I like to share my various interests for science, art, literature and many other fields. As there are already a lot of excellent blogs devoted to astrophysics, physics, general relativity, cosmology, etc., my own blog will be more specifically devoted to « scientific culture », trying to cover some of my fields of interest and activity at the intersection of science, history, literature, art, philosophy.
This anglophone blog, «e-luminesciences», is NOT a translation of my francophone blog «luminesciences» (https://blogs.futura-sciences.com/luminet/, that I recommend to all the lovers of French culture), since it will present original posts as well as some ones adapted from their French version.
Have a nice time !
How to simplify our vision of the twin paradox.
Time dilation is since Einstein reported in a rather complicated manner.
We look at the transported clock “A” with the “point de vue” from our fixed clock “B”. And of course we find that “A” runs slow.
But we forget that “all the laws of physics are the same in every inertial frame of reference”. That means ː if we transport , at constant speed a sister clock “A” of “B” , that sister clock runs exactly at the same rate than “B”.
And if we measure , with “A” , a certain amount of time between the initial position of “A” and its final position , we will find the correct answers (that is with the Lorentz transformations) , with never having thought that “A” runs slow. That means we dissipated any confusion between the physical clocks and time they measure ǃ
Of course we must also explain what happens in the acceleration – deceleration phases , but it is now well-known that the contribution of these phases are negligible. And also that modern clocks are almost insensible to accelerations ǃ
That interpretation is not only easier to explain , but it simplifies the experimental analysis. We understand how there is in space-time a sort of trading between space and time.
What do you think of my statement ?
Cordially
What matters is not the duration of acceleration phases (which can be very short) but the difference between the spacetime lengths of the twins’ trajectories. A striking illustration of this is the twin’s paradox revisited for multiply connected spacetimes, see e.g. my article https://arxiv.org/abs/physics/0006039
Dear Jean-Pierre Luminet, 30.04.2025
Describing the universe as an inflatable dodecahedron makes me guess that you’re a big soccer fan. Even more so since you assume that the Universe can also deflate and become wrapped. But who is going to blow up the universe and then let it deflate again?
If it’s true that the shape of the universe is a finite dodecahedron, then the universe is made up of cubes, because a dodecahedron is made up of 5 cubes.
At school, we learned that 0D is a point, 1D is a line (a collection of points), 2D is a surface (a collection of lines), and 3D is a shape (a collection of planes). Since René Descartes, we have been using a collection of three spatial axes—x, y, and z—as a coordinate system. But for the origin of the universe, it makes more sense to start with a collection of 3—x, y, z—spatial planes as a 3D coordinate system.
With three squares, you can create both a hexahedron and an octahedron, and with three rectangles, you can create an icosahedron, but for a dodecahedron, you need five rectangles or five cubes.
Wouldn’t it be simpler and more consistent to apply the dimension rules as follows: 0D = point or dot, 1D = line or collection of dots, 2D = plane or collection of lines, 3D = shape or collection of planes (hexahedron, octahedron, dodecahedron and icosahedron), 4D = polyhedron or collection of shapes (dodecahedron), and 5D = collection of polyhedra? On a screen, a dot is already 2D, but in the universe, it must be 3D and where is the tetrahedron?
In my opinion, the shape of the universe is a finite exintahedron, a regular sixty-sided polyhedron with 32 vortices, 16 spatial axes (hexadecimal) within which a cubic grid is created consisting of 0qbits (empty) through which the inhaling and exhaling rotation creates Xqbits (waves inhale), Yqbits (superposition) and Zqbits (particles exhale). This exintahedron creates a natural division into seven levels and an all-encompassing 33rd vortex as central awareness (Christ consciousness, Shiva being, Buddha’s nature or Horus power).
If you are interested, I can send you further information.
Best regards, Peter Gabriël Visser