy get looks more like a "what" answer than a "how" answer.
It is surprising that because "the what" answer seem complicated for most peoples, they accept and confuse it with the "how" answer every smart people would require.

9

Question of the Week / Re: QotW - 21.11.28 - Why do ant bites hurt so much?

« on: 26/07/2022 18:14:05 »

Most common ants dont inject anything because they dont have a sting.
They try to bite but their mandibles are harmless.
The mandibles dont inject anything like one spider could do.
But they have the possibility to spread the formic acid using their abdomen.
This acid, like the one of the nettles, when dropped on the skin, enter the pores of the skin.
This is what hurt, like the nettles.

Some more rare ants have stings, like the wasps (this is because they belong to the Hymenoptera order).
These ants inject poison and some are known to give one of the most great pain.
Trying to bear the pain is part of the initiation of some indigenous peoples living in the amazonian forest.

10

Plant Sciences, Zoology & Evolution / Re: Why doesn't evolution revert when environments change back?

« on: 19/07/2022 00:53:31 »

Specialisation and even hyperspecialisation do not mean evolutionary cul-de-sac.
Here an article about this :

Passion flowers with long nectar tubes depend entirely on the sword-billed hummingbird for pollination. However, as a new study by LMU researchers shows, the evolution of even such extreme specialization is by no means irreversible.
...
"This highly specialized mode of pollination is the result of a process of coevolution," says LMU's Professor Susanne Renner. "Such highly specialized adaptations need time to evolve, and this has led to the notion that their evolutionary trajectory is set in the direction of further refinement and can never be reversed." But, it turns out, evolution is no one-way street. By applying molecular phylogenetics and a so-called molecular clock, Renner and her colleagues Stefan Abrahamczyk (now at the University of Bonn) and Daniel Souto-Vilarós were able to show that the dependency of Tacsonia species on Ensifera ensifera for pollination has been lost several times over the course of a relatively brief period, geologically speaking.

Evolution can go into reverse

https://phys.org/news/2014-10-evolutionary-cul-de-sac.html

11

Plant Sciences, Zoology & Evolution / Re: Is ant behaviour instinctive?

« on: 14/07/2022 14:44:19 »

Yes, ants like other species belonging to the order of hymenoptera (and like other arthopodes) have a good ability to learn.
It is obvious that a new colony (the quen of the ants do not really teach anything to her offspring) only depends on the innate knowledge every individual possesses.
But they can learn and even can do inovation.

How do we know that ?

Concerning the hymenoptera order (ants are part of this order) :

Insects are also capable of behavioral innovations. Innovation is defined as the creation of a new or modified learned behavior not previously found in the population.[22] Innovative abilities can be experimentally studied in insects through the use of problem solving tasks.[23] When presented with a string-pulling task, many bumblebees cannot solve the task, but a few can innovate the solution. Those that initially could not solve the task can learn to solve it by observing an innovator bee solving the task. These learned behaviors can then spread culturally through bee populations.[21] More recent studies in insects have begun to look at what traits (e.g. exploratory tendency) predict the propensity for an individual insect to be an innovator.[24]

https://en.wikipedia.org/wiki/Insect_cognition

And because of the studies of the "mushroom bodies" (cerebral matter of insects).

One important and highly studied brain region involved in insect foraging are the mushroom bodies, a structure implicated in insect learning and memory abilities. The mushroom body consists of two large stalks called peduncles which have cup-shaped projections on their ends called calyces. The role of the mushroom bodies is in sensory integration and associative learning.[30] They allow the insect to pair sensory information and reward. Experiments where the function of the mushroom bodies are impaired through ablation find that organisms are behaviourally normal but have impaired learning. Flies with impaired mushroom bodies cannot form an odour association[31] and cockroaches with impaired mushroom bodies cannot make use of spatial information to form memories about locations.[32] Electrophysiological underpinnings of the cognition in different parts of the insect brain can be studied by various techniques including in vivo recordings from these parts of the insect brain.

https://en.wikipedia.org/wiki/Insect_cognition

12

Plant Sciences, Zoology & Evolution / Re: Why do birds tap on my windows?

« on: 14/07/2022 13:08:08 »

In all seriousness though, since birds are born into a world that has glass, then it would seem that glass is part of a birds natural environment.

Seriously ?
Birds dont know glass.
But after millions of years of evolution they know water in liquid and solid form.
It is amazing to know that they dont even need to learn what water is.
So if a bird tap on a windows, he try to peck ice or drink water.
 
Conclusion : A bird taping on a window is a thirsty bird.
To verify this hypothesis, just put a water bowl near the window and see if they prefer the strange "ice" or the known water.

13

Physics, Astronomy & Cosmology / Re: Why is inflation needed in the bbt?

« on: 25/06/2022 19:34:09 »

An other point of view.

PS1 :: National Conference on CICAHEP, Dibrugarh (2015), 01, 94 – 99
Horizon, homogeneity and flatness problems – do their resolutions really
depend upon inflation?
Ashok K. Singal
Astronomy and Astrophysics Division, Physical Research Laboratory, Navrangpura, Ahmedabad-380 009, Gujarat, India
asingal@prl.res.in; COS3, Poster, CICAHEP15.169.1
In textbooks and review articles on modern cosmology [1, 2, 3, 4, 5, 6] one almost invariably comes across a
section devoted to the subject of observed homogeneity and near-flatness of the universe, where it is argued that
to explain these observations inflation is almost a must. In fact that was the prime motive of Guth [7] to propose
inflation in the first place. We show that the arguments offered therein are not proper. The horizon problem, which
leads to the causality arguments, arises only in the world models where homogeneity and isotropy (cosmological
principle) is presumed to begin with. We do not know whether the horizon problem would still arise in non-
homogeneous world models. Therefore as long as we are investigating consequences of the cosmological models
based on Robertson-Walker line element, there is no homogeneity issue.
We also show that the flatness problem, as it is posed, is not even falsifiable.


The usual argument used in literature
is that the present density of the universe is very close (within an order of magnitude) to the critical density value.
From this one infers that the universe must be flat since otherwise in past at 10−35 second (near the epoch of
inflation) there will be extremely low departures of density from the critical density value (i.e., differing from
unity by a fraction of order ∼ 10−53), requiring a sort of fine tuning. Actually we show that even if the present
value of the density parameter (in terms of the critical density value) were very different, still at 10−35 second it
would in any case differ from unity by a fraction of order ∼ 10−53. For instance, even if had an almost empty
universe, with say, ρo ∼ 10−56 gm/cc or so (with density parameter Ωo ∼ 10−28, having a mass equivalent to
that of Earth alone to fill the whole universe), we still get the same numbers for the density parameter at the epoch
of inflation. So such a fine-tuning does not discriminate between various world models and a use of fine tuning
argument amounts to a priori rejection of all models with k 6 = 0, because inflation or no inflation, the density
parameter in all Friedmann-Robertson-Walker (FRW) world models gets arbitrarily close to unity as we approach
the epoch of the big bang. That way, without even bothering to measure the actual density, we could use any
sufficiently early epoch and use “extreme fine-tuning” arguments to rule out all non-flat models. Thus without
casting any whatsoever aspersions on the inflationary theories, we point out that one cannot use these type of
arguments, viz. homogeneity and flatness, in support of inflation.

https://s3.cern.ch/inspire-prod-files-c/cf01320a84f09089fdb2318c01fc440b

14

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 17/06/2022 23:57:50 »

It seems that the 1/r^2 law for gravity makes perfect sense, as it directly follows from the geometry of a point source.
Why would this contradict the conservation of energy?

It is complicated to explain shortly, but i will try my best.

So yes, you are right. If the gravity field would behaviour like the electromagnetic field you should have a 1/d^2 law for the gravitational field.
But first you need to really understand why there can be a 1/d^2 law in the intensity at some distant point for the electromagnetic field.
Lets begin with a source of photons that emit only 1 single photon.
This photon start form the point source and then advance toward infinity.
There is a problem if you want to receive this single photon, especialy if you are at a very long distance because if you consider the photon will spread as a cylinder (like a laser beam would do), the 1/d^2 law intensity would not apply everytime.
By chance, the photon spread as a cone, and you can intercept it much easyer.
So a single photon at a distance d can be received within a large surface onto the sphere wich has the radius d.
Whats the intensity law for this single photon ?
1/d^2 ? No, if you get the photon that is actualy present (because the duality particle wave) you got the full energy of this photon.And very important, if you get the photon within this surface, the photon disappear instantly (so far as we know) preventing anyone to receive the photon at the same time at an other position (the wave function is destroyed).
Now, if you consider a source that emit a tremedous quantity of photons, every second, like a star would do, the intensity of the source can be seen as if it would be distributed onto the surface of a sphere of radius d.
You can divide the intensity by d*d because you are in fact dividing the number of the photons you can intercept on the surface of the sphere.You are not dividing the intensity of the photon (you can not it is a particle), but their number.
It seems obvious at first, but there is something very interresting you need to understand there : As soon as you have interacted with the photon, it stop his travel and disappear and before you interact with it, it is like it is not here (it does nothing).
So : The intensity 1/d^2 can be obtained because of the large number of photons (they are well repartited) BUT you can ONLY obtain this intensity 1 time.
The maximum you can do is receiving all photons emited and you will have the same intensity as that of the star.
Saying you have a pulse of light (it is better to understand) 1/d^2 is proportional with the surface d^d  of the sphere of radius d. Here we dont have a problem with the energy.

Now, if you consider the gravitational field.
Let assume we have, like for the electromagnetic field, "something" that is spreading from the source (the same star as before per example). We dont need really, for the explaination here, to know what this "something" is (some graviton or whatever). But what we know, and it is was distinguish the behaviour of the gravitational field and the electromagnetic field; is that the photon is VIRTUAL (it exists virtualy in the space and has no effect unlike you receive it, and if it interact it disapear) and that the "something" who is responsible for the curvature of space-time is ACTUAL (it has a PERMANENT and real effect, everywhere where it travel).
Therefore, if you consider that it can curve the space-time (and this can be assimilated as some local energy change) everywhere he pass by, you will understand that you could theoritically do the sum of the energy change of the spheres with radius between 0 and the infinity.
Because the "graviton" or whatever it is, change actually the curvature of space-time, this would lead to an infinite energy gain because the radius will become bigger an bigger.
An if you want to interact with it like the photon, it must occupy a large amount of space, bigger and bigger as you go away from the source.
The photon can because it only occupy space without interact with it, but the "graviton" can not (or it is some big mystery) because it is actualy changing the curvature within the space-bigger and bigger it occupy. .

Therefore, my opinion is : The best, and i will finish briefly here, is to consider the "graviton" (or whatever it is) like some fluid that is occupying the area around the star.
The intensity of the fluid production is extremly strong, so the filling around the star is "like if" the "fluid balloon" extend around speed of light, but soon you go further, and because of the constant (proportional to mass) production of this fluid the "balloon" growing rate decrease.
The intensity around the star is proportional to 1/d^2 but soon you go further away the density of this fluid become less than 1/d^2... until some time when the area is well filled and so forth.
More interresting, with this model, you dont only say : What is the intensity of the gravitational field at distance d, but you also need to say WHEN do i consider this intensity..
Older structures, like for the galaxys, have more of this "fluid" then young galaxys.
And when the star is loosing mass... the gravitational effect remain somewhere.