8 mai 2015
5
08
/05
/mai
/2015
13:08
I have studied physics during several years at the university. In this article, I shall explain why theoretical physicists are mostly bad scientists.
I A bad mathematical level
II A lack of experience
III Conclusion
I A bad mathematical level
In a French elite school called "maths sup", I learnt a lot of things from a good mathematics teacher. I must admit that if I haven't done that year, I couldn't now criticize the lack of mathematical knowledge from physicists.
A common mistake is to say "the f(x) function". f(x) is no function ; the function is f.
Another common mistake is to consider that the => arrow means "so". The mathematical meaning of that sign is "implies".
I am not sure, but a physicist known as Frédéric FAURE is said to be strong in mathematics, but does the same common mistakes as the others.
Actually, most physicists don't know the bases of mathematics, concepts like a ntuple, morphism, function, are not known by them.
II A lack of experience
A problem of theoretical physics is that the theories (supersymmetry, string theories...) are not based upon experience. It makes them little scientific, and for sure, out of the touch of reality.
A theory based on experience is scientifically solid.
On the other side, a theory based upon another theory is less sure.
III Conclusion
Dark matter we don't see, dark energy we don't see, upper dimensions we don't see... Theoretical physics is lost. The phenomenom dates from the end of the 19th century, where physicists were looking for a thing called aether. Einstein said that aether does not exist. But if I say that dark matter and dark energy do not exist, will the physicists listen to me ?
Actually, as Lee SMOLIN underlined, the problem is that the little revolutionaries, the people that theoretical physics need, are rejected out of the social middle. It is really hard to make the 8+ years of study to the PhD...
All these facts led me to consider that theoretical physics is a pseudoscientific sect.
Published by Bête spatiotemporelle

dans
Sciences (Eng)
25 février 2015
3
25
/02
/février
/2015
18:39
I wrote long ago... very long ago, that I would publish an article about relativity theory. I will do my best. I don't have much education about relativity theory, but I can say some things about it. Listen carefuly and don't be afraid. If there is something you don't understand, ask a question.
I Principle of relativity
II Lorentz transformation
III Einstein's interpretation
IV Paradox of twins
I Principle of relativity
The principle of relativity is one law among others that characterize the universal laws of Nature. It says :
"The laws of Nature are the same whatever the mechanical referential."
In the Sun's mechanical referential, the Earth rotates around the Sun. But in the Earth mechanical referential, we see the Sun rise in the morning and set in the evening.
There are other kinds of laws. I would say that the laws of Nature are the same whatever the size of the considered object.
Actually, the principle of relativity is rather a principle of absolute.
When he was working about making electromagnetic laws abiding by the principle of "relativity", a man called Hendrik LORENTZ found some mathematical relations.
II Lorentz transformation
When you look at something, say, an elephant eating a fruit, it takes some space and some time. This is what we call "an event", in special relativity.
Lorentz found the solution of his problem only for a part of cases. He found the solution for a mechanical referential going straight at the same speed in another referential. This looked like this.
Lengths and times are multiplied or divided by gamma.
If you don't understand at this point, it's OK. I just wanted to show you the classical formula, so you can think "I've seen that somewhere else.".
What do these formulaes mean ? Here comes Einstein.
III Einstein's interpretation
Three people were working on this electromagnetism problem : Lorentz, Poincaré and Einstein.
Einstein had the strongest interpretation. He said that the gamma factor changing the lengths and the times was a sign that space and time are not absolute.
The absolute came to be the speed of light, making special relativity a modern theory of light.
The strange effects of special relativity cannot be seen in the normal life. They can be seen only for things getting so fast that they nearly have the speed of light, c. Lengths seem smaller and times seem bigger. The elephant would seem smaller in size and slower to eat its fruit.
A physicist called Thierry CHAMBON said that times seem bigger and lengths smaller because of a perspective effect within the spacetime.
IV Paradox of twins
Let us put ourselves in the Earth's referential. Let us imagine two twins A and B. The A twin takes a spaceship travelling nearly as fast as the speed of light ; the B twin stays on the Earth. Then A comes back to Earth. Due to the time dilatation, it would be possible for A to age 2 years whereas B ages 40 years. But
 if we consider the problem from the spaceship referential, it is the contrary : A ages 40 years and B ages 2 years ;
 we supposed that the spaceship goes straight with a constant speed. When accelerating, the problem must be considered with another theory : general relativity.
The physicist Vincent MORENAS said it is maybe actually the same time for both of twins (40 years for A and 40 years for B).
Published by Bête spatiotemporelle

dans
Sciences (Eng)
21 décembre 2014
7
21
/12
/décembre
/2014
13:35
I wanna travel around the world, to discover new things. I decided to take a lot of books, and I told myself that a book of knowledge when you look at the sky could be nice.
This is why I bought an ephemeris book. The ephemeris is all the basic astronomical data fron which you can infer a lot of things.
This is how it looks inside.
The solar eclipse of March 2015 will be total in the Faroe islands, but unfortunately, there may be a cloudy sky. I wish I see a total solar eclipse at least once in my life...
Published by Bête spatiotemporelle

dans
Sciences (Eng)